Memory stored on external instead of internal - General Questions and Answers

i just thought about ROM's made to store memory on SD cards instead of being stored internaly. can anyone explain y it wouldnt work or y anyone hasnt done it yet?

also wanted to add, by doing this change of memory storage it would speed up the system by 50%. it would also be a + for people who play video games on their smart phones Zonia, Inotia, MMO's ect"""

An SD card, or any format of memory card for that matter, can only be used for the storage of data. It behaves like a hard disk. Data on it must be serially 'read' into a main memory buffer, before it can be accessed by your device's processor.
You can't replace 'real' memory with it or try to use it as real memory.

hijack562 said:
doing this change of memory storage it would speed up the system by 50%
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why?
10 characters

so cant you partition a sd card to be used as real memory? or can it be possible to compress real memory?
and why you ask? cuz it would be nice to play games on a smart phone that only comes with 200mb or less memory. but has a fairy decent processor

Too Slow
The reason they don't do that is because SD cards are MUCH slower than memory. the fastest SD cards (Class 10) only transfer data at 10 MB/s. Memory on the other hand transfers data in the range of gigabytes per second. Even if the memory used a very "slow" rate of 1GB/s that is still 100x faster than a SD card is.

really?? a class 10 only reads 10mb per sec?? dam thats slow...but isnt a sd card consider a soild state drive or not?

Take a close look at an SD card. It only has 9 pins on it. In standard mode two of them aren't used, leaving 7. After 1 x Chip Select, 1 x Power, 2 x Ground, and 1 x Clock, that leaves two pins - namely 1 x Data In and 1 x Data Out.
Not a 32 bit data/address bus like an x86 or ARM processor, but a single, one bit wide bus.
A byte of stored data comes out of the Data Out line as 8 bits, one at a time.
Commands to the card, to ask it to retrieve/store the data you want, have to be sent down the Command/Data In line the same way. Data to be written to the card goes in down the same Data In line the same way, again one bit at a time.
Even though the clock rate can, in theory, be wound up to 25Mhz, it is still a tedious process to get data in and out of the thing.
True solid state drives use the SATA interface, a different type of interface, still serial as above, but the clock rates are much, much higher allowing 1.5 to 6.0 GBit/s transfer rates.
Memory cards can be considered solid state drives, just damned slow ones.

Sorry if this isn't directed towards OP but since we are talking about SD cards anyways I thought I'd ask. Any way to tell what class your SD card is? I have a 16GB one so I'm assuming its class 10.

New cards have the class number on the label, as Class n, or as a capital 'C' with the class number in it.

Related

Peak Performance from Sd card.

I want to have maximum performance from my mini sd card.I heard that formatting it in an appropriate way would increase its performance.By performance i literally mean that the transfer rates are increased.Like when i am moving some big songs and transferring big fies via pc.
I had a magician before and it would take less time to copy a 650mb file than my hermes,
So any body tell me can i do anything to get higher transfer rates?
I mean fat ot fat32? And the allocation unit size?
I dont care if i have to sacrifice my space for performance
Have you found out anything about how to format your card or if there are any new drivers for better performance?
I'm on a Blackstone.
the program pocketmechanics let you benchmark sd cards and compare the result with other cards

Using SD CARD as RAM

Hey! Is there any possibility to create virtual memory on my HTC (p3600) like use SD card memory to create virtual memory?
It would be the slowest ram ever seen
so... what's the data transmition top velocity (how many mbps?(in MB please))
Is it really possible?
I think that if we want to, we can lol!
I just want to know how fast is the processing between a SD card and the HTC... like... if we can see movies, listen to music play 3D games at 60 fps (like duke nuken 3d) I think that we can create a Ram Virtual memory just like your mac/pc. Hmn... and if it's slow with a SD card... maybe try to use some internal memory... what do HTC (I'm refering to my HTC p3600) Ram have so special?
Nothing special, seems you are confusing RAM and Flash, they are completely different technologies, RAM is a volatile memory and fast by nature to work with CPU, flash is persistent but slow (compared to RAM) to work as storage; even if you could create a swap file to simulate RAM, if won't work at RAM speed so your device would become slow as hell.
More, RAM space (physical or emulated) is pretty dynamic, it does a lot of read/write all time, so if you emulate it, you'd need a storage device that can bear all that stress like hard disks, but if you use flash, cards would become unusable after a short time so I really doubt there's a program that emulates RAM for PocketPCs.
I'm thinking on xdandroid running from the sd card? can some one run all wm6.x from the sd making the phone have 16 gb of internal memory?

Readyboost and Surface microsd reader

Any one have luck getting ready boost working with the surface mico sd reader. I have a class 10 card that ready boost is working on a Win 8 pro machine via a sd card reader.
mattalter said:
Any one have luck getting ready boost working with the surface mico sd reader. I have a class 10 card that ready boost is working on a Win 8 pro machine via a sd card reader.
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Isn't readyboost mainly for booting up the computer. With the Surface being mainly on from standby mode, which is almost instant, not sure of the benefit. I have only cold booted my Surface a few times in the 2 weeks I have had it and that was mainly due to an update that required it.
Readyboost
I found this. Looks like RB is disabled when a SSD is present.
http://technet.microsoft.com/en-us/magazine/ff356869.aspx
ReadyBoost only caches disk drive activity, it's pointless with SSDs. You could write to the SSD faster than you could write to the SD card.
@netham45 hs it right. If you look at the error when trying to use RB on a device with a SSD, it tells you that the system drive is so fast that RB wouldn't help anything. The point of RB is to basically extend the SuperFetch cache, which lets you load programs faster by pre-loading their files into RAM based on what times of day you typically run them. On machines with a slow HD, this can be a huge speed boost (launching EVE Online, which has a footprint of over a gig, went from ~20 second on my XP install to ~8 when I installed Vista, even though the machine had less than 2GB of RAM). However, its effectiveness is limited on low-RAM systems, because Superfetch has to have some free RAM to use for the cache, and if all the RAM is in use then it can't help you. Enter ReadyBoost; reading Flash storage is a lot faster than reading most hard disks, so even though it's not nearly as fast as RAM it still hugely speeds up loading large amounts of data, especially across many files (almost zero access latency).
On a system with an SSD, Superfetch is still useful (the SSD is nowhere close to the speed of RAM), but Readyboost really isn't; a typical SD card or UMS device has a read speed somewhere in the range of 100-400 Mbps (USB2 caps out at 480Mbps, but many external devices can't come close to that). On the other hand, a SATA2 connection caps out at 3Gbps (more than 6x as fast) and some SSDs can already saturate those, which is why SATA3 exists (6Gbps). ReadyBoost isn't going to do a darn thing for the Surface.

[Q] SD Card Speed/Class Matters!!??

Hello Guyz. This is my first post on any kind of forum and let me go to my problem straight away.
I am using HTC Pico (Explorer) for the last one and half month or so. Obviously the problem is low internal memory. Have tried as many roms as possible to overcome this issue. Found JaggyRom 3.2.1 most suitable when using a2sdgui script and tried installing as many apps as possible. But there is also limit to it. I also tried other CM9/ICS/JB roms out there with int2ext/d2ext+ scripts to actually increase internal memory to 1GB. Even today, I tried Sense 4.0A Build#2 Ver 3 Final, but ultimately they're installed work fine from dev's point of view but my phone is dead slow n I recieve FC msgs alot.
Now my point is that I need to have a look of either ICS or Sense 4.0 but with greater internal memory. Dev guyz are doing great job facilitating nerds like me, but both of the above roms tend to make my phone dead SLOW and I get FC messages a lot many times, since all the data is moved to SD-EXT. Developers have claims of running these roms smooth, but plz put me wise here in this issue. I just wanted to ask a simple question:
1. Does my SD card's speed/class really matters? (btw I've 2GB microSD with 1GB SD-EXT partition, and I don't know its speed/class )
2. My HTC Explorer is rooted, super user capable (as I've learned alot during this one n a half month to do this )
3. Please suggest me what to do here (actually I'm tired of flashing ROMS now )
Regards.
1. The higher class is, the faster sd card is.
2-3. I'm on cm9 build #8(too lazy to update it ) with sdcard a-data class 10 with 1GB external partition using mounts2sd. Working fine .
Sent from my HTC Explorer A310e using xda app-developers app
Well, the answer to your question is kinda hard to understand, please read it carefully, as I spent time typing it here .
1/ Yes, card speed really matter, but it's not the class that matter. Class rating is for sequential write speed. For Android, what matters is random small-burst write speed. Read the first post of this thread http://forum.xda-developers.com/showthread.php?t=1005633. To successfully utilize your card, you must understand what you want to put on it.
An Android app normally have 3 parts: app (main apk), dalvik-cache, and data (your app's data like account, save game). app and dalvik will make use of sequential write/read speed, but data will benefit from random small-burst read/write speed.
Your internal memory is optimized for both type of read/write (that's why they're expensive like hell), while normally, SD cards are optimized for sequential read/write. Read again about the scripts you use, you will find that scripts that seem suitable for you have: app & dalvik on SD, data on internal. With data on internal, you will have a limit, because some apps use a lot of space for data.
Those scripts that make your internal memory become 1GB simply mount the SD-ext partition as internal memory, so everything is on SD cards, and the slow random write speed cripples your system.
Your best bet now is to try some configurable script like m2sd (I personally highly recommend it), have some patient setting it up, with app and dalvik on SD, leave data on internal, and you're good to go.
Use this link http://forum.xda-developers.com/showthread.php?t=1342387 to learn about m2sd if you're interested.
You should consider buying a fast card like Sandisk Ultra, they're not expensive. Remember to go with Sandisk (class 6 and up) when you're with Android. Some people also report that Samsung cards have great random write speed, and they're on sale more often than Sandisk (just avoid the Plus series). When you buy cards, always look for some benchmark about it's random 4k write speed.
And even with a fast card, I think you should still leave data on internal, data on SD put a heavy burden on your card, which can decrease it's lifespan soon.
I hope you read to this line, the post cost me more than 30 minutes . I just want to help :highfive:.
I attached the m2sd zip that I am using. And if you trust me, try MiniCM9 http://forum.xda-developers.com/showthread.php?t=1958152, it's great. Use it with Nova launcher, and you will be amazed at the smoothness that our weak phone can deliver :highfive:.
I think you should use Nextgen rom because it had mount2sd script preconfigered and you wont have any problem
Sent from my HTC Explorer powered by Nextgen v1.5
Awesome Reply!!
redguardsoldier said:
Well, the answer to your question is kinda hard to understand, please read it carefully, as I spent time typing it here .
1/ Yes, card speed really matter, but it's not the class that matter. Class rating is for sequential write speed. For Android, what matters is random small-burst write speed. Read the first post of this thread http://forum.xda-developers.com/showthread.php?t=1005633. To successfully utilize your card, you must understand what you want to put on it.
An Android app normally have 3 parts: app (main apk), dalvik-cache, and data (your app's data like account, save game). app and dalvik will make use of sequential write/read speed, but data will benefit from random small-burst read/write speed.
Your internal memory is optimized for both type of read/write (that's why they're expensive like hell), while normally, SD cards are optimized for sequential read/write. Read again about the scripts you use, you will find that scripts that seem suitable for you have: app & dalvik on SD, data on internal. With data on internal, you will have a limit, because some apps use a lot of space for data.
Those scripts that make your internal memory become 1GB simply mount the SD-ext partition as internal memory, so everything is on SD cards, and the slow random write speed cripples your system.
Your best bet now is to try some configurable script like m2sd (I personally highly recommend it), have some patient setting it up, with app and dalvik on SD, leave data on internal, and you're good to go.
Use this link http://forum.xda-developers.com/showthread.php?t=1342387 to learn about m2sd if you're interested.
You should consider buying a fast card like Sandisk Ultra, they're not expensive. Remember to go with Sandisk (class 6 and up) when you're with Android. Some people also report that Samsung cards have great random write speed, and they're on sale more often than Sandisk (just avoid the Plus series). When you buy cards, always look for some benchmark about it's random 4k write speed.
And even with a fast card, I think you should still leave data on internal, data on SD put a heavy burden on your card, which can decrease it's lifespan soon.
I hope you read to this line, the post cost me more than 30 minutes . I just want to help :highfive:.
I attached the m2sd zip that I am using. And if you trust me, try MiniCM9 http://forum.xda-developers.com/showthread.php?t=1958152, it's great. Use it with Nova launcher, and you will be amazed at the smoothness that our weak phone can deliver :highfive:.
Click to expand...
Click to collapse
That is a great and dedicated reply ..... thanks redguardsoldier . Moreover I didn't understand the part where u say 4k write speed!! Don't these microSD cards write at speeds of 2 to 10 MB/s??? Or you are talking about random short read/write bursts!!!!
And as per your guidelines this what I have to do:
1. Buy a fast cast like Sandisk Ultra class 6 or up (I hope its microSD and not microSDHC kinda thing!!) or Samsung (except Plus series)
2. Use the m2sd script.
3. Use the following settings:
a. "data" on INTERNAL
b. "app" & "dalvik" on SD (and by SD you mean SD-EXT!!!)
4. And use miniCM9 though
I again appreciate your concern and grateful for taking out some of your precious time. Hope to listen from you again :good:
Regards
vikingmax said:
That is a great and dedicated reply ..... thanks redguardsoldier . Moreover I didn't understand the part where u say 4k write speed!! Don't these microSD cards write at speeds of 2 to 10 MB/s??? Or you are talking about random short read/write bursts!!!!
And as per your guidelines this what I have to do:
1. Buy a fast cast like Sandisk Ultra class 6 or up (I hope its microSD and not microSDHC kinda thing!!) or Samsung (except Plus series)
2. Use the m2sd script.
3. Use the following settings:
a. "data" on INTERNAL
b. "app" & "dalvik" on SD (and by SD you mean SD-EXT!!!)
4. And use miniCM9 though
I again appreciate your concern and grateful for taking out some of your precious time. Hope to listen from you again :good:
Regards
Click to expand...
Click to collapse
4k random write speed mean the speed that the card is capable of writing small blocks of 4kB each at random location . I talked about "random short read/write bursts" :good:.
About the microSD/SDHC/SDXC, that's just the type of size . It makes me confused at first :highfive:. Well, a long time ago, when cards are just 256MB, or 1GB each, they are microSD. microSD have the maximum size of 2GB. When the 4GB cards come out, they are called SDHC . And now, those hugh 32GB and 64GB cards are called SDXC.
redguardsoldier said:
4k random write speed mean the speed that the card is capable of writing small blocks of 4kB each at random location . I talked about "random short read/write bursts" :good:.
About the microSD/SDHC/SDXC, that's just the type of size . It makes me confused at first :highfive:. Well, a long time ago, when cards are just 256MB, or 1GB each, they are microSD. microSD have the maximum size of 2GB. When the 4GB cards come out, they are called SDHC . And now, those hugh 32GB and 64GB cards are called SDXC.
Click to expand...
Click to collapse
Thanks for your reply.. Helped me a lot too. What are your views on int2ext + or ungaze scripts?
Sent from my HTC Explorer A310e using xda premium

[Q] About swap space, this device and cyanogenmod

This may be a general question for all android devices or not but I was curious about adding swap space to this device. It has 1 gig of ram and many may consider that to be enough, and it might be. I have cyanogenmod 10.2 installed and tried to enable zram, 10% seems to be the best setting as anthing higher caused a game to pop up a notice saying something about low memory and defaulting to lower values. When I checked to see if zram was used however it turns out it was, about 25mb - 34mb after booting. The issue with zram is when multitasking with lecturenotes and moonreader, The tablet would reboot and my notebook that was open in lecturenotes would be missing notes I took or the settings would be greatly messed up, or both. This was with 10%.
I am thinking since it was used, it might be helpful to have an sd card for this reason, to aid in multitasking. This is important to me because I run several apps at once (I wish cyanogenmod had multi windows, and google wouldn't threaten over it). So the question is will there be a benifit to buying an sd card on ebay (class 10 of course) and using it as swap space. It seems this tablet might be on the cusp of the memory being enough. Also I am thinking this might help to future proof it a bit when updating to newer releases of gyanogenmod. The sd card I was thinking of is 4 gigs and may plan on having 1gb swap space (this tablet is for school and other work). The tablet has 32gb storage and that is more than enough for me (I am only using 3gb of space) so I wont need to add anymore storage.
I should also add that when multitasking without zram enabled, the tablet reboots less but still has done it, and so far nothing has been lost in my notebooks. I am thinking that the memory of 1gb is starting to reach its limit, with no apps running I am consuming about 600mbs of it.
vanquishedangel said:
This may be a general question for all android devices or not but I was curious about adding swap space to this device. It has 1 gig of ram and many may consider that to be enough, and it might be. I have cyanogenmod 10.2 installed and tried to enable zram, 10% seems to be the best setting as anthing higher caused a game to pop up a notice saying something about low memory and defaulting to lower values. When I checked to see if zram was used however it turns out it was, about 25mb - 34mb after booting. The issue with zram is when multitasking with lecturenotes and moonreader, The tablet would reboot and my notebook that was open in lecturenotes would be missing notes I took or the settings would be greatly messed up, or both. This was with 10%.
I am thinking since it was used, it might be helpful to have an sd card for this reason, to aid in multitasking. This is important to me because I run several apps at once (I wish cyanogenmod had multi windows, and google wouldn't threaten over it). So the question is will there be a benifit to buying an sd card on ebay (class 10 of course) and using it as swap space. It seems this tablet might be on the cusp of the memory being enough. Also I am thinking this might help to future proof it a bit when updating to newer releases of gyanogenmod. The sd card I was thinking of is 4 gigs and may plan on having 1gb swap space (this tablet is for school and other work). The tablet has 32gb storage and that is more than enough for me (I am only using 3gb of space) so I wont need to add anymore storage.
I should also add that when multitasking without zram enabled, the tablet reboots less but still has done it, and so far nothing has been lost in my notebooks. I am thinking that the memory of 1gb is starting to reach its limit, with no apps running I am consuming about 600mbs of it.
Click to expand...
Click to collapse
Well in my own personal testing i could not see any benefit while extracting 700mb archives under android with 4gb swap space on a 40mbs microsd card, while under full linux desktop with a same workload, swap differently helps keep the system smooth under heavy io load. The conclusion i drew was the android platform deals to memory management differently than the typical desktop os, due to slower emmc chips used as a boot disk for the majority of android devices using this slow, already bottlenecked memory as swap space doesn't make sense (not to mention the use of 2gb swap space on a limited 16gb storage etc), so android runs almost completely in ram, with stricter memory management and allocation allows android to run fine without swap space, although because of this, androids memory management makes little uses of available swap space
JoinTheRealms said:
Well in my own personal testing i could not see any benefit while extracting 700mb archives under android with 4gb swap space on a 40mbs microsd card, while under full linux desktop with a same workload, swap differently helps keep the system smooth under heavy io load.
Click to expand...
Click to collapse
I've been running my desktop without swap for the last 10 years, and as long as you have enough RAM for all your running programs, there will be no problem at all.
Extracting an archive is a mostly sequential operation (single read stream, single write stream), so it also doesn't benefit from caching, which could use the memory that is freed by swapping.
_that said:
I've been running my desktop without swap for the last 10 years, and as long as you have enough RAM for all your running programs, there will be no problem at all.
Extracting an archive is a mostly sequential operation (single read stream, single write stream), so it also doesn't benefit from caching, which could use the memory that is freed by swapping.
Click to expand...
Click to collapse
Ahh that makes sense. I wasnt sure if swap had an effect directly on the extraction, but seem keeped the rest system more stable/ smooth duing the process in the case of GNU/Linux, with swap off similar operations such as installing packages would more oftern lock the tablet up. Might be a placebo though
I also dont set swap on my Linux desktop, as it has plenty of ram but the benitfit of swap space is somewhat more noticable due to the lack of ram on the tf700.
JoinTheRealms said:
I also dont set swap on my Linux desktop, as it has plenty of ram but the benitfit of swap space is somewhat more noticable due to the lack of ram on the tf700.
Click to expand...
Click to collapse
I just want to share my user experiences on the swap space... It does seem to improve the tf700 with swap space due to the lack of RAM (1GB)..
Thanks for all the useful posts
Thanks for all the posts, I have my sd card on the way. I will post my experience when I get my sd card but I am sure it is safe to say there will be a benefit. I use linux to at home and have 8 gigs of ram on that computer, I lessen the swap after install to about 512mb because 8 gigs is more then enough. I leave some however just incase of any issues like ram going bad. On another computer in the house that has limited ram (1.5 gigs) I have enabled zram (384 mb) and added two old flash cards (1 gig each) to a pci raid card and those were converted to swap. I then altered the fstab to reflect the order of priority I wanted them used in. The reason is that when the swap is used from the hard drive, and the hard drive is being written to, can cause a slow down. So with the 2 flash cards at 1 gig each (the swap seen as 2 gigs) it seemed to speed it up. I just posted that because of the nix users and it seemed like a good plan to run it that way.
Ok, got the sd card
So I recieved the sd card today and applied the swap space to it using root swapper (max setting is 256mb, I figured i can find a way to increase it later if I need to). The defaut location in many of the swap applications will not work on this device however, the sd card mounts at /storage/sdcard1 in my case. So it has to be entered manually (might just be cyanogenmod). Also the device was picky when insalling the card, it would only say blank sd card or cannot read filesystem. I had to install the card in the dock, format it from cwm recovery, (vfat if I remember correct, ext2 and ntfs had issues, avoided ext3 and ext4 cause journaling will cause more wear and tear).
The sd card is a scandisk ultra sdhc uhs-1 8 gigs. From my research that is the fastest this tab can handle. I also use optimising programs like greenify (epic save everything app), pimp my rom (almost every tweak applied), and some pretty efficient tweaks in the settings as well. I also have HALO))) installed and working (epic multiwindow app that works with native programs and almost any rom).
The resuts:
I tested it many ways, I rebooted to see use (none was used because swap starts after boot), I opened apps normally (browsers and things), and it showed 9kb's was used. I then put it to the tests, I open four windows in halo, these were youtube, moonreader pro with a pdf ebook, lecturenotes (awsome note and handwriting app with tons of functions), and Supernote pro (not the best note app). Constantly switched between the apps and messed with settings with them open. The max of swap used was around 10mb(keeping in mind that when I switch windows the app(s) I leave get paused making it hard to tell actual usage because I had to swith the terminal and type "free". I then ran antutu bechmark and gpubench (my tab stills score pretty well) and got a little higher swap usage but not much.
As for the feel of it, it seemed to help when opening many windows in halo, this is the primary reason for my doing this. As for other more normal uses I really didnt see too much of a difference, I did test games however and they did seem a little better (could be placebo) but I am not really sure why they would except android cached other apps to free memory. Reopening apps seemed faster. Also because of apps like greenify my memory usage is decreased so I am sure typically swap would have seen more use.
The conclusion is that at this point I really didn't notice much of a boost for any normal use, but I will definately keep the swap space on due to the boost when using halo and not to mention that I will be updating to android 4.4 soon and it might need more memory. Swap at this point seems more like a pre emptive strike, but it does help with multitasking.
about swap
://androidforums.com/boost-mobile-warp-all-things-root/610449-ram-swapping-without-swapper2.html I actually followed a guide on android central and redid the swap file to 1 gig to swap instead of using a program, this worked better. (add http in front), when i disabled swap it was noticeable that there was a boost. then reenabled it this method.

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