Gp2x Sd Card Writing Speed

Discussion in 'General Talk' started by Cellsplitter, Oct 10, 2005.

  1. Cellsplitter

    Cellsplitter Member

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    ok, first of. HEEEEEYYY!! :lol: I'm back from the dead! Didn't think my login was still here ^^ haven't posted a thing since... :huh: forever! :p
    Some of you old veterans MAY remember me, or not ;P but who cares? Back to the topic!

    I'm looking forward for the GP2x :) and I was thinking of scooping around for a SD card right away (one obstacle out of the way, right?) and I noticed that alot of them have different writeing speeds on them. So naturally I wanna buy the fastest card! but, what is the maximum writeing speed for the GP2x? I don't wanna spend more money then necessary on it. Like for example: I buy a card with 10mbyte/sec writeing speed but the GP2x only suports like 5mbyte/sec or something.

    I expect an answer soon ;) see ya later peps

    edit: would of course allso know the reading speed :rolleyes:
     
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  2. bhxob

    bhxob Still Fresh

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    I think, for starters were looking at teh SD port running in mmc compatability mode. Which would be 20Mbit/sec (2.5MB/sec). Though it's possible that full SD speed will be achieved or implemented 100Mbit/sec (12.5MB/sec)

    See: http://en.wikipedia.org/wiki/Secure_Digital and look for the section labeled "Technical comparison" for data on various SD ports and standards.
     
  3. Cellsplitter

    Cellsplitter Member

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    so, it's possible for the GP2x to read/write the SD cards as fast as they are able to? If so I'll buy the fastest 1GB card I can afford :lol:
     
  4. bhxob

    bhxob Still Fresh

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    There are newer SD drivers in the 2.6.11 and greater kernels that allow for better SD and SDIO support, though some people have had it longer: http://www.handhelds.org/hypermail/mmc-dev...rent/0078.html. This, however, does not mean that the "better" support will be in the kernel initially provided by GPH.

    I'd still say 20Mbit for now.
     
  5. Aimless_E

    Aimless_E Member

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    Can't say for certain but Gbax.com is selling a High Speed 150X SD card on their site with the gp2x so it has to support 150X speed SD cards [circular, I know] :)
     
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  6. DijiTao

    DijiTao Member

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    The price difference between slow and fast cards isn't that great, so while initially there won't be support for high speed SD on the GP2X, it certainly seems like a worthwhile move to spend the extra couple bucks on the hope that it will be added later. It seems likely it will, but no promises can be made.
     
  7. Empyre

    Empyre *w00t*

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    Ah but cards greater than 1gb are all fast cards and it would be more expensive to buy 1x 2gb card than 2x 1gb cards unless the 1gb cards you buy are fast cards too IYSWIM. if it supports high speed sd then the 2gb card becomes more worthwhile

    well I know what I mean :p
     
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  8. Robster

    Robster Dodgy hardware mod maker

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    The speeds that you're talking about aren't really all that relevant.

    It could be that the SD card gets run in 1-bit MMC mode, which will mean 10Mb/sec or 900kB/sec. Or it could be run in 4-bit SD mode, which will mean 100Mb/sec or 9MB/sec.

    However, there's so much overhead involved, with the Flash erase and write delays, plus the software to do file and FAT handling, that these numbers won't be seen in reality.

    I think the only thing we can say for sure is that the MMSP2 chip has hardware support for MMC/SD, with DMA transfers and automatic CRC generation etc, so it will be a lot faster than the GP32's SMC interface :)
     
  9. Alpha2

    Alpha2 Heroic Autobot

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    I'm a little confused. Does this mean that MMC cards can be used instead of SD if you don't mind the lack of speed once new drivers are made availible? Granted the prices of MMCs arn't much better than SDs but if someone already had one it might save them from needing another atleast for the time being until there are apps the run outside of Linux or the drivers areready to support the full speed.
     
  10. iignotus

    iignotus The one and only

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    MMCs have always been usable in place of SD cards as far as I've witnessed.
     
  11. Empyre

    Empyre *w00t*

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    Other way around. MMC's are useable now, SD's are useable now at MMC speeds, Fast SD's will be useable at fast speeds with a driver upgrade

    Oh and transferring files to SD using a usb2 card reader, the difference n speed between a fast and slow card is very noticable. It will make a lot of difference when transferring movies across to play on the 2x.
     
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  12. judge0

    judge0 Member

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    IIRC the latest stable kernel for ARM processors is 2.6.4
    see www.arm.linux.org.uk

    On a brighter note 2.6.4 has excellent module support( ie user written modules for SDIO etc), provided we can upgrade kernel via JTAG or UBOOT
     
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  13. Alpha2

    Alpha2 Heroic Autobot

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    So really the only reason I'd be buying a SD card is if I intend on putting huge files on it untill new drivers become availible, right?

    I mean if I could save money by buying a MMC instead that's probably what I'd do.
     
  14. bhxob

    bhxob Still Fresh

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    The latest kernels from http://kernel.org appear to have support for the arm processors ( /arch/arm ) as well as support for the 920 series of procs ( /arch/arm/mm/proc-arm920.S ).

    This is from a stable kernel (2.6.13.4), though I'm not sure how or even if they are tested for their arm capabilities.

    If I'm not mistaken the link you posted is probably to someone who maintains an arm branch of their own, (like an AC branch.)
     
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  15. Empyre

    Empyre *w00t*

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    Right

    Though where I get em from, Slow SD cards are cheaper than MMC.

    1GB MMC = £39.99
    1GB SD = £36.50
    1GB Fast SD = £41.35
    2GB Fast SD = £89.99

    I think I'm gonna get 2 x 2GB Fast SD cards, one for software and one for movies
     
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  16. Alpha2

    Alpha2 Heroic Autobot

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    Okay cool, thanks for clarifying. If I did by the MMC I probably wouldn't be getting a 1gb anyway though for exactly that reason. Seems the higher the memory the more out of whack the price is in comparison.
     
  17. Ninjia^

    Ninjia^ Member

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    Hey, where are these prices from? I was just about to buy a 1Gb x133 speed SD card from Ebuyer for £50. Cheers
     
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  18. nubie

    nubie Recovering Jerk-A-Holic

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    MMC is not neccessarily slower.

    I have an A-Data "MMC 4.0" 1GB 100x card and it works very fast. I am able to watch the 720x500 whatever mp4s right off of it just fine. and it only takes a couple seconds to move 50 or so megabytes onto it.

    the carton says 15MB/s read, 8MB/s write. sounds fine by me, I have never seen a move encoded above 2MB/s anyway.

    I don't have my GP2X just yet, so that is reading off of my crap generic usb 2.0 12-in-1 adapter.

    Just so you know 100x hi speed MMC do exist.

    Mine cost $56 in the states(with shipping).

    The currency converter tells me that is about 36 GBP.
     
  19. sam fisher

    sam fisher Well-Known Member

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    I remember you!
     
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  20. Squidge

    Squidge Certified Guru

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    If you look at the SD specifications, it says that MMC is usually a 1-wire data transfer, running at speeds of upto 400Khz. SD is usually a 4-wire data transfer running at speeds of upto 25Mhz (but is backwards compatible, so can also be run as a 1-wire, 400Khz card).

    So, to get 15MB/sec, you must be using 4 parallel data lines, and thus the card must be a SD card, not a MMC card.
     
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