SD Cards?

[#1 GameMaster]

Are these some of the cards that are able to be used with the Pandora and what would be the best format for them if they are, because I've read that even though you can format them as Fat32 there is something about a slow down in seeking speed. But for $125 I'd definitely be buying some that is the lowest I've seen them yet and I can easily fill one up just with PSX games I think I have about 90 which still working on ripping them and so far am at 50 GB :blink: mainly because of my Final Fantasy collection.

 

[DaMummy]

if any of the psx emulators supports zipped or trimmed roms, it does wonders to save space, you wouldnt believe how much dummy data is in anything pre-bluray

 

[neko]

Are these some of the cards that are able to be used with the Pandora and what would be the best format for them if they are, because I've read that even though you can format them as Fat32 there is something about a slow down in seeking speed. But for $125 I'd definitely be buying some that is the lowest I've seen them yet and I can easily fill one up just with PSX games I think I have about 90 which still working on ripping them and so far am at 50 GB :blink: mainly because of my Final Fantasy collection.

Yes, I have one of those Sandisk 64GB cards, works fine.

 

[#1 GameMaster]

Yes, I have one of those Sandisk 64GB cards, works fine.

What format do you have it in? because I have a computer with windows and a laptop with linux and I think Fat32 is the only one that will run on both natively but I've heard that formating one that big in Fat32 could cause a slowdown. Then with some of the EXT formats I read that one of them does the journaling stuff which would kill it's life span, and it's not native to windows so do you know what would be the best format or if Fat32 really causes it to slow down that much. :huh:


Thanks for your reply, I'll definitely order mine since I believe that my Pandora will come either next week or the week after which would make a nice Birthday present.

 

[Eridger]

What format do you have it in? because I have a computer with windows and a laptop with linux and I think Fat32 is the only one that will run on both natively but I've heard that formating one that big in Fat32 could cause a slowdown. Then with some of the EXT formats I read that one of them does the journaling stuff which would kill it's life span, and it's not native to windows so do you know what would be the best format or if Fat32 really causes it to slow down that much. :huh:


Thanks for your reply, I'll definitely order mine since I believe that my Pandora will come either next week or the week after which would make a nice Birthday present.

Just use EXT3, if you have doubts about FAT. Yes, EXT3 uses journaling, but really, wear-leveling should totally take care of that, and there's a real sweet ext3 driver for Windows called EXT2-ifs (or similar) that makes it read almost like its native to Windows. 'Course there are programs for Windows that allow reading (not sure about writing) EXT4 partitions, but those aren't just drivers; those are full-blown programs, which totally destroys any seamlessness you might want.


If you wanted to go the EXT4 route you could just disable journaling. I think the Pandora's kernel supports that.


Edit I totally forgot about EXT2, which doesn't have journaling at all. That one would be okay, I think. I haven't messed with EXT2 at all, though. It's pretty old. Not as old as FAT, though.

 

[neko]

I have mine formatted ext3.


ext2 has no journal and therefore has the same problem as fat32 where you have to run fsck or chkdsk to clean up the mess left behind in case of an unclean shutdown or ejecting the card without unmounting it.

 

[Christoph.Krn]

What format do you have it in? because I have a computer with windows and a laptop with linux and I think Fat32 is the only one that will run on both natively but I've heard that formating one that big in Fat32 could cause a slowdown. Then with some of the EXT formats I read that one of them does the journaling stuff which would kill it's life span, and it's not native to windows so do you know what would be the best format or if Fat32 really causes it to slow down that much. :huh:

File systems: You might be interested in reading this: "SSD’s, Journaling, and noatime/relatime" by Theodore Ts'o. When using ext3 with "noatime", you most definitely won't encounter any excessive wear on your SD card. Whenever you attempt to use an SD card as a boot device, I recommend using NILFS, which is well suited for flash-based storage with integrated controller, whenever possible. It's a log-structured file system which will make all writes sequential, thereby eliminating the biggest problem of using SD cards as a boot medium, which would be the typical slowness of random writes.


Reliability/data loss prevention: While NILFS does have checksums on both data and metadata to assure integrity and has higher data safety than ext3 in case of a power shortage or system crash, it won't reduce the other big problem that you may encounter when using an SD card as a boot device, which is that the SD card may fail early and/or unexpectedly and/or just partly without you recognising due to bad wear-leveling, bad bad block management or similar management problems. Since currently it's VERY hard to compare the actual quality of any given SD cards, there are only very few which I can (based on my own, non-representative experience) really recommend to minimize this reliability problem.


Experimental - performance/lifespan increase: Also, since on most SSDs [sic] performance and lifespan will increase if parts of the user accessible flash are left /unpartitioned/ (not just free, but unpartitioned), this might also be the case for some SD card types. I have never tried or even benchmarked this with any SD card yet though, and I believe that most probably most SD card controllers aren't smart enough for this to work. However, it might work with some high quality SD cards, so I thought I'd share this information anyway. With SSDs [sic] you typically get the best (performance and lifespan increase)/(space usage) ratio when leaving about 20% of the user accessible flash unpartitioned (so for a 16GB SD card, that'd be about 3.2GB).

 

[- Theo -]

To be back on topic, just to let you know I received today my Transcend 32GB class 6 (the same as in the original post? Or maybe not, I bought it from Amazon UK) and it's working great. When copying large files (tried it with a couple of playstation images), I have 16MB/s write speed from my PC, which is great IMO.


Formatted at FAT32, didn't want to bother with EXT3.


Now I'm off to start playing FFVII again on my Panda

 

[second exodous]

I actually format as NTFS, it runs on everything and seems to get me better speeds than FA32 and not have the file size restrictions. It runs on Linux easily by installing the correct drivers and OSX even has them.


I don't care what anyone says, installing crap like file system drivers on Windows in a head ache, not nearly as easy as OSX or a Linux OS with a good package manager, so I'll try to keep Windows happy.


I say screw digital cameras and other devices that can't use NTFS, I guess I have to have cards just for them but my Pandora can still read their's.

 

[cosurgi]

I've found this post:


http://www.gp32x.de/board/index.php?/topic/54390-pandora-sdhc-speed-limit/


And I wodner now: buy 30 MB/sec card calss 10, or slower class 6. Has anyone checked with

dd if=/dev/card... of=/dev/null bs=4MiB

what's the speed limit?

 

[urjaman]

^ Dont remember exact parameters, but I have benched my Kingston's at 16.3MB/sec using dd, and I believe that it is the maximum until I hear somebody getting more


Anyways 48Mhz*4 bits == 24000000 bytes/s == 22.8881836 MiB / s is the maximum raw data rate (meaning take commands & crc's (etc) out of that).


Edit: IIRC the Kingstons are class 6 (or less, cant actually remember...)

 

[cosurgi]

I've bought a "SDHC 4GB class 10 233x Pretec" card, for 12 EUR (real cheap card), but it has nominal read speed 35 MB/sec. And benchmarks that I saw on internet apparently confirm this speed. On Pandora, 'dd if=/dev/mmcblk1p1 of=/dev/null bs=4MiB' gave 15.2 MB/sec. I will try to verify this card speed on my nikon D5000 digital camera to check if this card really has 35 MB/sec.

 

[Elanzer]

Since I'm 700-800 in the order list and expect to get a delivery confirmation soon, I decided it was time to buy some SD cards.


I found some good prices on some 32GB Class 10 Patriot SD cards for those of you in Canada:


$54.79 but limit of one per customer


$55.99 without limit


Things are looking much better than last time I checked, a few months ago it was about $80 for a class 4 32GB sdcard from a lesser brand. It's now cheaper to buy a 32gb card than it is to buy two 16gb cards.


Based off some benchmarks on the web, these 32GB Patriot cards should fully saturate the Pandora's SD bandwidth, with a sequential read and write of about 19mb/s and 17.5mb/s respectively.

 

[cwall]

This site has some micro SDHC cards results for different brands when used in embedded systems.


http://www.sakoman.com/OMAP/microsd-card-perfomance-test-results.html


The boot times for a fresh OS system doing its first startup configuration are interesting as the highest class cards do not always come out on top in real life software applications.


Carl

 

[Norfen]

So this question buried in a thread goes out to the OP team: what's the SD reader on the pandora specced at? (reads/writes/IOPS?)

 

[urjaman]

So this question buried in a thread goes out to the OP team: what's the SD reader on the pandora specced at? (reads/writes/IOPS?)

You really should be asking TI, not OP team. Anyways, the hard parameters set by the pandora design are:


- 4-bit mode


- 48 Mhz clock


From which you can easily math out a maximum raw data rate of about 22.88 MiB/s. Slowing down stuff:


- commands


- CRC's


- card's busy states (== the card)


Possibly (a little bit):


- OMAP interrupt latency / linux driver code (time from "DMA complete" to next "then read/write this" command)


- OMAP L4 bus bandwidth (if its being used by really lots of peripherals...)


... (cant think of more stuff, but there could be) ...


And yeah I just skimmed the entire OMAP3530 TRM chapter 22 "MMC/SD/SDIO Card Interface" for any performance figures. Screw that.

 

[Anihil8ion2199]

Found these for really cheap. Ordered two because of the price... Not sure of the quality though, has anyone used them before? If there not that good I don't want to use them on my Pandora, I'll use them for something else.

 

[cobrajs]

I just ordered two from Woot! too. I hope they work out, pretty awesome deal.

 

[second exodous]

I just ordered two from Woot! too. I hope they work out, pretty awesome deal.

I saw that also, kinda bums me out that I bought a third 32GB Transcend card. I don't think I'll use more than that and if I do I'll want to eventually upgrade to 64GB, or at least that will be the next card I buy a year or so from now.


Hope they work out for you, Woot.com rarely disappoint, I'm sure they tested a few of these cards before they sold them.

 

[DaMummy]

woot has nothing to do with quality of product, btw i came here just to post the woot deal myself, but i see couple people beat me to the punch, i dont see too many reviews on the cards, and the ones i do see are like 2/5, and its funny that every centon 16gb i find costs more than any 32gb i find....weird, so dont expect wonders with the cards, but the price is very tempting and hard to pass by...