Which 4GB SD cards work/don't work with a FAT32 custom rom

**supersocialist** · 09/01/2006, 07:02 PM

I've seen mentions here and there of a particular brand of 4GB SD card failing to work with a custom rom, but I haven't been able to find a comprehensive list. I thought I'd start the thread, get some input, and hopefully come up with a new resource to go on the stickies list. As new replies are added, I will add the cards to this first post to keep a single comprehensive list.

Also, since this information is buried dep in other threads: the Palm FAT32 system operates much faster with larger allocation blocks. The default chunk size is 4k. FAT16 (FATFS.prc) operates well at that size, but FAT32.prc slows down noticibly. When formatting from a command line in Windows, use the following line:

format DRIVE: /FS:FAT32 /A:BLOCKSIZE

For a 4GB card, 32k is the largest chunk;
for a 2GB card, 16k is the maximum.
I hypothesize 1GB maxes at 8k, but I don't think we've seen that tested yet.

And now for the meat: cards marked with an asterisk(*) have been confirmed by multiple users.

Works:
*Transcend 4GB
*A-DATA 4GB
Patriot
RiData
OCZ

Does not work:
DANE-ELEC 4GB
PQi 4GB
Bluememo 4GB

**wagadesa#WN** · 09/02/2006, 12:32 AM

Personal Experience FAT32.prc w/ Treo 650 (Cingular)

Works:
Transcend 4GB

Doesn't work:
DANE-ELEC 4GB

**fkpalm** · 09/02/2006, 09:35 AM

transcend 4 gig is working for me.

Fred

**BNickO** · 09/04/2006, 10:01 AM

My A-DATA 4 Gig Card (150x) works great.

**supersocialist** · 09/04/2006, 12:42 PM

Originally Posted by BNickO

My A-DATA 4 Gig Card (150x) works great.

Man am I glad to hear that... I just ordered one!

**rinkeedink** · 09/05/2006, 08:57 AM

I returned a PQi card. My A-data also works great.

**BlueMagic** · 09/05/2006, 01:04 PM

My Patriot 4GB card works great

**TriangleRocks** · 09/05/2006, 01:47 PM

No problems with my RiData (150x) card!

**supersocialist** · 09/05/2006, 02:57 PM

Originally Posted by rinkeedink

I returned a PQi card. My A-data also works great.

Do you know if the PQi was a bad card, or bad brand? Did you try more than one?

**hopatz** · 09/06/2006, 12:15 PM

Bluememo 4gb not work with my treo 650 even using fat32.prc..

**swieder** · 09/07/2006, 04:41 PM

No problems with my A-data card (knock on plastic)

**Ddeath** · 09/10/2006, 10:13 AM

I have a problem with the Adata 4GB when using the camcorder, cannot write to it. Problem solved after reading the forums by filling up the card with more than 2GB of stuff and 32K cluster format.

**supersocialist** · 09/10/2006, 02:48 PM

Originally Posted by Ddeath

I have a problem with the Adata 4GB when using the camcorder, cannot write to it. Problem solved after reading the forums by filling up the card with more than 2GB of stuff and 32K cluster format.

It's my understanding this is a problem with FAT32, not ADATA specifically.

**+Kardboard+** · 09/10/2006, 04:00 PM

format E: /FS:FAT32 /A:32K doesn't work for me, it says that "specified cluster size is too big for FAT32". Eh????

**supersocialist** · 09/10/2006, 05:04 PM

Originally Posted by +Kardboard+

format E: /FS:FAT32 /A:32K doesn't work for me, it says that "specified cluster size is too big for FAT32". Eh????

Very interesting. I just tried this with a 128mb card and got the same error, but it definitely worked with my 4 gig card. I'll have to putz around with this when I've got more time.

**+Kardboard+** · 09/10/2006, 07:01 PM

Yeah, thanks. It's a Transcend 80x 1Gig card, by the way.

**supersocialist** · 09/10/2006, 07:38 PM

Originally Posted by +Kardboard+

Yeah, thanks. It's a Transcend 80x 1Gig card, by the way.

I'm starting to suspect it has to do with the ratio of allocation block size to total disk space. I reformatted my 4GB card the same way and it worked again. Unfortunately, I don't have a 1 or 2GB card to test, only 128mb, 512mb, and 4GB.

**+Kardboard+** · 09/10/2006, 08:20 PM

Uh...in plain Engrish? hahah

Is there a way to check cluster size? I formatted it on a "default" setting in Windows, but no idea what that is.

**supersocialist** · 09/11/2006, 12:23 AM

Originally Posted by +Kardboard+

Uh...in plain Engrish? hahah

Honestly, I'm not sure how plain this is. The first thing I wrote was an analogy using pie, but it made me hungry and concerned I might come off condescending. You'd be amazed how many people fly off the handle when they hear, "Well, it's like pie."

Anyway, file allocation blocks are the smallest size a file can be, and each takes some overhead for dealing with: the more chunks have to be moved, the longer it'll take, so one 32k chunk moves faster than four 8k chunks; additionally, the File Allocation Table from which FAT32 gets its name also has to account for every chunk, and sets aside space as a sort of table of contents. The more chunks you have, the more space you lose to the file allocation table.

(That's one reason your "120GB" hard drive might actually show up as "100GB," for example; the other is a marketting trick that has to do with the definition of "megabyte." 1/6th of your space would be a huge FAT (heh-heh) but I'm just making up numbers to serve as an example.)

However, there's a trade off with large chunks, because if you have 4k of data on 32k chunks, your 4k file actually occupies the full chunk, wasting 28k. If you have a 35k file, it takes two chunks, wasting 33k, etc. With larger drives a little waste is no big deal, but with smaller ones things get increasingly cramped. I wonder if there's an upper limit to chunk size as it relates to the total size ... but this is stuff I learned a long time ago and I'm rather fuzzy on some of the details.

Is there a way to check cluster size? I formatted it on a "default" setting in Windows, but no idea what that is.

Also from the command line, type CHKDSK DRIVE: (and add /F to do error-correction as well). It'll say "XXXX bytes in each allocation unit" near the bottom of the report.

This actually does reveal something useful, maybe: my 40GB drives have 4k allocation chunks, so 32k over 4GB is enormously wasteful. I'm not surprised that it doesn't even allow it for smaller disks.

**+Kardboard+** · 09/11/2006, 03:59 AM

That was WICKEDLY useful. Thanks!

So 8K is the biggest size of chunks my card can handle. haha will have to test speed later to see if that's the same as the "default" setting (which I can't find out right now, because it' sin 8K chunks.

)

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