[Guide] Difference between UFS2.0 and UFS2.1 Flash, not the speed! - Huawei Mate 9 Questions & Answers

Hi there, UFS2.0 and UFS2.1 are the standards by JEDEC.
UFS2.0 is generated in Sept. 2013, and UFS2.1 in Mar. 2016, as a complementary of UFS2.0.
a) Related documents:
UFS2.0:JESD220B (Sept. 2013)
UFS2.1:JESD220C (Mar. 2016)
b) About speed:
No matter the flash is UFS2.0 or UFS2.1, they must support HS-G2 interface physical layer agreement (1-Lane up to 2.9Gbps and 2-lane up to 5.8Gbps). And HS-G3 is optional (1-Lane up to 5.8Gbps and 2-lane up to 11.6Gbps).
Speed is not the discrimination of UFS2.0 and UFS2.1!
UFS2.1 flash memories are regularly faster only because they are newest products and with better integrated controllers and flash cell technologies.
c) About the differentiation between UFS2.0 and UFS2.1:
JESD220C Universal Flash Storage version 2.1 offers key improvements over earlier versions and will provide data security through the use of inline cryptography between the SoC and UFS Storage device.
UFS 2.1 defines the following updates over the prior version of the standard:
i) Inclusion of a Device Health Descriptor: the descriptor provides detailed information on the life of a device, thus allowing for better preventative maintenance, which is advantageous to most areas of the market and especially important in the automotive market.
ii) Addition of Secure Write Protection: this allows for the use of fine-grained write protection as required by modern high-level operating systems (OS) and applications.
iii) Field Firmware Update: enables the device vendor to improve performance and implement bug fixes, as well as facilitating the addition of new features in products that have already shipped to end customers.
iv) Command priority: improves system performance, allowing the software to assign higher priority to more urgent tasks.
So the auxiliary functions are the differences between UFS2.0 and UFS2.1.
d) Want to know what exactly your flash is (Part Number & UFS2.0/2.1)? Please click here (do not need to ROOT):
https://forum.xda-developers.com/mate-9/help/guide-method-to-flash-part-to-ufs2-0-t3598938
__________________
Updates:
This post is talking about UFS2.1 and UFS2.0 Standard, not the specific flash memory products.
So some statements are true here:
a) UFS2.1 standard is not faster than UFS2.0 standard.
b) For the mobile flash memory products from the same company, the UFS2.1 flash memory product is usually better/faster than the UFS2.0 flash memory product, because the former is new.

xlgssss said:
Hi there, UFS2.0 and UFS2.1 are the standards by JEDEC.
UFS2.0 is generated in Sept. 2013, and UFS2.1 in Mar. 2016, as a complementary of UFS2.0.
a) Related documents:
UFS2.0:JESD220B (Sept. 2013)
UFS2.1:JESD220C (Mar. 2016)
b) About speed:
No matter the flash is UFS2.0 or UFS2.1, they must support HS-G2 interface physical layer agreement (1-Lane up to 2.9Gbps and 2-lane up to 5.8Gbps). And HS-G3 is optional (1-Lane up to 5.8Gbps and 2-lane up to 11.6Gbps).
Speed is not the discrimination of UFS2.0 and UFS2.1!
UFS2.1 flash memories are regularly faster only because they are newest product and with better integrated controllers and flash cell technologies.
c) About the differentiation between UFS2.0 and UFS2.1:
JESD220C Universal Flash Storage version 2.1 offers key improvements over earlier versions and will provide data security through the use of inline cryptography between the SoC and UFS Storage device.
UFS 2.1 defines the following updates over the prior version of the standard:
i) Inclusion of a Device Health Descriptor: the descriptor provides detailed information on the life of a device, thus allowing for better preventative maintenance, which is advantageous to most areas of the market and especially important in the automotive market.
ii) Addition of Secure Write Protection: this allows for the use of fine-grained write protection as required by modern high-level operating systems (OS) and applications.
iii) Field Firmware Update: enables the device vendor to improve performance and implement bug fixes, as well as facilitating the addition of new features in products that have already shipped to end customers.
iv) Command priority: improves system performance, allowing the software to assign higher priority to more urgent tasks.
So the auxiliary functions are the differences between UFS2.0 and UFS2.1.
d) Want to know what exactly your flash is (Part Number and UFS2.0/2.1)? Please click here:
https://forum.xda-developers.com/mate-9/help/guide-method-to-flash-part-to-ufs2-0-t3598938
Click to expand...
Click to collapse
Please look at C - iv and tell me what is the improvement in performance.
Reduction of heat?

zayidhs said:
Please look at C - iv and tell me what is the improvement in performance.
Reduction of heat?
Click to expand...
Click to collapse
C iv is a function to increase the system performance (operating speed of urgent tasks) of the phone. Seems not related to power loss and heat.

So, this improvement which has been introduced in 2.1 but is lacking in 2.0 will make the 2.1 faster by improving operating speeds right?
How then is speed not a factor in difference between the two?

zayidhs said:
So, this improvement which has been introduced in 2.1 but is lacking in 2.0 will make the 2.1 faster by improving operating speeds right?
How then is speed not a factor in difference between the two?
Click to expand...
Click to collapse
Replied you in the other post: https://forum.xda-developers.com/mate-9/help/guide-method-to-flash-part-to-ufs2-0-t3598938

zayidhs said:
So, this improvement which has been introduced in 2.1 but is lacking in 2.0 will make the 2.1 faster by improving operating speeds right?
How then is speed not a factor in difference between the two?
Click to expand...
Click to collapse
The flash memory companies always say something like 'our ufs2.1 product is 40% faster than the prevous version' BLABLABLA. But this speed improvement is not because of UFS2.x Standard. This is becuase that they are new product. And the company must improve them to attract the customers. And "UFS2.1" in their advertisement is just another same-level feature (as of the speed) of the product, to make it attractive.

Related

[GUIDE]Complete guide for Galaxy 3 I5800/I5801

The Complete Guide For Galaxy 3 i5800/i5801
​
Index:
1) Android Basics
2) Galaxy 3 Features
3) Hardware
4) ROM Basics, Tutorials
5) Kernel Basics
6) Tools/Imp Download Links
7) Complete List of ROMs,Kernels for G3
8) FAQ
9) EPIC Fail Ideas for G3
Android Basics
1) Android Basics​
Introduction:
Android is a software stack for mobile devices that includes an operating system, middleware and key applications. Google Inc. purchased the initial developer of the software, Android Inc., in 2005. Android's mobile operating system is based on the Linux kernel. Google and other members of the Open Handset Alliance collaborated on Android's development and release. The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android. The Android operating system is currently the world's best-selling Smartphone platform.
Android has a large community of developers writing applications ("apps") that extend the functionality of the devices. There are currently over 200,000 apps available for Android. Android Market is the online app store run by Google, though apps can also be downloaded from third-party sites. Developers write primarily in the Java language, controlling the device via Google-developed Java libraries.
The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the Open Handset Alliance, a consortium of 80 hardware, software, and telecom companies devoted to advancing open standards for mobile devices. Google released most of the Android code under the Apache License, a free software and open source license.
The Android open-source software stack consists of Java applications running on a Java-based, object-oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc. The Android operating system, including the Linux kernel, consists of roughly 12 million lines of code including 3 million lines of XML, 2.8 million lines of C, 2.1 million lines of Java, and 1.75 million lines of C++.
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Version history
2.1 Eclair
Changelog:
Sync: Expanded Account sync. Multiple accounts can be added to a device for email and contact synchronization
Email: Exchange support, Combined inbox to browse email from multiple accounts in one page.
Bluetooth: 2.1 support
Contacts: Tap a contact photo and select to call, SMS, or email the person.
Messaging: Search all saved SMS and MMS messages. Auto delete oldest messages in a conversation when a defined limit is reached.
Camera: Flash support, Digital zoom, Scene mode, White balance, Color effect, Macro focus
Virtual keyboard: Improved typing speed, smarter dictionary learns from word usage and includes contact names as suggestions.
Browser: Refreshed UI, Bookmark thumbnails, Double-tap zoom, Support for HTML5
Calendar: Agenda view enhanced, Attending status for each invitee, Invite new guests to events.
System: Optimized hardware speed, Revamped UI
Display: Support for more screen sizes and resolutions, Better contrast ratio
Maps: Improved Google Maps 3.1.2
MotionEvent class enhanced to track multi-touch events
Live Wallpapers: Home screen background images can be animated to show movement
2.2 Froyo
Changelog:
System: Speed, memory, and performance optimizations
Additional application speed improvements courtesy of JIT implementation
Integration of Chrome's V8 JavaScript engine into the Browser application
Improved Microsoft Exchange support (security policies, auto-discovery, GAL look-up, calendar synchronization, remote wipe)
Improved application launcher with shortcuts to Phone and Browser applications
USB tethering and Wi-Fi hotspot functionality
Added an option to disable data access over mobile network
Updated Market application with batch and automatic update features
Quick switching between multiple keyboard languages and their dictionaries
Voice dialing and contact sharing over Bluetooth
Support for numeric and alphanumeric passwords
Support for file upload fields in the Browser application
Support for installing applications to the expandable memory
Adobe Flash support
Support for extra high DPI screens (320 dpi), such as 4" 720p
2.3 Gingerbread
Changelog:
System: Updated user interface design for simplicity and speed
Display: Support for extra-large screen sizes and resolutions (WXGA and higher)
Internet calling: Native support for SIP VoIP telephony
Virtual Keyboard: Faster, more intuitive text input, improved accuracy, better suggested text. Voice input mode
Copy/Paste: Enhanced. Select a word by press-hold, copy, and paste.
Near Field Communication lets the user read an NFC tag embedded in a poster, sticker, or advertisement.
New audio effects such as reverb, equalization, headphone virtualization, and bass boost
System: Improved power management with a more active role in managing apps that are keeping the device awake for too long.
Download Manager gives the user easy access to any file downloaded from the browser, email, or another application.
Camera: Access multiple cameras on the device, including a front-facing camera, if available.
Media: Support for WebM/VP8 video playback, and AAC audio encoding
System: Enhanced support for native code development
Audio, graphical, and input enhancements for game developers
Concurrent garbage collection for increased performance
Native support for more sensors (such as gyroscopes and barometers)
Switched from YAFFS to ext4 on newer devices
Android Architecture
FEATURES OF ANDROID
Handset layouts The platform is adaptable to larger, VGA, 2D graphics library, 3D graphics library based on OpenGL ES 2.0 specifications, and traditional smartphone layouts.
Storage SQLite, a lightweight relational database, is used for data storage purposes
Connectivity Android supports connectivity technologies including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi (no connections through Proxy server and no Ad hoc wireless network), LTE, NFC and WiMAX.
Messaging SMS and MMS are available forms of messaging, including threaded text messaging and now Android Cloud To Device Messaging Framework(C2DM) is also a part of Android Push Messaging service.
Multiple Language Support Multiple languages are available on Android. The number of languages more than doubled for the platform 2.3 Gingerbread. Android lacks font rendering of several languages even after official announcements[citation needed] of added support (e.g. Hindi).
Web browser The web browser available in Android is based on the open-source WebKit layout engine, coupled with Chrome's V8 JavaScript engine. The browser scores a 93/100 on the Acid3 Test.
Java support While most Android applications are written in Java, there is no Java Virtual Machine in the platform and Java byte code is not executed. Java classes are compiled into Dalvik executables and run on the Dalvik virtual machine. Dalvik is a specialized virtual machine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. J2ME support can be provided via third-party applications.
Media support Android supports the following audio/video/still media formats: WebM, H.263, H.264 (in 3GP or MP4 container), MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or 3GP container), MP3, MIDI, Ogg Vorbis, FLAC, WAV, JPEG, PNG, GIF (though earlier versions do not support animated GIFs, BMP.
Streaming media support RTP/RTSP streaming (3GPP PSS, ISMA), HTML progressive download (HTML5 <video> tag). Adobe Flash Streaming (RTMP) and HTTP Dynamic Streaming are supported by the Flash plugin. Apple HTTP Live Streaming is supported by RealPlayer for Mobile, and by the operating system in Android 3.0 (Honeycomb). Microsoft Smooth Streaming is planned to be supported through the awaited port of Silverlight plugin to Android.
Additional hardware support Android can use video/still cameras, touchscreens, GPS, accelerometers, gyroscopes, magnetometers, dedicated gaming controls, proximity and pressure sensors, thermometers, accelerated 2D bit blits (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics.
Multi-touch Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero. The feature was originally disabled at the kernel level (possibly to avoid infringing Apple's patents on touch-screen technology at the time). Google has since released an update for the Nexus One and the Motorola Droid which enables multi-touch natively.
Bluetooth Supports A2DP, AVRCP, sending files (OPP), accessing the phone book (PBAP), voice dialing and sending contacts between phones. Keyboard, mouse and joystick (HID) support is available through manufacturer customizations and third-party applications. Full HID support is planned for Android 3.0 (Honeycomb).
Video calling Android does not provide native video calling support, but some handsets have a customized version of the operating system that support it, either via the UMTS network (like the Samsung Galaxy S) or over IP. Video calling through Google Talk is available in Android 2.3.4 and later.
Multitasking Multitasking of applications is available.
Voice based features Google search through voice has been available since initial release. Voice actions for calling, texting, navigation, etc. are supported on Android 2.2 onwards.
Tethering Android supports tethering, which allows a phone to be used as a wireless/wired hotspot. Prior to Android 2.2 this was supported by third-party applications or manufacturer customizations.
Screen Capture Android does not currently support screenshot capture. This is supported by manufacturer and third-party customizations.
2) Galaxy 3 Features​
General
2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 900 / 2100
Announced 2010, June
Status Available. Released 2010, July
SIZE
I5801
Dimensions 113.5 x 55 x 12.6 mm
Weight 113 g
I5800
Dimensions 113.5 x 55 x 12.9 mm
Weight 109 g
DISPLAY
Type TFT capacitive touchscreen, 16M colors
Size 240 x 400 pixels, 3.2 inches
Features - Touch Wiz 3.0
- Accelerometer sensor for UI auto-rotate
- Proximity sensor for auto turn-off
- Multi-touch input method
SOUND
Alert types Vibration; MP3, WAV ringtones
Loudspeaker Yes
3.5mm jack Yes
- DNSe (Digital Natural Sound Engine)
MEMORY
Phonebook Practically unlimited entries and fields, Photocall
Call records Practically unlimited
Internal 512MB ROM, 256MB RAM
Card slot microSD, up to 32GB
DATA
GPRS Class 10 (4+1/3+2 slots), 32 - 48 kbps
EDGE Class 10, 236.8 kbps
3G HSDPA, 3.6 Mbps
WLAN Wi-Fi 802.11 b/g/n, Wi-Fi hotspot (Android 2.2)
Bluetooth Yes, v3.0 with A2DP
Infrared port No
USB Yes, v2.0 microUSB
CAMERA
Primary 3.15 MP, 2048x1536 pixels, autofocus
Features Geo-tagging, face and smile detection
Video Yes, [email protected]
Secondary No
SOFTWARE
OS Android OS, v2.1 (Eclair), upgradable to v2.2
CPU Samsung S5P6442 667 MHz processor
Messaging SMS(threaded view), MMS, Email, Push Mail, IM
Browser HTML
Radio Stereo FM radio with RDS
Games
Colors Black, White
GPS Yes, with A-GPS support
Java Yes, via Java MIDP emulator
- Orange Application Shop
- Orange Maps, Orange TV, Orange Push Email
- Contact Back & Restore, Orange Photo
- Digital compass
- MP4/DivX/XviD/WMV/H.264/H.263 player
- MP3/WAV/eAAC+ player
- Organizer
- Document editor(Word, Excel, PowerPoint, PDF)
- Google Search, Maps, Gmail, YouTube, Calendar, Google Talk integration
- Voice memo
- Predictive text input
BATTERY
Type Standard battery, Li-Ion 1500 mAh
Stand-by Up to 620 h (2G) / Up to 480 h (3G)
Talk time Up to 15 h 30 min (2G) / Up to 7 h 15 min (3G)
3) Hardware​
Processor: Samsung S5P6442 (It is modified version of S5P6440)
General Description
SAMSUNG's S5P6440, AKA "Vega-L", is the first member of the "Vega" Series, which is our newest family of Application Processors. Each Application Processor in the Vega Series will maintain a high level of compatibility with each other in order to allow for PND Makers to design their entire line-up of products on a single SoC platform.
The S5P6440 will be Samsung's first AP designed solely for PND's with a strong emphasis on high performance while maintaining cost competitiveness.
In terms of performance, the S5P6440 is run by a powerful ARM1176 processor running at 533MHz, 667MHz with a 64-bit AXI bus.
Additionally, the S5P6440 features both 2D Graphics HW and OpenVG HW, thus providing exceptional graphics acceleration for mainstream PND products. We have also focused heavily on providing optimum IP's and interfaces in order to reduce the Bill-of-Materials of the system as a whole. As an example, the S5P6440 features upgraded NAND Error Correction HW to be able to support next generation MLC NAND Flash devices. The S5P6440 also supports serial LCD protocols via the MIPI DSI standard, which allows for lower cost, lower EMI and simpler integration.
Block Diagram
Features
ARM1176JZF-S 533MHz, 667MHz, 16KB/16KB L1 Cache with Java acceleration Engine
Memory Subsystem
- NAND Flash Interface with x8 data bus, with 1/4/8/12/16-bit hardware ECC circuit and 4KB page mode
- Mobile DDR Interface with x16 or x32 data bus (up to 333Mbps/pin)
- DDR2 Interface with x16 or x32 data bus (up to 333Mbps/pin)
2D Graphics Accelerator with BitBlit and Rotation
Vector Graphics Accelerator with dedicated Anti-Aliasing HW
1/2/4/8 bpp Palletized or 8/16/24bpp Non-Palletized Color-TFT support up to 800x480
Serial LCD I/F support with MIPI DSI
- Two data lanes and one clock lane
4 channel UART: 1 channel muxed with IrDA SIR/FIR
1 channel I2S
2 channel I2C interface support
3 channel MMC/SDHC/SDIO (or 1 ch HS-MMC & 1 ch SD/MMC/SDIO)
On-chip USB 2.0 OTG controller and PHY transceiver supporting high speed
Real time clock, 3 PLL's, timer with PWM and watch dog timer
8 channel DMA controller
12 channel 12-bit ADC (Touch screen interface)
2 channel SPI: 1ch muxed with TSI (transport stream interface)
Configurable GPIOs
Technical Documents:
The Only Technical Document that we have currently is the User Manual of S3C6410 RISC Processor. It is not exactly same as S5P6442 but can be used as a reference.
Download S3C6410 User Manual
TouchScreen: ATMEL mXT224(AT42QT602240)
General Desciption
A 224-node highly configurable touchscreen controller that is part of the Atmel maXTouch product platform. An optimal and scalable architecture enables smart processing of a capacitive touch image to accurately regenerate and report the user’s interaction with the touchscreen. Multi-touch performance identifies and individually tracks touches and allows a range of built-in gestures to be reported to the host processor. The IC provides position data of 12-bit x 12-bit resolution, as well as information on the size and angle of touch. Position data is reported at >250Hz, providing fast and smooth finger tracking, making it suitable for use with demanding applications such as handwriting recognition. Due to the high signal-to-noise ratio (SNR) of up to 80:1, the device works well with fingertip touch and can also be used with a conductive stylus. It is designed to work in demanding, rapidly changing environments. Only the touchscreen area is touch-sensitive, allowing design freedom to place the chip on the main board or adjacent to the sensor. The device is ideally suited to mobile phone-sized touchscreens and can also be used on screens of up to 7", supporting single-touch or two-touch with a larger finger separation.
Technical Documents
mXT224 Datasheet
TFT LCD PANEL: Samsung S6D04D1
General Description
S6D04D1 is a single-chip display driver IC for a TFT-LCD panel. Integrated on this chip are source drivers with built-in
memory, gate drivers and power sources. S6D04D1 can support a TFT-LCD panel up to a resolution of 240-RGB x 432-
dot graphics with 16M-color. S6D04D1 also supports various types of peripheral interface such as 80-series MCU
interface (8-/9-/16-/18-/24-bits data), 3-wire 9bit / 4-wire 8bit serial interface, and MDDI(Mobile Display Digital Interface)
S6D04D1 supports various types of RGB interface (24-/18-/16-/8-/6-bits data).
The Integrated on-chip functions that are described in this document include:
- Power saving: It reduces the overall power consumed in a TFT-LCD panel module.
- Internal GRAM:
- Internal DC/DC voltage converter
- MIE (Mobile Image Enhancement) functions
S6D04D1 features several power saving functions to reduce the overall power consumed in a TFT-LCD panel module:
S6D04D1 operates at low voltage and has internal GRAMs that can store 240-RGB x 432-dot 16M-color image data. In
addition, it has an internal DC/DC voltage converter that generates various voltages needed for driving the TFT-LCD
panel by using breeder resistors and the voltage followers.
Features
A single-chip TFT-LCD Controller/gate driver/source driver with built-in Graphic RAM
Supported Display panel resolution: 240*R/G/B (H) * 432 (V) , 240*R/G/B (H) * 400 (V) & 240*R/G/B (H) * 320 (V)
Integrated 2,488,320bit of graphic RAM (GRAM)
-GRAM configuration: 240 x 432 x 24-bits = 2,488,320bits
Supported Interfaces
-3-wire 9-bit data, 4-wire 8-bit data serial interface (for RGB parallel Interface)
-8-/9-/16-/18-/24- bit interface with 80-Series MCU (so called 80-Series)
-VSYNC I/F
-MDDI(Mobile Display Digital Interface)
Outputs
-Common electrode output
-Gate outputs
-Source outputs
Color Display mode
-Full color mode (Idle mode off): 16M / 260k / 65k colors
-Reduced color mode (Idle mode on): 8-colors (3-bit binary mode)
Color modes on the display host interface
-16-bits/Pixel: RGB= (565) using the 1,843k bit frame memory
-18-bits/Pixel: RGB= (666) using the 1,843k bit frame memory
-24-bits/Pixel: RGB= (888) using the 1,843k bit frame memory
Display features
-Partial display mode
Driving scheme: line inversion & frame inversion
MIE (Mobile Image Enhancement) functions
-Adaptive luminance/contrast enhancement function.
-Reduce the power consumption of backlight.
SE ( Sharpness Enhancement) functions
On-chip functions
-Voltage Boosters
-Adjustable VCOM voltage source generator
-An oscillator for display clock generation & Timing generation
-Factory default value (Contrast, Module ID, Module version, etc) can be stored inside IC
-MTP (Multi-time Programmable) Memory
-MTP initialization & program voltages are generated automatically from the built-in power circuit.
-Each 8-bits product ID1, ID2, ID3
-6-bits VCM Offset adjustment
-Each 5-bits for VML, GVD Offset adjustment
-1 bit for MTP writing protection
Voltage Supplies
-2.3V – 3.3V for VCI, supply voltage for Analog blocks
-1.65V – 3.3V for VDD3, Supply voltage for I/O
Output voltage levels
-2.5V to 5.0V for GVDD, Source output voltage
-AVDD, Power supply for driver circuit (Note 1)
-Maximum 6.0V for VCOM, Common electrode output voltage
-11.25V to 16.50V for VGH, Positive Gate output voltage (Note 2, Note 3)
--13.75V to - 6.75V for VGL, Negative Gate output voltage (Note 2)
CMOS compatible inputs
COG package
Operating temperature range: -40℃ to +85℃
Technical Documents
S6D04D1 Datasheet
4) ROM Basics, Tutorials​
STOCK ROM
A stock ROM is the version of the phone's operating system that comes with your phone when you buy it.
Samsung letter code
AW-Hungary AZ-France BD-Cyprus, Greece BY-Greece CB-Poland CE-Benelux CP-Denmark, Finland, Norway, Sweden DB-Vietnam DC-Thailand DD-India DT-Australia DX-Indonesia, Malaysia, Philippines, Singapore, Vietnam DZ-Malaysia, Singapore JA-South Africa JC-Algeria, Morocco, Nigeria, South Africa, Tunisia JP-Arabic JR-Arabic JV-Algeria, Egypt, Iran, Iraq, Kuwait, Morocco, Nigeria, Oman, Pakistan, Saudi Arabia,South Africa, Syria, Tunisia, Turkey JW-West Africa JX-Algeria, Egypt, Iran, Iraq, Kuwait, Morocco, Nigeria, Oman, Pakistan, Saudi Arabia,South Africa, Syria, Tunisia, Turkey KA-Turkey ME-France MK-Serbia MS-France, Germany, Italy, Netherlands, Portugal, Spain, Turkey, UK MT-Switserland MY-Italy NH-Latvia PO-France PU-Russia UB-Brazil XA-Austria, France, Germany, Italy, Netherlands, Switzerland, United Kingdom XB-Denmark, Norway, Sweden XC-Portugal, Spain XD-Croatia, Czech, Hungary, Slovakia XE-Bulgaria, Estonia, Kazakhstan, Latvia, Lithuania, Russia, Ukraine XF-Bulgaria, Croatia, Romania XP-UK, France, Italy, Spain, Netherlands, Poland, Portuguese, Turkey XX-Austria, Belgium, France, Germany, Hungary, Italy, Spain, United Kingdom XW-Austria, Belgium, France, Germany, Hungary, Italy, Spain, United Kingdom ZC-China, Hong Kong ZH-Hong Kong ZS-China, Hong Kong ZT-Taiwan
Custom ROM
A custom ROM is a fully standalone version of the OS, including the kernel (which makes everything run), apps, services, etc - everything you need to operate the device, except it's customized by someone in some way.
So what does the "customized" part mean? Since Android is open source, developers are free to take stock ROMs, modify them, strip them of garbage, optimize them, add things, and pretty much do whatever their imagination and skills allow.
Flashing
Flashing Process is basically, installing a new ROM/Kernel, Stock/Custom, via Odin.
Odin is a software used to flash ROM's to the phone in the Download Mode.
Odin used for Galaxy 3 is v4.252.
Steps to follow:
1) Install Samsung Kies
2) Connect phone to PC and let it detect and install drivers automatically.
3) Download Odin with ops file from here.
4) Extract them to some folder.
5) Run Odin as Administrator.
6) Odin will now open.
7) Put phone in download mode. (Vol Down + HOME + POWER)
8) Connect Phone to PC via USB and wait till Odin shows detected.
9) Select One Package.
10) Select .ops file and .tar file for flashing.
11) Press Start button.
12) Wait till the message box on odin shows the following message and phone reboots.
13) You have now successfully flashed new ROM / Kernel.
Rooting
Rooting is a process that allows users of cellphones and other devices running the Android operating system to attain privileged control (known as "root access") within Android's Linux subsystem, similar to jailbreaking on Apple devices running the iOS operating system, overcoming limitations that the carriers and manufacturers put on such phones.
Most retail devices running the Android operating system must be rooted in order to install custom versions of the Android system such as CyanogenMod. This is because in the stock configuration (unrooted), user-installed applications do not have direct access to the flash memory chip on the device and, thus, are not able to replace or modify the operating system itself. Rooting is also necessary for certain applications and widgets that require additional system and hardware rights such as for rebooting the phone, certain backup utilities, and other access to other hardware such as status LEDs. Rooting is also needed to disable or remove manufacturer-installed applications such as City ID. Rooting the phone typically also includes installing an application called Superuser that supervises which applications are granted root rights.
Steps to follow:
1) Download SuperOneClick - Download
2) Run SuperOneClick
3) Press on Root
4) It will show "Waiting for device"
5) Put your phone in USB Debugging Mode.
6) Connect to PC via USB Cable.
7) Press Yes, for the subsequent messages that follow
8) Done
Deodexing
WHAT IS AN ODEX FILE?
In Android file system, applications come in packages with the extension .apk. These application packages, or APKs contain certain .odex files whose supposed function is to save space. These ‘odex’ files are actually collections of parts of an application that are optimized before booting. Doing so speeds up the boot process, as it preloads part of an application. On the other hand, it also makes hacking those applications difficult because a part of the coding has already been extracted to another location before execution.
THEN COMES DEODEX
Deodexing is basically repackaging of these APKs in a certain way, such that they are reassembled into classes.dex files. By doing that, all pieces of an application package are put together back in one place, thus eliminating the worry of a modified APK conflicting with some separate odexed parts.
In summary, Deodexed ROMs (or APKs) have all their application packages put back together in one place, allowing for easy modification such as theming. Since no pieces of code are coming from any external location, custom ROMs or APKs are always deodexed to ensure integrity.
HOW THIS WORKS
For the more geeky amongst us, Android OS uses a Java-based virtual machine for running applications, called the Dalvik Virtual Machine. A deodexed, or .dex file contains the cache used by this virtual machine (referred to as Dalvik-cache) for a program, and it is stored inside the APK. An .odex file, on the other hand, is an optimized version of this same .dex file that is stored next to the APK as opposed to inside it. Android applies this technique by default to all the system applications.
Now, when an Android-based system is booting, the davlik cache for the Davlik VM is built using these .odex files, allowing the OS to learn in advance what applications will be loaded, and thus speeds up the booting process.
By deodexing these APKs, a developer actually puts the .odex files back inside their respective APK packages. Since all code is now contained within the APK itself, it becomes possible to modify any application package without conflicting with the operating system’s execution environment.
ADVANTAGES & DISADVANTAGES
The advantage of deodexing is in modification possibilities. This is most widely used in custom ROMs and themes. A developer building a custom ROM would almost always choose to deodex the ROM package first, since that would not only allow him to modify various APKs, but also leave room for post-install theming.
On the other hand, since the .odex files were supposed to quickly build the dalvik cache, removing them would mean longer initial boot times. However, this is true only for the first ever boot after deodexing, since the cache would still get built over time as applications are used. Longer boot times may only be seen again if the dalvik cache is wiped for some reason.
For a casual user, the main implication is in theming possibilities. Themes for android come in APKs too, and if you want to modify any of those, you should always choose a dedoexed custom ROM.
Steps to follow:
1) Download xUltimate - Download
2) Run Main.exe
3) Press N to continue
4) Press Y to continue
5) You should get a complete menu
6) Connect phone to PC in USB Debugging Mode
7) Run Option 1
8) Run Option 2
9) Run Option 3
10) Run Option 4
11) You Will now have deodexed apps and framework files in done_app and done_frame folders.
12) Copy these folders where you have your adb setup.
13) Run the following Code
Code:
adb -d shell "mount -o remount,rw /dev/block/stl6 /system"
adb -d shell "stop"
adb -d shell "rm /system/app/*.apk"
adb -d shell "rm /system/app/*.odex"
adb -d shell "rm /system/framework/*.jar"
adb -d shell "rm /system/framework/*.odex"
adb -d push done_app /system/app/
adb -d push done_frame /system/framework/
adb reboot
14) Your phone should reboot successfully, and you now have a deodexed ROM.
Clean ROM
The following list of files you can delete to clean ROM
1) BuddiesNow
2) Dlna
3) DualClock
4) FlashSVGPlayer
5) HTMLViewer
6) InfoAlarm
7) InputEventApp
8) Layar-samsung
9) Maps
10) MobileTrackerEngineTwo
11) MobileTrackerUI
12) Protips
13) SamsungApps
14) SamsungWidget_CalendarClock
15) SamsungWidget_FeedAndUpdate
16) SamsungWidget_ProgramMonitor
17) SamsungWidget_StockClock
18) Street
19) UNAService
20) UnifiedInbox
21) VoiceRecorder
22) wipereceiver
23) WriteandGo
5) Kernel Basics​
dhirend_6d said:
What Is a Kernel?​
The UNIX kernel is the software that manages the user program's access to the systems hardware and software resources. These resources range from being granted CPU time, accessing memory, reading and writing to the disk drives, connecting to the network, and interacting with the terminal or GUI interface. The kernel makes this all possible by controlling and providing access to memory, processor, input/output devices, disk files, and special services to user programs.
Kernel Services
The basic UNIX kernel can be broken into four main subsystems:
Process Management
Memory Management
I/O Management
File Management
These subsystems should be viewed as separate entities that work in concert to provide services to a program that enable it to do meaningful work. These management subsystems make it possible for a user to access a database via a Web interface, print a report, or do something as complex as managing a 911 emergency system. At any moment in the system, numerous programs may request services from these subsystems. It is the kernel's responsibility to schedule work and, if the process is authorized, grant access to utilize these subsystems. In short, programs interact with the subsystems via software libraries and the systems call interface. We'll start by looking at how the UNIX kernel comes to life by way of the system initialization process.
System Initialization​
System initialization (booting) is the first step toward bringing your system into an operational state. A number of machine-dependent and machine-independent steps are gone through before your system is ready to begin servicing users. At system startup, there is nothing running on the Central Processing Unit (CPU). The kernel is a complex program that must have its binary image loaded at a specific address from some type of storage device, usually a disk drive. The boot disk maintains a small restricted area called the boot sector that contains a boot program that loads and initializes the kernel. You'll find that this is a vendor specific procedure that reflects the architectural hardware differences between the various UNIX vendor platforms. When this step is completed, the CPU must jump to a specific memory address and start executing the code at that location. Once the kernel is loaded, it goes through its own hardware and software initialization.
Kernel Mode​
The operating system, or kernel, runs in a privileged manner known as kernel mode. This mode of operation allows the kernel to run without being interfered with by other programs currently in the system. The microprocessor enforces this line of demarcation between user and kernel level mode. With the kernel operating in its own protected address space, it is guaranteed to maintain the integrity of its own data structures and that of other processes. (That's not to say that a privileged process could not inadvertently cause corruption within the kernel.) These data structures are used by the kernel to manage and control itself and any other programs that may be running in the system. If any of these data structures were allowed to be accidentally or intentionally altered, the system could quickly crash. Now that we have learned what a UNIX kernel is and how it is loaded into the system, we are ready to take a look at the four UNIX subsystems Process Management, Memory Management, Filesystem Management and I/O Management.
Process Management​
The Process Management subsystem controls the creation, termination, accounting, and scheduling of processes. It also oversees process state transitions and the switching between privileged and nonprivileged modes of execution. The Process Management subsystem also facilitates and manages the complex task of the creation of child processes.
A simple definition of a process is that it is an executing program. It is an entity that requires system resources, and it has a finite lifetime. It has the capability to create other processes via the system call interface. In short, it is an electronic representation of a user's or programmer's desire to accomplish some useful piece of work. A process may appear to the user as if it is the only job running in the machine. This "sleight of hand" is only an illusion. At any one time a processor is only executing a single process.
Process Structure​
A process has a definite structure (see Figure 19.1). The kernel views this string of bits as the process image. This binary image consists of both a user and system address space as well as registers that store the process's data during its execution. The user address space is also known as the user image. This is the code that is written by a programmer and compiled into an ".o " object file. An object file is a file that contains machine language code/data and is in a format that the linker program can use to then create an executable program.
Diagram of process areas.​
The user address space consists of five separate areas: Text, Data, Bss, stack, and user area.
Text Segment The first area of a process is its text segment. This area contains the executable program code for the process. This area is shared by other processes that execute the program. It is therefore fixed and unchangeable and is usually swapped out to disk by the system when memory gets too tight.
Data Area The data area contains both the global and static variables used by the program. For example, a programmer may know in advance that a certain data variable needs to be set to a certain value. In the C programming language, it would look like:
Code:
int x = 15;
If you were to look at the data segment when the program was loaded, you would see that the variable x was an integer type with an initial value of 15.
Bss Area The bss area, like the data area, holds information for the programs variables. The difference is that the bss area maintains variables that will have their data values assigned to them during the programs execution. For example, a programmer may know that she needs variables to hold certain data that will be input by a user during the execution of the program.
Code:
int a,b,c; // a,b and c are variables that hold integer values.
char *ptr; // ptr is an unitialized character pointer.
The program code can also make calls to library routines like malloc to obtain a chunk of memory and assign it to a variable like the one declared above.
Stack Area The stack area maintains the process's local variables, parameters used in functions, and values returned by functions. For example, a program may contain code that calls another block of code (possibly written by someone else). The calling block of code passes data to the receiving block of code by way of the stack. The called block of code then process's the data and returns data back to the calling code. The stack plays an important role in allowing a process to work with temporary data.
User Area The user area maintains data that is used by the kernel while the process is running. The user area contains the real and effective user identifiers, real and effective group identifiers, current directory, and a list of open files. Sizes of the text, data, and stack areas, as well as pointers to process data structures, are maintained. Other areas that can be considered part of the process's address space are the heap, private shared libraries data, shared libraries, and shared memory. During initial startup and execution of the program, the kernel allocates the memory and creates the necessary structures to maintain these areas.
The user area is used by the kernel to manage the process. This area maintains the majority of the accounting information for a process. It is part of the process address space and is only used by the kernel while the process is executing(see Figure 19.2). When the process is not executing, its user area may be swapped out to disk by the Memory Manager. In most versions of UNIX, the user area is mapped to a fixed virtual memory address. Under HP-UX 10.X, this virtual address is 0x7FFE6000. When the kernel performs a context switch (starts executing a different process) to a new process, it will always map the process's physical address to this virtual address. Since the kernel already has a pointer fixed to this location in memory, it is a simple matter of referencing the current u pointer to be able to begin managing the newly switched in process. The file /usr/include/sys/user.h contains the user area's structure definition for your version of UNIX.
Diagram of kernel address space.​
Process Table The process table is another important structure used by the kernel to manage the processes in the system. The process table is an array of process structures that the kernel uses to manage the execution of programs. Each table entry defines a process that the kernel has created. The process table is always resident in the computer's memory. This is because the kernel is repeatedly querying and updating this table as it switches processes in and out of the CPU. For those processes that are not currently executing, their process table structures are being updated by the kernel for scheduling purposes. The process structures for your system are defined in /usr/include/sys/proc.h.
Fork Process The kernel provides each process with the tools to duplicate itself for the purpose of creating a new process. This new entity is termed a child process. The fork() system call is invoked by an existing process (termed the parent process) and creates a replica of the parent process. While a process will have one parent, it can spawn many children. The new child process inherits certain attributes from its parent.
Process Run States​
A process moves between several states during its lifetime, although a process can only be in one state at any one time. Certain events, such as system interrupts, blocking of resources, or software traps will cause a process to change its run state. The kernel maintains queues in memory that it uses to assign a process to based upon that process's state. It keeps track of the process by its user ID.
UNIX version System V Release 4 (SVR4) recognizes the following process run states:
Code:
- SIDLE This is the state right after a process has issued
a fork() system call. A process image has yet to be copied into memory.
- SRUN The process is ready to run and is waiting to be executed by the CPU.
- SONPROC The process is currently being executed by the CPU.
- SSLEEP The process is blocking on an event or resource.
- SZOMB The process has terminated and is waiting on
either its parent or the init process to allow it to completely exit.
- SXBRK The process is has been switched out so that another process can be executed.
- SSTOP The process is stopped.[/COLOR]
When a process first starts, the kernel allocates it a slot in the process table and places the process in the SIDL state. Once the process has the resources it needs to run, the kernel places it onto the run queue. The process is now in the SRUN state awaiting its turn in the CPU. Once its turn comes for the process to be switched into the CPU, the kernel will tag it as being in the SONPROC state. In this state, the process will execute in either user or kernel mode. User mode is where the process is executing nonprivileged code from the user's compiled program. Kernel mode is where kernel code is being executed from the kernel's privileged address space via a system call.
At some point the process is switched out of the CPU because it has either been signaled to do so (for instance, the user issues a stop signal--SSTOP state) or the process has exceeded its quota of allowable CPU time and the kernel needs the CPU to do some work for another process. The act of switching the focus of the CPU from one process to another is called a context switch. When this occurs, the process enters what is known as the SXBRK state. If the process still needs to run and is waiting for another system resource, such as disk services, it will enter the SSLEEP state until the resource is available and the kernel wakes the process up and places it on the SRUN queue. When the process has finally completed its work and is ready to terminate, it enters the SZOMB state. We have seen the fundamentals of what states a process can exist in and how it moves through them. Let's now learn how a kernel schedules a process to run.
Process Scheduler​
Most modern versions of UNIX (for instance, SVR4 and Solaris 2.x) are classified as preemptive operating systems. They are capable of interrupting an executing a process and "freezing" it so that the CPU can service a different process. This obviously has the advantage of fairly allocating the system's resources to all the processes in the system. This is one goal of the many systems architects and programmers who design and write schedulers. The disadvantages are that not all processes are equal and that complex algorithms must be designed and implemented as kernel code in order to maintain the illusion that each user process is running as if it was the only job in the system. The kernel maintains this balance by placing processes in the various priority queues or run queues and apportioning its CPU time-slice based on its priority class (Real-Time versus Timeshare).
Memory Management​
Random access memory (RAM) is a very critical component in any computer system. It's the one component that always seems to be in short supply on most systems. Unfortunately, most organizations' budgets don't allow for the purchase of all the memory that their technical staff feel is necessary to support all their projects. Luckily, UNIX allows us to execute all sorts of programs without, what appears at first glance to be, enough physical memory. This comes in very handy when the system is required to support a user community that needs to execute an organization's custom and commercial software to gain access to its data.
Memory chips are high-speed electronic devices that plug directly into your computer. Main memory is also called core memory by some technicians. Ever heard of a core dump? (Writing out main memory to a storage device for post-dump analysis.) Usually it is caused by a program or system crash or failure. An important aspect of memory chips is that they can store data at specific locations called addresses. This makes it quite convenient for another hardware device called the central processing unit (CPU) to access these locations to run your programs. The kernel uses a paging and segmentation arrangement to organize process memory. This is where the memory management subsystem plays a significant role. Memory management can be defined as the efficient managing and sharing of the system's memory resources by the kernel and user processes.
Memory management follows certain rules that manage both physical and virtual memory. Since we already have an idea of what a physical memory chip or card is, we will provide a definition of virtual memory. Virtual memory is where the addressable memory locations that a process can be mapped into are independent of the physical address space of the CPU. Generally speaking, a process can exceed the physical address space/size of main memory and still load and execute.
The systems administrator should be aware that just because she has a fixed amount of physical memory, she should not expect it all to be available to execute user programs. The kernel is always resident in main memory and depending upon the kernel's configuration (tunable-like kernel tables, daemons, device drivers loaded, and so on), the amount left over can be classified as available memory. It is important for the systems administrator to know how much available memory the system has to work with when supporting his environment. Most systems display memory statistics during boot time. If your kernel is larger than it needs to be to support your environment, consider reconfiguring a smaller kernel to free up resources.
We learned before that a process has a well-defined structure and has certain specific control data structures that the kernel uses to manage the process during its system lifetime. One of the more important data structures that the kernel uses is the virtual address space (vas in HP-UX and as in SVR4. For a more detailed description of the layout of these structures, look at the vas.h or as.h header files under /usr/include on your system.).
A virtual address space exists for each process and is used by the process to keep track of process logical segments or regions that point to specific segments of the process's text (code), data, u_area, user, and kernel stacks; shared memory; shared library; and memory mapped file segments. Per-process regions protect and maintain the number of pages mapped into the segments. Each segment has a virtual address space segment as well. Multiple programs can share the process's text segment. The data segment holds the process's initialized and uninitialized (BSS) data. These areas can change size as the program executes.
The u_area and kernel stack contain information used by the kernel, and are a fixed size. The user stack is contained in the u_area; however, its size will fluctuate during its execution. Memory mapped files allow programmers to bring files into memory and work with them while in memory. Obviously, there is a limit to the size of the file you can load into memory (check your system documentation). Shared memory segments are usually set up and used by a process to share data with other processes. For example, a programmer may want to be able to pass messages to other programs by writing to a shared memory segment and having the receiving programs attach to that specific shared memory segment and read the message. Shared libraries allow programs to link to commonly used code at runtime. Shared libraries reduce the amount of memory needed by executing programs because only one copy of the code is required to be in memory. Each program will access the code at that memory location when necessary.
When a programmer writes and compiles a program, the compiler generates the object file from the source code. The linker program (ld) links the object file with the appropriate libraries and, if necessary, other object files to generate the executable program. The executable program contains virtual addresses that are converted into physical memory addresses when the program is run. This address translation must occur prior to the program being loaded into memory so that the CPU can reference the actual code.
When the program starts to run, the kernel sets up its data structures (proc, virtual address space, per-process region) and begins to execute the process in user mode. Eventually, the process will access a page that's not in main memory (for instance, the pages in its working set are not in main memory). This is called a page fault. When this occurs, the kernel puts the process to sleep, switches from user mode to kernel mode, and attempts to load the page that the process was requesting to be loaded. The kernel searches for the page by locating the per-process region where the virtual address is located. It then goes to the segments (text, data, or other) per-process region to find the actual region that contains the information necessary to read in the page.
The kernel must now find a free page in which to load the process's requested page. If there are no free pages, the kernel must either page or swap out pages to make room for the new page request. Once there is some free space, the kernel pages in a block of pages from disk. This block contains the requested page plus additional pages that may be used by the process. Finally the kernel establishes the permissions and sets the protections for the newly loaded pages. The kernel wakes the process and switches back to user mode so the process can begin executing using the requested page. Pages are not brought into memory until the process requests them for execution. This is why the system is referred to as a demand paging system.
The memory management unit is a hardware component that handles the translation of virtual address spaces to physical memory addresses. The memory management unit also prevents a process from accessing another process's address space unless it is permitted to do so (protection fault). Memory is thus protected at the page level. The Translation Lookaside Buffer (TLB) is a hardware cache that maintains the most recently used virtual address space to physical address translations. It is controlled by the memory management unit to reduce the number of address translations that occur on the system.
Input and Output Management​​
The simplest definition of input/output is the control of data between hardware devices and software. A systems administrator is concerned with I/O at two separate levels. The first level is concerned with I/O between user address space and kernel address space; the second level is concerned with I/O between kernel address space and physical hardware devices. When data is written to disk, the first level of the I/O subsystem copies the data from user space to kernel space. Data is then passed from the kernel address space to the second level of the I/O subsystem. This is when the physical hardware device activates its own I/O subsystems, which determine the best location for the data on the available disks.
The OEM (Original Equipment Manufacture) UNIX configuration is satisfactory for many work environments, but does not take into consideration the network traffic or the behavior of specific applications on your system. Systems administrators find that they need to reconfigure the systems I/O to meet the expectations of the users and the demands of their applications. You should use the default configuration as a starting point and, as experience is gained with the demands on the system resources, tune the system to achieve peak I/O performance.
UNIX comes with a wide variety of tools that monitor system performance. Learning to use these tools will help you determine whether a performance problem is hardware or software related. Using these tools will help you determine whether a problem is poor user training, application tuning, system maintenance, or system configuration. sar, iostat, and monitor are some of your best basic I/O performance monitoring tools.
1) sar The sar command writes to standard output the contents of selected cumulative activity counters in the operating system. The following list is a breakdown of those activity counters that sar accumulates.
* File access
* Buffer usage
* system call activity
* Disk and tape input/output activity
* Free memory and swap space
* Kernel Memory Allocation (KMA)
* Interprocess communication
* Paging
* Queue Activity
* Central Processing Unit (CPU)
* Kernel tables
* Switching
* Terminal device activity
2) iostat Reports CPU statistics and input/output statistics for TTY devices, disks, and CD-ROMs.
3) monitor Like the sar command, but with a visual representation of the computer state.
RAM I/O​
The memory subsystem comes into effect when the programs start requesting access to more physical RAM memory than is installed on your system. Once this point is reached, UNIX will start I/O processes called paging and swapping. This is when kernel procedures start moving pages of stored memory out to the paging or swap areas defined on your hard drives. (This procedure reflects how swap files work in Windows by Microsoft for a PC.) All UNIX systems use these procedures to free physical memory for reuse by other programs. The drawback to this is that once paging and swapping have started, system performance decreases rapidly. The system will continue using these techniques until demands for physical RAM drop to the amount that is installed on your system. There are only two physical states for memory performance on your system: Either you have enough RAM or you don't, and performance drops through the floor.
Memory performance problems are simple to diagnose; either you have enough memory or your system is thrashing. Computer systems start thrashing when more resources are dedicated to moving memory (paging and swapping) from RAM to the hard drives. Performance decreases as the CPUs and all subsystems become dedicated to trying to free physical RAM for themselves and other processes.
This summary doesn't do justice, however, to the complexity of memory management nor does it help you to deal with problems as they arise. To provide the background to understand these problems, we need to discuss virtual memory activity in more detail.
We have been discussing two memory processes: paging and swapping. These two processes help UNIX fulfill memory requirements for all processes. UNIX systems employ both paging and swapping to reduce I/O traffic and execute better control over the system's total aggregate memory. Keep in mind that paging and swapping are temporary measures; they cannot fix the underlying problem of low physical RAM memory.
Swapping moves entire idle processes to disk for reclamation of memory, and is a normal procedure for the UNIX operating system. When the idle process is called by the system again, it will copy the memory image from the disk swap area back into RAM.
On systems performing paging and swapping, swapping occurs in two separate situations. Swapping is often a part of normal housekeeping. Jobs that sleep for more that 20 seconds are considered idle and may be swapped out at any time. Swapping is also an emergency technique used to combat extreme memory shortages. Remember our definition of thrashing; this is when a system is in trouble. Some system administrators sum this up very well by calling it "desperation swapping."
Paging, on the other hand, moves individual pages (or pieces) of processes to disk and reclaims the freed memory, with most of the process remaining loaded in memory. Paging employs an algorithm to monitor usage of the pages, to leave recently accessed pages in physical memory, and to move idle pages into disk storage. This allows for optimum performance of I/O and reduces the amount of I/O traffic that swapping would normally require.
NOTE: Monitoring what the system is doing is easy with the ps command. ps is a "process status" command on all UNIX systems and typically shows many idle and swapped-out jobs. This command has a rich amount of options to show you what the computer is doing.
I/O performance management, like all administrative tasks, is a continual process. Generating performance statistics on a routine basis will assist in identifying and correcting potential problems before they have an impact on your system or, worst case, your users. UNIX offers basic system usage statistics packages that will assist you in automatically collecting and examining usage statistics.
You will find the load on the system will increase rapidly as new jobs are submitted and resources are not freed quickly enough. Performance drops as the disks become I/O bound trying to satisfy paging and swapping calls. Memory overload quickly forces a system to become I/O and CPU bound.
Filesystem Concept​
Filesystem is the collection place on disk device(s) for files. Visualize the filesystem as consisting of a single node at the highest level (ROOT) and all other nodes descending from the root node in a tree-like fashion (see Figure 19.5) . The second meaning will be used for this discussion, and Hewlett Packard's High-performance Filesystem will be used for technical reference purposes.
Diagram of a Android' s hierarchical filesystem.​
The superblock is the key to maintaining the filesystem. It's an 8 KB block of disk space that maintains the current status of the filesystem. Because of its importance, a copy is maintained in memory and at each cylinder group within the filesystem. The copy in main memory is updated as events transpire. The update daemon is the actual process that calls on the kernel to flush the cached superblocks, modified inodes, and cached data blocks to disk. The superblock maintains the following static and dynamic information about the
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6) Tools/Imp Download Links​
rickslick said:
Samsung USB drivers(no more kies) for 32bit and 64bit windows: Driver
Adb with ncessary dll : Click here
Flashing tools(odin+ops):click here
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7) Complete List of ROMs,Kernels for G3​
dhirend_6d said:
GINGERBREAD BASED ROMS : -
CYANOGENMOD 7 AND GINGERBREAD AOSP by Marcellusbe.
AOSP FROYO BASED ROMS : -
CYANOGENMOD 6.2 by Marcellusbe.
SAMSUNG FROYO BASED ROMS : -
1) G3MOD ROM by DharamG3 and G3Mod team.
2) KYRILLOS' ROM by Kyrillos13.
3) INDROID by Rudolf895, Arunmcops, Neeljinwala, Akash, Chirayu.
4) DUTCHMODS by Werker123.
5) DESTINY by Hodostamas.
6) KYORAROM by Hillbeast.
7) STYLOO' S AOSP STYLE ROM by Styloo.
8) LESTATIOUS ROM by The Dark Lestat.
9) GRIGORA ROM by RafayelG.
10) SUMEE ROM by Ash!sh.
11) STOCK DEODEXED ROOTED ROMS by DharamG3.
12) DHARAM' S ROM COLLECTION by DharamG3.
13) SAMSUNG STOCK FIRMWARES (WITHOUT BOOTLOADERS) by Kyrillos13.
14) IBREAD.NITESH by Niteshtak.
15) GREENMODS POX by Jazux, Akash, Pauri, s3th.g3ck0.
16) ATROM by Dpthakar.
17) SPEEDMOD ROM by Styloo and DharamG3.
18) RAFO' S ROM by RafayelG.
19) REAPER REVIVAL ROM by Jihaa.
20) APOCALYPSE by ARMVKDevs.
21) BURAK' S ROM by Burak721.
22) CYANOBROZZU MOD ROM by Superfancy97.
23) OUM ROM by Revant.
24) THE PEOPLE' S ROM by Shekhargreen.
25) GALACTIC BLUE ROM by Cdesai, Shubhamchamaria, Aarun.
26) PSYCHOTIK ROM by TotorLeTaureau
27) [KERNEL+ROM] APOLLO by Apollo5801
28) THE BLUE by Abhi0n0nakul.
KERNELS : -
KERNELS BY DHARAM AND TEAM G3MOD : -
1) G3Mod Kernels for Froyo.
2) G3Mod Kernels for CM 6.2.
All the kernels of G3Mod along with changelog and features can be found here.
KERNELS BY MARCELLUSBE : -
1) FuguMod 2.4 Beta 3 (JFS/REISERFS Supported), 800 Mhz Edition.
2) FuguMod 2.4 Beta 3 (JFS/REISERFS Supported), Standard Edition.
3) FuguMod 2.4 Beta 3, 800 MHz Edition.
4) FuguMod 2.4 Beta 3, Standard Edition.
5) FuguMod 2.2 Bleeding Edge Edition.
6) FuguMod 2.2 Standard Edition.
Link to all the above kernels here.
For features and changelog see here.
7) FuguMod Ultra.
KERNELS BY APOLLO5801 : -
Dual Boot kernel.
KERNELS BY GSAM101 : -
SAM' S KERNEL V0.1.
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8) FAQ For G3​
9) EPIC Fail Ideas for G3​
hillbeast said:
Seeing nobody has posted any real epic fail ideas, I will post one: I saw a guy wanting to post iOS to our phone. Now I can understand an iOS skin, but why would we want an OS that can't even handle multitasking properly and replace the glory of Android with Steve Jobs' locked down nutjob OS?
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Credits​
1) Android Basics
http://www.wikipedia.org/
http://developer.android.com/index.html
2) Galaxy 3 Features
www.gsmarena.com
3) Hardware
http://www.samsung.com/
http://www.atmel.com
4) ROM Basics/Tutorails
Flashing - BraveBuddy
dharamg3 said:
Credits​
rudolf895, jazux and sekhargreen for their tutorials and how-to's....
loads more too come...i will add as i add the context...
but thanks to all the developers doing the wonderful work for Galaxy 3
Click to expand...
Click to collapse
Damn this is going to be a long one because you reserved 10 posts good luck
jazux said:
Damn this is going to be a long one because you reserved 10 posts good luck
Click to expand...
Click to collapse
just wait and see..hoping to cover everything
dharamg3 said:
Credits​
rudolf895, jazux and sekhargreen for their tutorials and how-to's....
loads more too come...i will add as i add the context...
but thanks to all the developers doing the wonderful work for Galaxy 3
Click to expand...
Click to collapse
Hi,
It is good to get all the stuff at one place.
Let me know if any help needed.
sekhargreen said:
Hi,
It is good to get all the stuff at one place.
Let me know if any help needed.
Click to expand...
Click to collapse
sure, you can give me links here on what all can be added...
you can call the topic: "the ultimate guide for the galaxy 3"
vonuzu said:
you can call the topic: "the ultimate guide for the galaxy 3"
Click to expand...
Click to collapse
let me start off...it will take time to make it the ultimate
Android Basics Added to start off...Much More To Come
NICE WORK! Im definetly going to mail the xda newswriter about this
done in week you are going to be in news, for sure
This subject topic will be the most significant added value to this forum:
For the new members (sometime old once) that are joining the G3 revolution (and this is happing here), there is a need to provide them the basics before they can dive into elements such as: Custom ROM's, Kernel's...etc.
Myself as a junior user and others will greatly appreciate this new introduced topic.

Android terms and definitions

This isnt my work and this is the hardwork of Diablo67 and i thought that this would be useful in our forum. All thanks to Diablo67
I figured i would post this thread to help all of the new members and experienced understand the Android slang,there are actually a few i did'nt know the meaning of until i made this thread.I have compiled most of the terms,definitions and slang i could dig up,if theres anything i missed,let me know and i will add it to the thread,otherwise i will update this thread as new slang,terms and definitions are presented to me.
Apps2SD:A method of storing applications and cache on the device's microSD card.
ADB:Android Debug Bridge (adb) is a versatile command line tool that lets you communicate with an emulator instance or connected Android-powered device. It is a client-server program that includes three components:
•A client, which runs on your development machine. You can invoke a client from a shell by issuing an adb command. Other Android tools such as the ADT plugin and DDMS also create adb clients.
•A server, which runs as a background process on your development machine. The server manages communication between the client and the adb daemon running on an emulator or device.
•A daemon, which runs as a background process on each emulator or device instance.
Android:A Linux-based operating system for mobile devices such as HTC EVO.Versions are alphabetically codenamed after snacks: Donut, Eclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwich, Jelly Donut.
AMOLED:Active Matrix Organic Light Emitting Diode. Basically, a very colorful, bright, display found in some smartphones.
APK:Android application package file. Each Android application is compiled and packaged in a single file that includes all of the application's code (.dex files), resources, assets, and manifest file. The application package file can have any name but must use the .apk extension. For example: myExampleAppname.apk. For convenience, an application package file is often referred to as an ".apk".
Alpha:The alpha phase of the release life cycle is the first phase to begin software testing (alpha is the first letter of the Greek alphabet, used as the number 1). In this phase, developers generally test the software using white box techniques. Additional validation is then performed using black box or gray box techniques, by another testing team. Moving to black box testing inside the organization is known as alpha release.[1]
Alpha software can be unstable and could cause crashes or data loss. The exception to this is when the alpha is available publicly (such as a pre-order bonus), in which developers normally push for stability so that their testers can test properly. External availability of alpha software is uncommon in proprietary software. However, open source software, in particular, often have publicly available alpha versions, often distributed as the raw source code of the software.
The alpha phase usually ends with a feature freeze, indicating that no more features will be added to the software. At this time, the software is said to be a feature complete.
Boot Animation:Boot animation is a term for a graphical representation of the boot process of the operating system.
Boot animation can be a simple visualisation of the scrolling boot messages in the console, but it can also present graphics or some combinations of both.
Unlike splash screens, boot screen or boot animation is not necessarily designed for marketing purposes, but can be to enhance the experience of the user as eye candy, or provide the user with messages (with an added advantage of color coding facility) to diagnose the state of the system.
Bootloader:This small program's only job is to load other data and programs which are then executed from RAM.Often, multiple-stage boot loaders are used, during which several programs of increasing complexity load one after the other in a process of chain loading.
Bootloop:When your system recycles over and over without entering the main OS.
Beta: is the software development phase following alpha. It generally begins when the software is feature complete. Software in the beta phase will generally have many more bugs in it than completed software, as well as speed/performance issues. The focus of beta testing is reducing impacts to users, often incorporating usability testing. The process of delivering a beta version to the users is called beta release and this is typically the first time that the software is available outside of the organization that developed it.
The users of a beta version are called beta testers. They are usually customers or prospective customers of the organization that develops the software, willing to test the software without charge, often receiving the final software free of charge or for a reduced price.
Beta version software is often useful for demonstrations and previews within an organization and to prospective customers. Some developers refer to this stage as a preview, prototype, technical preview (TP), or early access.
Some software is kept in perpetual beta—where new features and functionality is continually added to the software without establishing a firm "final" release.
CPU:It stands for Central Processing Unit and handles all the complex mathematical formulas necessary to do everyday things like surfing the Internet.
Custom:Independent developers who like to customize their devices beyond the standard options provided often tend to release the fruits of their labor for the rest to enjoy, in form of custom ROMs.
Cache:A component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere. If requested data is contained in the cache (cache hit), this request can be served by simply reading the cache, which is comparatively faster. Otherwise (cache miss), the data has to be recomputed or fetched from its original storage location, which is comparatively slower. Hence, the greater the number of requests that can be served from the cache, the faster the overall system performance becomes.
CDMA:Mobile phone standards called cdmaOne, CDMA2000 (the 3G evolution of cdmaOne) and WCDMA (the 3G standard used by GSM carriers), which are often referred to as simply CDMA, and use CDMA as an underlying channel access method.
CIQ:Carrier IQ. A piece of preinstalled software that runs with elevated access in the background of portable devices by default and records everything. Potentially can be exploited to steal information.
Dual Core:A dual core processor is a central processing unit (CPU) that has two separate cores on the same die, each with its own cache. It essentially is two microprocessors in one. This type of CPU is widely available from many manufacturers. Other types of multi-core processors also have been developed, including quad-core processors with four cores each, hexa-core processors with six, octa-core processors with eight and many-core processors with an even larger number of cores.
Dalvik:The Android platform's virtual machine. The Dalvik VM is an interpreter-only virtual machine that executes files in the Dalvik Executable (.dex) format, a format that is optimized for efficient storage and memory-mappable execution.
Dalvik Cache:Writable cache that contains the optimized bytecode of all apk files (apps) on your Android device. Having the information in it's own cache makes applications load faster and perform better.
EXT2:The ext2 or second extended filesystem is a file system for the Linux kernel. It was initially designed by Rémy Card as a replacement for the extended file system (ext).
ext2 was the default filesystem in several Linux distributions, including Debian and Red Hat Linux, until supplanted more recently by ext3, which is almost completely compatible with ext2 and is a journaling file system. ext2 is still the filesystem of choice for flash-based storage media (such as SD cards, and USB flash drives) since its lack of a journal minimizes the number of writes and flash devices have only a limited number of write cycles. Recent kernels, however, support a journal-less mode of ext4, which would offer the same benefit along with a number of ext4-specific benefits.
EXT3:Third extended filesystem, is a journaled file system that is commonly used by the Linux kernel. It is the default file system for many popular Linux distributions, including Debian. Stephen Tweedie first revealed that he was working on extending ext2 in Journaling the Linux ext2fs Filesystem in a 1998 paper and later in a February 1999 kernel mailing list posting, and the filesystem was merged with the mainline Linux kernel in November 2001 from 2.4.15 onward.Its main advantage over ext2 is journaling, which improves reliability and eliminates the need to check the file system after an unclean shutdown. Its successor is ext4.
EXT4:It was born as a series of backward compatible extensions to ext3, many of them originally developed by Cluster File Systems for the Lustre file system between 2003 and 2006, meant to extend storage limits and add other performance improvements.However, other Linux kernel developers opposed accepting extensions to ext3 for stability reasons,and proposed to fork the source code of ext3, rename it as ext4, and do all the development there, without affecting the current ext3 users. This proposal was accepted, and on 28 June 2006, Theodore Ts'o, the ext3 maintainer, announced the new plan of development for ext4.
FC/FC's:Short for "force close," meaning an app that has crashed.
Fastboot:A diagnostic protocol used primarily to modify the flash filesystem in Android smartphones from another computer over a USB connection. It is part of the Android Debug Bridge library.
Utilizing the Fastboot protocol requires that the device be started in a boot loader or Second Program Loader mode in which only the most basic hardware initialization is performed. After enabling the protocol on the device itself it will accept any command sent to it over USB via a command line. Some of most commonly used fastboot commands include:
•flash - Overwrites a partition in flash with a binary image stored on the host computer.
•erase - Erases a partition in flash.
•reboot - Reboots the device into the either the main operating system or the system recovery partition.
•devices - Displays a list of all devices (with Serial #) connected to the host computer.
Flashing:The ROM memory used in smartphones and tablets etc. is often same as flash memory found in SD cards and USB flash drives, simply optimized for better speed and performance while running the operating system.
Hotspot:A spot that offers Internet access over a wireless local area network through the use of a router connected to a link to an Internet service provider. Hotspots typically use Wi-Fi technology.You can connect wifi campatible devices to it.
HDMI:High-Definition Multimedia Interface) is a compact audio/video interface for transmitting encrypted uncompressed digital data.It is a digital alternative to consumer analog standards, such as radio frequency (RF) coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA (also called D-sub or DE-15F). HDMI connects digital audio/video sources (such as set-top boxes, DVD players, HD DVD players, Blu-ray Disc players, AVCHD camcorders, personal computers (PCs), video game consoles (such as the PlayStation 3 and Xbox 360), AV receivers, tablet computers, and mobile phones) to compatible digital audio devices, computer monitors, video projectors, and digital televisions.
Hboot:It’s mainly responsible for checking and initializing the hardware and starting the phone’s software. It can also be used for flashing official software releases, as well as a few other things. HBoot can be compared to the BIOS on a computer.
HAVS:a control system that dynamically adjusts the voltage based on CPU load. This has proven to be a battery saver, but it can actually have the opposite effect when multiple control systems are operating (like setCPU).
JIT:The Just-in-Time Compiler. Released with Android 2.2, it's a method of greatly speeding up apps in Android on the software side.
Kang:Someone writes a code,someone else modifies the code to make their own release,its concidered a kang release.
Kernel:A kernel is a layer of code that allows the OS and applications to interface with your phone's hardware. The degree in which you can access your phone's hardware features depends on the quality of code in the kernel. The homebrew (rooting) community for HTC has made several kernel code improvements that give us additional features from our hardware that the stock kernel does not. When you flash a custom ROM, you automatically get a kernel. But you can also flash a standalone kernel ROM on top of the existing one, effectively overwriting it. These days, the difference in custom kernels is less about new features and more about alternate configurations. Choosing a custom kernel is basically choosing one that works best with your ROM.
Launcher:Collectively, the part of the Android user interface on home screens that lets you launch apps, make phone calls, etc. Is built in to Android, or can be purchased in the Android Market.
LCD Densityixel density is a measurement of the resolution of devices in various contexts; typically computer displays, image scanners, and digital camera image sensors.
First of all you need to understand that the Android User Interface uses something called a "display independent pixel" or a "dip" (yes, it's confusing because the density settings are in "dots per inch" or "dpi" which are considered the same as "ppi" or "pixels per inch" as well).
The default LCD Density setting on Android is 160 dpi. As far as the operating system is concerned 1 dip @ 160 dpi = 1 screen pixel. It doesn't mean that's actually true, but you've gotta start somewhere. In my opinion it would have been a lot nicer if they'd chosen 100 dpi because then it would be an easy percentage thing, but they didn't so we're stuck with this formula.
Mod:The act of modifying a piece of hardware or software or anything else for that matter, to perform a function not originally conceived or intended by the designer.
Nandroid:To backup the current running rom.
Nightly:A build that is performed at the end of each day of development. If you use a continuous integration server, it will generally be configured to build the code and run the unit tests on every check in. At the end of each day you may want to run more extensive tests, regression test and integration tests for example, which take too long to run on each check in and these would be triggered after the nightly build. If you have a full continuously delivery pipeline the nightly build may also be used to deploy the built code to environments for user testing.
Open GL:An open source 3D graphics library used in many devices, including Android devices.
Open & Closed Betaevelopers release either a closed beta or an open beta; closed beta versions are released to a select group of individuals for a user test and are invitation only, while open betas are from a larger group to the general public and anyone interested. The testers report any bugs that they find, and sometimes suggest additional features they think should be available in the final version.
Overclock:To increase the speed of your CPU.
Partition:The phone's internal memory (not the SD card) is solid-state (flash) memory, AKA NAND. It can be partitioned much like a normal hard drive can be partitioned. The bootloader exists in its own partition. Recovery is another partition; radio, system, cache, etc are all partitions.
Here are the standard partitions on an Android phone:
/misc - not sure what this is for.
/boot - bootloader, kernel
/recovery - holds the recovery program (either clockworkmod or RA recovery for a rooted Evo)
/system - operating system goes here: Android, Sense, boot animation, Sprint crapware, busybox, etc
/cache - cached data from OS usage
/data - user applications, data, settings, etc.
The below partitions are not android-specific. They are tied to the hardware of the phone, but the kernel may have code allowing Android to interact with said hardware.
/radio - the phone's radio firmware, controls cellular, data, GPS, bluetooth.
/wimax - firmware for Sprint's flavor of 4G, WiMax.
PRL:The Preferred Roaming List, basically a way of telling your phone which towers to connect to first.
RUU:a complete software package released by HTC, it can contain many things they are trying to update. Radio, ROM, bootloader, etc... Installing an ruu is like installing an image on a hard drive it wipes the phone and installs the image. It will wipe everything data and all so if you install one be prepared.
Recovery Mode:A small separate operating mode you can boot your device into, used for device administration. Two popular custom recovery modes are Amon Ra and Clockwork.
Rom/Firmware:Read-Only Memory and technically speaking, it refers to the internal storage of a device, which is supposed to contain the operating system instructions that needn’t be modified at all during the device’s normal operation.
Radios:On the HTC side of things,the radios persist of:
•WiFi, which operates at 2.4-5ghz depending on what channel it's running
•Cellular/3G, which carries voice and data
•4G/WiMAX, which only carries data
•GPS, which is receive-only
•Bluetooth, which talks to WiiMotes and headsets
Flashing a radio means updating the code that controls the phones way of sending and recieving a signal.
RamRandom Access Memory) A group of memory chips, typically of the dynamic RAM (DRAM) type, which function as the computer's primary workspace. When personal computers first came on the market in the late 1970s, 64KB (64 kilobytes) of RAM was the upper limit. Today, 64MB (64 megabytes) of SDRAM is entry level for a desktop computer, a thousand times as much (see SDRAM).
The "random" in RAM means that the contents of each byte of storage in the chip can be directly accessed without regard to the bytes before or after it. This is also true of other types of memory chips, including ROMs and PROMs. However, unlike ROMs and PROMs, RAM chips require power to maintain their content, which is why you must save your data onto disk before you turn the computer off. To learn about the types of RAM chips and how to upgrade your memory, see memory module. To learn how memory is used to process data, see computer or memory. See also dynamic RAM and static RAM.
Recovery:RecoverySystem contains methods for interacting with the Android recovery system (the separate partition that can be used to install system updates,wipe user data,etc).
Root:The first level of a folder.
Rooting:A process allowing users of mobile phones, tablet PCs, and other devices running the Android operating system to attain privileged control (known as "root access") within Android's subsystem. Rooting is often performed with the goal of overcoming limitations that carriers and hardware manufacturers put on some devices, resulting in the ability to alter or replace system applications and settings, run specialized apps that require administrator-level permissions, or perform other operations that are otherwise inaccessible to a normal Android user. Rooting is analogous to jailbreaking devices running the Apple iOS operating system or the Sony PlayStation 3. On Android, rooting can also facilitate the complete removal and replacement of the device's operating system.
SBCthe ability to charge your battery beyond the default safe limit). The concept is similar to overclocking a processor: you're overriding the safety limits established to achieve additional performance. The benefit here is that you may gain more use of your battery per charge. The drawback is that you can damage the battery and significantly reduce its longevity. Some kernels claim they are using a safe technique to prevent battery damage. Just be aware of the potential risks.
Sideloading:It means installing applications without using the official Android Market.
Splash Screen:A splash screen is an image that appears while android is loading.Splash screens cover the entire screen or simply a rectangle near the center of the screen. The splash screens of operating systems and some applications that expect to be run full-screen usually cover the entire screen.
Superuser/SU:On many computer operating systems, the superuser is a special user account used for system administration. Depending on the operating system, the actual name of this account might be: root, administrator or supervisor.
Normal work on such a system is done using ordinary user accounts, and because these do not have the ability to make system-wide changes any viruses and other malware - or simple user errors - do not have the ability to adversly affect a whole system. In organizations, administrative privileges are often reserved for authorized experienced individuals.
Script:The Scripting Layer for Android (abridged as SL4A, and previously named Android Scripting Environment or ASE) is a library that allows the creation and running of scripts written in various scripting languages directly on Android devices. SL4A is designed for developers and is still alpha quality software.
These scripts have access to many of the APIs available to normal Java Android applications, but with a simplified interface. Scripts can be run interactively in a terminal, in the background, or via Locale.
SDKSDK or "devkit") is typically a set of software development tools that allows for the creation of applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar platform.
Stock:This is the operating system in its default form, without any modifications made to it except for any device-specific support required to run it on the particular device.
S-On:Security on,means no acces to the phones operating system.
S-Off:Security was exploited,now have access to the operating system.
Tethering:Means sharing the Internet connection of an Internet-capable mobile phone with other devices. This sharing can be offered over a wireless LAN (Wi-Fi), Bluetooth, or by physical connection using a cable. In the case of tethering over wireless LAN, the feature may be branded as a mobile hotspot.The Internet-connected mobile phone acts as a portable router when providing tethering services to others.
Userspace(Governor):This governor, exceptionally rare for the world of mobile devices, allows any program executed by the user to set the CPU's operating frequency. This governor is more common amongst servers or desktop PCs where an application (like a power profile app) needs privileges to set the CPU clockspeed.
Underclock:To reduce the speed of your CPU.
Undervolt:Undervolting means taking some of the voltage from the CPU which in return gives a longer battery life and lower temperature during intensive use of the CPU.
USB:Stands for Universal Serial Bus. Is a method of connecting devices to a computer. Most smartphones now use microUSB cables to charge and sync.
Updater Script:When Android devices install updates via 'update.zip' files using recovery mode they have to perform a wide range of functions on files and permissions. Instead of using a minimal shell such as {b,d,c}sh the Android designers decided to create a small functional language that can be extended by device manufacturers if necessary. Since the Android "Donut" release (v1.6) the scripting language is called Edify and is defined primarily in the bootable/recovery/{edify,edifyscripting,updater} directories of the Android source-code tree.
Wireless N:Wireless N technology increases wireless internet connection. Wireless 'N' routers also work with Wireless 'G' and 'B' wireless adapters.
WiiMaxWorldwide Interoperability for Microwave Access) is a communication technology for wirelessly delivering high-speed Internet service to large geographical areas.
YAFFS:Yaffs1 is the first version of this file system and works on NAND chips that have 512 byte pages + 16 byte spare (OOB;Out-Of-Band) areas.[clarification needed] These older chips also generally allow 2 or 3 write cycles per page,which YAFFS takes advantage of - i.e. dirty pages are marked by writing to a specific spare area byte.
Newer NAND flash chips have larger pages, 2048 bytes + 64 bytes spare areas, and stricter write requirements.Each page within an erase block (128 kilobytes) must be written to in sequential order, and each page must be written only once.YAFFS2 was designed to accommodate these newer chips.YAFFS2 is based on the YAFFS1 source code,with the major difference being that internal structures are not fixed to assume 512 byte sizing,and a block sequence number is placed on each written page. In this way older pages can be logically overwritten without violating the "write once" rule.[clarification needed]
YAFFS is a robust log-structured file system that holds data integrity as a high priority.A secondary YAFFS goal is high performance.YAFFS will typically outperform most alternatives.It is also designed to be portable and has been used on Linux, WinCE, pSOS, eCos,ThreadX and various special-purpose OSes.A variant 'YAFFS/Direct' is used in situations where there is no OS, embedded OSes and bootloaders: it has the same core filesystem but simpler interfacing to the OS and NAND flash hardware.
Zipalign: An archive alignment tool introduced first time with 1.6 Android SDK (software development kit). It optimizes the way an Android application package (APK) is packaged. Doing so enables the Android operating system to interact with the application more efficiently, and hence has the potential to make the application and overall the whole system much faster. Execution time is minimized for zipaligned applications, resulting is lesser amount of RAM consumption when running the APK.
original thread - http://forum.xda-developers.com/showthread.php?t=1466228
http://forum.xda-developers.com/showthread.php?t=1510729

Researchers warn over OTA Exploits of Baseband Processors (radio firmware)

Thom Holwerda at Real-Time Embedded OS specialized website OSnews reports about vulnerabilities that lurk in closed-sourced radio chips.
The second operating system hiding in every mobile phone
The insecurity of baseband software is not by error; it's by design. The standards that govern how these baseband processors and radios work were designed in the '80s, ending up with a complicated codebase written in the '90s - complete with a '90s attitude towards security. For instance, there is barely any exploit mitigation, so exploits are free to run amok. What makes it even worse, is that every baseband processor inherently trusts whatever data it receives from a base station (e.g. in a cell tower). Nothing is checked, everything is automatically trusted. Lastly, the baseband processor is usually the master processor, whereas the application processor (which runs the mobile operating system) is the slave.
(...)
With this in mind, security researcher Ralf-Philipp Weinmann of the University of Luxembourg set out to reverse engineer the baseband processor software of both Qualcomm and Infineon, and he easily spotted loads and loads of bugs, scattered all over the place, each and every one of which could lead to exploits - crashing the device, and even allowing the attacker to remotely execute code. Remember: all over the air. One of the exploits he found required nothing more but a 73 byte message to get remote code execution. Over the air.
Click to expand...
Click to collapse
Source, via HN
Comments at HN are also worth reading, I think.
Do note, that the study run on some old generation of MSM chips.
Here is a counter argument for instance:
Comment by OsQar
by OsQar on Wed 13th Nov 2013 09:51 UTC
I'm not a security expert at all, but I've been working on mobile radio access technologies for several years, so I feel quite confident to say that some or your claims are wrong. E.g:
"The standards that govern how these baseband processors and radios work were designed in the '80s, ending up with a complicated codebase written in the '90s - complete with a '90s attitude towards security."
Well, GSM's baseband was developed from late 80's to early 90's, UMTS' from late 90's to early 00's, and LTE's can be now be considered almost finished. I know that GSM is not secure at all now (it was when it was released, but now it has been cracked), but I'm not so sure about UMTS (CDMA is very hard to demodulate, so cracking is even worse) and LTE (OFDMA is quite a headache).
"What makes it even worse, is that every baseband processor inherently trusts whatever data it receives from a base station (e.g. in a cell tower). Nothing is checked, everything is automatically trusted."
This is NOT TRUE. At all. Even from GSM times. Handheld devices run a bunchload of ID checks to know what basestation is sending data; and basestations also carefully allocate and check mobile ID's. This is especially true in UMTS (where you have to discriminate interferring users by using pseudorandom codes) and LTE (where you even need angle-of-arrival information to reach more users).
So, I'm not claiming that mobile basebands are inherently secure, but they're definitively not based on 80's security technology.
On the other hand, I agree with your viewpoint that the closed implementations and the huge standards are not the best way to allow the community to check for security bugs. But manufacturers are the main supporters of actual standardization bodies, so it's quite complicated to fight against it.
Click to expand...
Click to collapse

new open source library ogles_gpgpu: GPGPU for Android and iOS using OpenGL ES 2.0

(please note: I would like to post this to the developer forum, but since I just registered, I'm not allowed to do so. furthermore, I'm not allowed to post direct links (see below))
I would like to announce a new library for GPU-based processing on mobile systems – ogles_gpgpu.
As many of you know, it is often beneficial in terms of performance and energy efficiency to execute certain processing tasks on the GPU instead of the CPU. This is especially the case for image processing tasks. ogles_gpgpu enables fast and portable, GPU-powered processing by using OpenGL ES 2.0 shaders.
Since transferring data to and from the GPU is often a bottleneck for GPU processing, platform-specific fast texture access is also implemented. The library is written in well documented, clear C++ code. An interface for Android systems via JNI is provided. Example applications show how to use this library. All code is LGPL licensed.
There are several scenarios on how to use this library: You can for example pass image data (or arbitrary byte data) to ogles_gpgpu, which creates an OpenGL texture from it. You can then process it on the GPU by applying a series of filters (OpenGL shaders) on it. This kind of rendering happens off-screen. Afterwards, you can lock the result data and obtain a pointer to it. You can then copy this data for future processing or directly analyze or modify it. Another possible scenario is to directly pass an OpenGL texture ID as input for ogles_gpgpu. This is for example beneficial if you can obtain camera frames as OpenGL texture from the camera API of your target platform (both Android and iOS allow this and example projects or provided for this). Now ogles_gpgpu can directly run the filters on this camera frame texture. This can happen off-screen or optionally on-screen, which means that the result image is also displayed to a render surface. After processing on the GPU side, you can access the result data again as described in the first scenario. By this, you can do further CPU-based processing of the result data. This is for example necessary, if certain algorithms can not (efficiently) be implemented as OpenGL shaders.
At current development stage, there are not so many image processing filters implemented, yet, but this is about to change in the future. The most important thing is that a portable architecture for GPU-based processing is available, which allows fast texture access by using platform-specific optimizations.
You can check out the project on github: github.com/internaut/ogles_gpgpu
More information can be found on my personal website: mkonrad.net/projects/ogles_gpgpu.html
Thank you.

[Kernel][patch] Meltdown/Spectre processor (CPU sec vuln.) mitigation discussion

LineageOS / 3.4 kernel security vulnerability patch / change
Posting this here, since this is in everyone's interest to reduce attack surface to these kind of attacks to a minimum
Quoting:
https://blog.barkly.com/meltdown-spectre-patches-list-windows-update-help
Meltdown and Spectre Overview
Before we dive in, here's a quick recap of what Meltdown and Spectre are all about. For more in-depth details see our post, The Meltdown and Spectre CPU Bugs, Explained.
Meltdown (CVE-2017-5754)
Meltdown is a CPU vulnerability that allows a user mode program to access privileged kernel-mode memory. It affects all out-of-order Intel processors released since 1995 with the exception of Itanium and pre-2013 Atoms. A list of vulnerable ARM processors and mitigations is listed here. No AMD processors are affected by Meltdown.
Of the two bugs, Meltdown is the easier one to fix, and can largely be addressed with operating system updates.
Spectre (CVE-2017-5753, CVE-2017-5715)
Spectre isn't so much a specific vulnerability as it's a new class of attack. It's enabled by the unintended side effects of speculative execution (something processors do to speed things up by predicting what instructions they're about to recieve and executing them ahead of time).
There are two flavors of Spectre — variant 1 (bounds check bypass, CVE-2017-5753) and variant 2 (branch target injection, CVE-2017-5715). Both can potentially allow attackers to extract information from other running processes (ex: stealing login cookies from browsers).
Intel, ARM, and AMD processors are all reportedly affected by Spectre to some degree, and it poses significant patching problems. While operating system and browser updates have helped mitigate the risk of Spectre to some degree, experts agree the only true fix is a hardware update. As such, Spectre is likely to remain an issue for years to come.
Meltdown-Spectre-comparison-table.png
Source: SANS / Rendition Infosec. See the full presentation here
It's important to note that both vulnerabilities put information disclosure at risk. Neither are remote execution vulnerabilities — in other words, they don't allow attackers to run malware.
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Following Android's January 2018 security bulletin the following kernel change was rather eye-catching:
CVE-2017-13218 A-68266545* ID High High-precision timers
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Unfortunately (or luckily for us, security by obscurity) - these kind of kernel changes aren't easy to find for quite some time
It turns out the change is the following:
clocksource: arch_timer: make virtual counter access configurable
The changes to be applied are made in the file drivers/clocksource/arm_arch_timer.c fortunately at first glance it doesn't exist in 3.4 kernels,
unfortunately "Enable user access to the virtual counter" is still (already) there, namely:
arch/arm/include/asm/arch_timer.h
So:
I ask the kernel devs to try out (read: "port back") that change to the 3.4 kernel for the Note 3 (or well, referencing this - all Android devices running 3.4 based custom kernels)
P.S.:
the following important ashmem fix (preventing memory corruption) also potentially is applicable to the 3.4 kernel source:
staging: android: ashmem: fix a race condition in ASHMEM_SET_SIZE ioctl
I haven't built a Note 3 kernel since ... ever - so haven't tested that change and if the resulting kernel would boot,
so I can't say if there's any adverse effects when disabling user(space) access to the virtual counter, in any case security should supersede convenience or even functionality

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