Samsung's Lag Fix

kennethpenn · Aug 23, 2010

http://xdaforums.com/showthread.php?t=762109

Can we replicate this on the Captivate? I've been playing around with my new Epic for a few days and it is AMAZINGLY fast. This is supposed to be the lag fix that Sammy employed on the Epic.

_Opiate_ · Aug 23, 2010

I knew it was just a matter of time until Samsung took action against the lag problem. I mean they wouldn't want their big, bad, and fast galaxy s line slowed to a screeching halt because of lag issues. I wouldn't be surprised if we see this in an update in the near future. With Samsungs track recored though they might end up waiting for Froyo to emplement it.

Sent from my SAMSUNG-SGH-I897 using XDA App

shep211 · Aug 23, 2010

We have a nand lag fix already right? Wouldn't this give the same results? I thought the ext 2 internal storage lag fix was faster the the nand fix.

http://xdaforums.com/showthread.php?t=737829&highlight=nand+lag+fix

TexUs · Aug 23, 2010

I'm no dev but I think this is the same thing that's already been implemented by the community (for that matter, Samsung probably got the fix from the community

)

l7777 · Aug 23, 2010

From what most have gathered, samsung didn't fix the lag, they used different hardware that is faster. That will do no good for captivate and vibrant users.

TexUs · Aug 23, 2010

l7777 said:
From what most have gathered, samsung didn't fix the lag, they used different hardware that is faster. That will do no good for captivate and vibrant users.

What the heck?
A) It uses the same hardware that matters anyway (granted LED, keyboard, etc is different).
B) Someone pulled the init.rc and proved what the OP is saying
C) You don't know what you're talking about

naxir · Aug 23, 2010

is there a good reference for the mapping of /dev/? or the whole file system in general? I went to see if busybox had a symlink for bash and much to my surprise there was no /bin. I'm new to android but a long time linux user and the differences are becoming readily apparent.

ranova · Aug 23, 2010

l7777 said:
From what most have gathered, samsung didn't fix the lag, they used different hardware that is faster. That will do no good for captivate and vibrant users.

I wouldn't go as far to say that. Everything is the same internally other than how the file system is setup, and in this case they are using the NAND (I believe).

From Boygeniusreport:
"We’re assuming the phone uses NAND Flash as the internal memory medium. On the Captivate if you navigate to Settings >SD Card and phones storage you see “External SD Card” and “Internal SD Card” listed. On the EPIC you see “External SD Card” and “Internal Phone storage.” We’ve reached out to Sprint for clarification and will update this article if they respond with a definitive answer."
Source: http://www.boygeniusreport.com/2010/08/18/your-epic-4g-questions-answered/

SiL3nTKiLL · Aug 23, 2010

same hardware, different software...just minor things different

Krynn! · Aug 23, 2010

The Epic is missing the 16gb internal SD card... the SD card that Samsung has split into 2GB for apps and 14GB for /sdcard for the rest of the US Galaxy S devices (no idea how the EU phones are set up). As a result, it has far less space for apps, but it more than makes up for it in speed.

About the only thing that I think Samsung can do to improve speed on the rest of the Galaxy S phones is to either work like hell to come up with a better driver for the internal SD card, or to accept a massive limitation in app space and build in the original lag fix.

I'm hoping it's just a driver issue... when copying a 1GB file to and from my /sdcard using the USB mass storage mode, I sometimes see 10+ megs per second, and sometimes see >1 meg per second. This is with my phone sitting idle, nothing else going on at all (except for OS Monitor, so I can see what's going on). That leads me to believe that it's either a driver problem or the internal SD card is the world's crappiest. Seeing as everything else on the phone is very nice hardware, and seeing how the GPS and compass drivers have issues as well, I'm kinda (and maybe foolishly) thinking that it's probably a driver issue. We'll see.

Unhelpful · Aug 23, 2010

It almost certainly is a driver issue. Formatting the internal SD with another filesystem provides a large boost in I/O performance. It's not as large as with the loopback hacks, which probably result in both subsystems buffering data, but it's enough to make using the device much more pleasant.

Sent from my SAMSUNG-SGH-I897 using XDA App

-=HOLLYW00D=- · Aug 23, 2010

not sure if this has been covered already, but it looks like the Galaxy S phones use NAND for internal storage and not a flash card. the following link:

http://www.sprintdroids.com/forum/s...-galaxy-s-torn-down-extensively-detailed.html

will link a Korean site that tears down a Galaxy S device. here's the direct link to the translated Korean page:

http://translate.google.com/transla....com/News_List_View.php?nModeC=4&nSeq=1742568

-=HOLLYW00D=- · Aug 23, 2010

andy2na said:
I wouldn't go as far to say that. Everything is the same internally other than how the file system is setup, and in this case they are using the NAND (I believe).

From Boygeniusreport:
"We’re assuming the phone uses NAND Flash as the internal memory medium. On the Captivate if you navigate to Settings >SD Card and phones storage you see “External SD Card” and “Internal SD Card” listed. On the EPIC you see “External SD Card” and “Internal Phone storage.” We’ve reached out to Sprint for clarification and will update this article if they respond with a definitive answer."
Source: http://www.boygeniusreport.com/2010/08/18/your-epic-4g-questions-answered/

on the Captivate, if you scroll down farther, past Internal and Externa SD Card, you will also see "Internal Phone Storage".

Unhelpful · Aug 23, 2010

not sure if this has been covered already, but it looks like the Galaxy S phones use NAND for internal storage and not a flash card. the following link:

http://www.sprintdroids.com/forum/s...-galaxy-s-torn-down-extensively-detailed.html

will link a Korean site that tears down a Galaxy S device. here's the direct link to the translated Korean page:

http://translate.google.com/transla....com/News_List_View.php?nModeC=4&nSeq=1742568

The Captivate has both, as you can see quite clearly in the shell by using the mount command. Most if the partitions are segments of the NAND, using /dev/block/stlXX devices, but /data is /dev/block/mmcblk0p2, the second partition of the internal SD card. All are Samsung's proprietary RFS filesystem, which appears to perform poorly on the SD.

Sent from my SAMSUNG-SGH-I897 using XDA App

-=HOLLYW00D=- · Aug 23, 2010

Unhelpful said:
The Captivate has both, as you can see quite clearly in the shell by using the mount command. Most if the partitions are segments of the NAND, using /dev/block/stlXX devices, but /data is /dev/block/mmcblk0p2, the second partition of the internal SD card. All are Samsung's proprietary RFS filesystem, which appears to perform poorly on the SD.

Sent from my SAMSUNG-SGH-I897 using XDA App

pardon my ignorance, as i truly am ignorant in the subject, but how are logical names proof of physical hardware? could Samsung not have partitioned a NAND chip with different mount points and call them whatever they want? from the tear down pics, it seems that there would be no room for an internal SD card on the PCB. also, from reading around, it seems that all Galaxy S phones are pretty much the same hardware-wise, is this not true for the Captivate version?

again, i don't mean to come off antagonistic. i'm just searching for knowledge.

alphadog00 · Aug 23, 2010

I just wish everyone would quit calling the system memory an "Internal SD card". There is no such thing. Samsung gave it this stupid name so the simpleton's of the world would realize it was data storage.

SD - Secure Digital is a form factor design. The phone has different kinds of flash memory and no one has yet to determine if the 14GB "internal SD" is a seperate chip from the total 16GB of internal storage.

Comparing this "Internal SD" to a real SD card is just dumb. An SD card is removable, of a certain physical size, has a write protection, and supports built in DRM - part of what Secure Digital means.

I am speculating too, but until someone can pinpoint the chips used on the captivate, we don't really know what this internal SD is made of.

alphadog00 · Aug 23, 2010

-=HOLLYW00D=- said:
pardon my ignorance, as i truly am ignorant in the subject, but how are logical names proof of physical hardware? could Samsung not have partitioned a NAND chip with different mount points and call them whatever they want? from the tear down pics, it seems that there would be no room for an internal SD card on the PCB. also, from reading around, it seems that all Galaxy S phones are pretty much the same hardware-wise, is this not true for the Captivate version?

again, i don't mean to come off antagonistic. i'm just searching for knowledge.

I agree - SD is just NAND with DRM and some other features. I think Samsung just calls it this to separate internal OS/Application storage from user addressable storage. I would be there is one 16GB NAND chip as I have never heard of a 14GB chip. I bet they just partitioned the 16GB chip in different ways, but for some reason gave the 14GB chunk a slower FS partition by mistake.

Krynn! · Aug 23, 2010

Unhelpful said:
It almost certainly is a driver issue. Formatting the internal SD with another filesystem provides a large boost in I/O performance. It's not as large as with the loopback hacks, which probably result in both subsystems buffering data, but it's enough to make using the device much more pleasant.

Ah, good to know then. Thanks!

Unhelpful · Aug 23, 2010

It is not only a logical name. While there may not be a removable card in a slot, the name suggests, and information in sysfs agrees, that the "internal SD" is accessed via an sd/mmc host controller. This means that many details about the flash are being hidden from the OS - it doesn't know what the erase block size of the flash is, it only sees a device with a certain number of blocks and a partition table at the beginning. Block remapping and wear levelling are hidden, which is why we can't use any of the linux filesystems for MTD devices. And for some reason, I'm not sure why, RFS performs much worse on an mmc device, or at least on this one, than it does on the OneNAND partitions. That it should matter seems a bit odd, as they are both block devices, but perhaps the OneNAND driver exposes some other information or interfaces via ioctl calls that are not present on the mmc device.

It is certainly possible for a filesystem to perform better on the internal SD than RFS does - this is easily demonstrated by formatting it with ext4 or nilfs2, and is also suggested by the improvement in lag that some seem to see with the leaked firmwares. In the future we may not care about alternate filesystems, because we get an rfs module that performs better on the internal sd.

-=HOLLYW00D=- · Aug 23, 2010

Unhelpful said:
It is not only a logical name. While there may not be a removable card in a slot, the name suggests, and information in sysfs agrees, that the "internal SD" is accessed via an sd/mmc host controller.

sounds reasonable, thanks. but getting down to it, is it not at all possible that the internal "memory" is a physical NAND chip, albeit partitioned and interpreted logically however Samsung saw fit?

this may seem like a pointless debate, but perhaps if the community knew it was NAND for a fact, they could rewrite this or that to make things faster/better/etc..

here's a link that revers to the internal memory as NAND. not the source i'm looking for, but it's something:

http://www.66mobile.com/phones/samsung/samsung-galaxys.html

here's another spec sheet referencing NAND:

http://www.dropshippers.co.za/W32574411-Samsung-I9000/Documentation.html

here's an official Samsung site referencing NAND:

http://www.samsung.com/uk/consumer/...dex.idx?pagetype=prd_detail&tab=specification

Samsung's Lag Fix

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