Database Info

Memhack

There are various mentions of a "memhack" to apply to the Milestone which apparently frees up some RAM. It also apparently can cause problems when flashing a different SBF.
Could someone help me out here by clarifying exactly what the memhack does and what are the circumstances under which it can cause problems?

Looks like this never got an answer, but now I'm seeing that some of the custom nandroid backups here make reference to using memhack. Could someone help me clarify this? I find a lot of Google hits but no explanations except in German... and it doesn't translate very well.

memhack does not free RAM but storage space. It simply moves the cache partition so you get more space for installing apps. As long as you wipe everything when restoring different nandroid backups, I don't think you can really have any issues. Also I don't really think it can affect your ability to flash SBF's. Maybe OTA updates could only be affected as cache gets moved where OTA upgrades are supposed to be downloaded and unpacked.

cmstlist said:
Looks like this never got an answer, but now I'm seeing that some of the custom nandroid backups here make reference to using memhack. Could someone help me clarify this? I find a lot of Google hits but no explanations except in German... and it doesn't translate very well.
Click to expand...
Click to collapse
If you open the script, if I recall correctly, it tries to move the dalvik-cache from the system partition to the cache partition, thus saving you space on the system partition.

i believe the latest version of apps2sd does this automatically ? i've got apps, apps-private and dalvik-cache on my sd card now...

somethingdope said:
i believe the latest version of apps2sd does this automatically ? i've got apps, apps-private and dalvik-cache on my sd card now...
Click to expand...
Click to collapse
Yeah, if you have apps2sd you don't need to apply memhack. In fact, it might mess up your device since the symbolic links for dalvik-cache should be pointing to the SD card, not the cache partition.

Thanks for clarifying. I'm starting to run low on app space on my Milestone but I'm not keen to use the apps2sd hack as I've heard it can cause all sorts of trouble. Not impressed that official Froyo is so far away.

cmstlist said:
Thanks for clarifying. I'm starting to run low on app space on my Milestone but I'm not keen to use the apps2sd hack as I've heard it can cause all sorts of trouble. Not impressed that official Froyo is so far away.
Click to expand...
Click to collapse
It's really not that hard once you understand how all of these things work. "Memhack" is too 'scary' a name for a simple thing.

dsixda said:
Yeah, if you have apps2sd you don't need to apply memhack. In fact, it might mess up your device since the symbolic links for dalvik-cache should be pointing to the SD card, not the cache partition.
Click to expand...
Click to collapse
this is not correct.. its actually a worst case scenario, and /dalvik-cache should only be on sdcard, when you're a apps hungry person that cannot work with 100MB free for the purpose..
current disadvantages on milestone for using dalvik on sdcard;
- unstable and slow ext2 kernel module..
- lacks direct io support
- slows phone if sdcard is class2 only.
- no support for wipe of /dalvik-cache folders with any current recovery.
- not a solution if no sdcard is present or paritioned correctly.
(suddenly /data is full?)
Advantage over sdcard pointers for dalvik are;
- faster seek times
- faster loading
- easier cleanup if required when switching roms
- still works even without sdcard inserted.
but if people dont care or know the consequences of their changes, they just accept.

Dexter_nlb said:
this is not correct.. its actually a worst case scenario, and /dalvik-cache should only be on sdcard, when you're a apps hungry person that cannot work with 100MB free for the purpose..
current disadvantages on milestone for using dalvik on sdcard;
- unstable and slow ext2 kernel module..
- lacks direct io support
- slows phone if sdcard is class2 only.
- no support for wipe of /dalvik-cache folders with any current recovery.
- not a solution if no sdcard is present or paritioned correctly.
(suddenly /data is full?)
Advantage over sdcard pointers for dalvik are;
- faster seek times
- faster loading
- easier cleanup if required when switching roms
- still works even without sdcard inserted.
but if people dont care or know the consequences of their changes, they just accept.
Click to expand...
Click to collapse
I actually didn't experience any performance gain or loss when moving my dalvik cache to my Class 6 card. I also have no need to remove my SD card. Of course most people should be aware that moving anything to SD requires at least a Class 6 (usually) if you want any kind of performance.

dsixda said:
I actually didn't experience any performance gain or loss when moving my dalvik cache to my Class 6 card. I also have no need to remove my SD card. Of course most people should be aware that moving anything to SD requires at least a Class 6 (usually) if you want any kind of performance.
Click to expand...
Click to collapse
Classes don't mean much for SD cards. They do to an extent, but in the end you really need to rely on benchmarks.
Class simply means minimum speed. A Class 6 card could run as slow as 6 MB/sec or go as fast as 20 MB/sec. Not sure.
I have a Sandisk Class 4 8gb microSDHC card. I saw the 16gb benched at 15MB/sec or so. I can hit 18-19MB/sec on mine.
This is considerably faster than the 16gb Class 2 that my Milestone shipped with. It's also considerably faster than the 16gb Class 6 Transcend I wanted to get. But remember my Class 4 promises 4 MB/sec transfers. These speed tests I've done are pretty darn fast.
Another example is my Class 6 Transcend 16gb SDHC (not micro) for my Canon Rebel camera. I benched it around 8.9 MB/sec. That's within Class 6 limits, but presumably my Class 4 8gb microSDHC Sandisk mounted on an adapter should do even better fine if I was able to bench it at 18 MB/sec on my computer....
So it's hard to say. If a Class 2 is really Class 2 at its minimum 2mb/sec, that's a pretty darn slow card.

Ok well I was getting close to that 20 MB "low memory" threshold so I memhacked using GOT OpenRecovery 1.04a. Nandroid backup first of course. Available space has skyrocketed to 91 MB! Sweet.

[Q] Intall apps on to phone memory or move to SD with a Kingston Class 10?

I don't have space issues so far on my internal memery (only 1/2 used with no apps on the SD card).
But curious to find out if its acutally better to move the apps to the SD card since its a Class 10? Or will moving to SD slow down stuff in general regardless?
Anyone with any ideas?
Loving the Class 10 for quick copying of music and especially movies from my PC though!

Good question. I might be interested in your answers on it as I moved a few softwares on my Kingston SD card (class 10) and haven't seen much difference in terms of speed

Anyone with any info? People familiar with Android I/O stuff?

usually i will move games to SD Card but important apps related to system and network like keyboard, battery, SMS apps on the internal memory.
Anyway, I just realised today that after I moved my Angry Birds to SD Card, the shortcut icon on the home screen cannot be loaded. Anyone has this issue as well?

giggss said:
usually i will move games to SD Card but important apps related to system and network like keyboard, battery, SMS apps on the internal memory.
Anyway, I just realised today that after I moved my Angry Birds to SD Card, the shortcut icon on the home screen cannot be loaded. Anyone has this issue as well?
Click to expand...
Click to collapse
change scene to something else, than back to normal. usual sense ui error with icons

giggss said:
usually i will move games to SD Card but important apps related to system and network like keyboard, battery, SMS apps on the internal memory.
Anyway, I just realised today that after I moved my Angry Birds to SD Card, the shortcut icon on the home screen cannot be loaded. Anyone has this issue as well?
Click to expand...
Click to collapse
thats the key, all important apps should stay internal, especially if your SD funks up.
plus its MUCH quicker from internal, even if its a class 10..
im using an kingston 8gb C10 as a secondary, and media and thumbnails are blazing fast...no speed tests yet, didnt really care that much, but ill post if i get the chance

r3v0Lut10n said:
change scene to something else, than back to normal. usual sense ui error with icons
Click to expand...
Click to collapse
Thanks! But aren't them going to fix this irritating sense ? Sigh, I still prefer non-sense..

How can I see how much memory is allocated to move programs to on SD card?
I like to have my programs on SD card (I think it can only influence the loading time when a program is started, after that it wil remain in main memory). But after some programs I got the message 'no more memory available' altough there is stil 2,5GB free on the SD card.
Does it mean that android allocates a part, if so how much and is it expandable?
thx

Media/sd card scanning after reboot – cannot disturb?

Ok so I moved a lot of apps to my sd card but have noticed if I try to do ANYTHING – even make a phone call after my phone boots but before the media scanner finishes – some of my apps aren’t available till I reboot again and let it run and complete...
In fact, I think it even doesn’t complete correctly if I open my home screen (but don’t open any programs) while the media scanner is running…
I get the generic dark/black sd icon and when I click on it says not installed…
If I reboot my phone and let the media scanner/sd scanner thing run before I do ANYTHING – everything is perfect.
Is this normal?
thanks!

that is normal
If you have used an app to push your apps to SD you have essentially made it worse (depending on size of ext SD and content)
Class/speed of SD card will make a difference to
Sent from my SAMSUNG-SGH-I727 using XDA App

00mred00 said:
that is normal
If you have used an app to push your apps to SD you have essentially made it worse (depending on size of ext SD and content)
Class/speed of SD card will make a difference to
Sent from my SAMSUNG-SGH-I727 using XDA App
Click to expand...
Click to collapse
So if I purchased a 32 gb Class 10 card would things improve or degrade it is pretty bad now with jst a 4 gb. sd card. I use nitrality and that seems to help a lot but man sd card scanning is just horrendous on this phone and my Infuse as well. And I have not moved any apps to sd.

Class 10 should be better
Blackberrynomore said:
So if I purchased a 32 gb Class 10 card would things improve or degrade it is pretty bad now with jst a 4 gb. sd card. I use nitrality and that seems to help a lot but man sd card scanning is just horrendous on this phone and my Infuse as well. And I have not moved any apps to sd.
Click to expand...
Click to collapse
Sent from my SGH-I727 using XDA App

[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

Samsung 64GB SD Card - SO SLOW

So I ordered a Samsung 64GB Class 10 micro SD card, and it seems VERY slow.
While I gone so much mind the slowness, as I dont play a lot of games and would use it more for pictures and music I was wondering if I could get a few questions answered before I send it back or just give it to someone else.
1: Does the S4 have problems with 64GB cards?
- I am running Sacs KitKat V2
2: should I format with a format (NSFT/exFat) and is it better done on a Mac or PC?
3: what should the Unit Size be?
4: I just copied my old sd card on to this one, and some of the big games I do have stopped showing up. but when I put my old card back in, they are there again.
Why would this happen?
Thanks for the help everyone!

You have to format the card using the phone itself. Go into settings then storage and the option should be there. Try that, then re-copy your stuff to the card. If you still have problem then it is probably a dud card.
Sent from my SAMSUNG-SGH-I717 using xda app-developers app

You shouldn't re-format it at all from stock, but if you do you should try the official SD Formatter: https://www.sdcard.org/downloads/formatter_4/
I have a samsung 64GB microsd in my S4 and it's ridiculously fast according to SD Tools (http://i.imgur.com/EXUVIP7.png), probably a caching causing that; but anyways, it's great in normal use copying roms over/etc.

Oishikatta said:
...probably a caching causing that
Click to expand...
Click to collapse
LOL, you don't say! Divide those numbers by 10 and you have a more realistic speed indication :good:

Pfeffernuss said:
LOL, you don't say! Divide those numbers by 10 and you have a more realistic speed indication :good:
Click to expand...
Click to collapse
No, samsung does claim the card gets 70MB/s read and 20MB/s write - and the reviews on amazon match that even for the lower priced card:
http://www.amazon.com/Samsung-64GB-PLUS-Micro-Adapter/dp/B00I4ZMNY4/
Obviously the SD Tools benchmark isn't testing the actual card performance, but what matters is that in actual use the samsung cards are great.
Windows/crystaldiskmark can also easily be used to do a real test.
Here's in a usb 2.0 card reader:
Sequential Read : 23.455 MB/s
Sequential Write : 17.352 MB/s
Random Read 512KB : 22.898 MB/s
Random Write 512KB : 16.407 MB/s
Test : 100 MB [D: 32.1% (18.8/58.5 GB)] (x5)
Date : 2014/03/26 11:16:15
OS : Windows 8.1 [6.3 Build 9600] (x64)
If @chaos67731 isn't getting at minimum 10-20MB/s after formatting the card then there's probably something wrong with it.

chaos67731 said:
1: Does the S4 have problems with 64GB cards?
- I am running Sacs KitKat V2
2: should I format with a format (NSFT/exFat) and is it better done on a Mac or PC?
3: what should the Unit Size be?
4: I just copied my old sd card on to this one, and some of the big games I do have stopped showing up. but when I put my old card back in, they are there again.
Click to expand...
Click to collapse
1: A good amount of users (including me) had problems with their SD cards on S4s. The problems are between:
occasional unmount/remount (the system does this for no apparent reason). S4 cant read cards after a sudden unmount, and cards usually get killed. most of the cards reported are 16,32 and 64 GB micro SD kingstone. SandDisk has problems too but I'm not sure about Samsung's.
2: Just use the official SD formatter mentioned by @Oishikatta above.
3: if you used the official SD formatter you wont have to deal with Unit Size. (personally, I dont know what's that)
4: Do you use a card reader when you copy your memory card? or do you just connect the phone using a cable? try using a card reader when copying your SDs. Some hidden files may not appear if you used the cable.
I hope I helped and excuse my English, its not my native language.

Well if you have a SanDisk they want you to format exfat. http://kb.sandisk.com/app/answers/d...sion/L3RpbWUvMTM5NTg5ODI5OS9zaWQvRDdTTFVmUWw=

Oishikatta said:
No, samsung does claim the card gets 70MB/s read and 20MB/s write.
Click to expand...
Click to collapse
Sure, on a PC with an appropiate very fast SD-card reader. Using a phone you won't get those advertized speeds.
This is the result with a more proper SD-benchmarking app (although internal and external SD are shown in reverse):
These values will be more realistic. SD-Tools results (cached) don't mean jack, unfortunately.