Would it be possible to expand DSi's ram with an SD card?

Discussion in 'NDS - Flashcarts and Accessories' started by Wankare, Dec 19, 2009.

  1. Wankare

    Member Wankare GBAtemp Regular

    Oct 1, 2009
    Santo Domingo
    Dominican Republic
    i was just thinking , the dsi's ram is already big compared to the normal DS but its not enough for full flash support ( Like YouTube and stuff)
    if it is possible , Would you pay for a Flash Player Add-on DSiware that would use an external SD card as ram to work ?
    I WOULD PAY FOR IT !! please ninty! ~
  2. Crass

    Member Crass Rock me Dr. Zaius

    Nov 3, 2006
    United States
    No, this is the same reason why standard slot-1 cards cannot run GBA games. Semi-technical explaination why:

    A block device is a computer data storage device that supports reading and (optionally) writing data in fixed-size blocks, sectors, or clusters. These blocks are generally 512 bytes or a multiple thereof in size. The term is often used in contrast with a '''word-addressed device''' which supports reading and writing data a word at a time, where a "word" is a much smaller block, usually 1 to 8 bytes in size.

    * Block devices using rotating media
    o Floppy disk drives
    o Hard drives
    o Optical drives such as CD-ROM, DVD-ROM, UMD-ROM, HD-DVD, and Blu-ray Disc
    * Block devices using solid-state media
    o NAND flash memory cards, such as CompactFlash, SmartMedia, Memory Stick, and Secure Digital cards
    o NAND flash memory chips, such as the internal storage of some cameras, phones, and PDAs
    o Some NOR flash memory and mask ROM, especially those used on small handheld devices (such as cameras or the Nintendo DS handheld video game system) or devices that are also designed to use other block devices such as NAND flash memory
    * Word-addressed devices using solid-state media
    o Most mask ROM, such as NES, Super NES, N64, Game Boy, Game Boy Color, and Game Boy Advance Game Paks
    o NOR flash memory, such as PC BIOS chips and flash cards for the Game Boy Advance system
    o Nearly all RAM

    Advantages of block devices

    A block device generally requires fewer pins and can thus be placed in a smaller package than a word-addressed device. In addition, a block device interface to slower forms of memory, such as rotating media and NAND flash, is much easier to build than a word-addressed interface, and these slower forms of memory generally have a much larger capacity dollar-for-dollar than NOR flash. For example, a memory card for Game Boy Advance with 32 mebibytes of NOR flash costs about $60, but a CompactFlash memory card with 975 mebibytes of NAND flash costs $40, and a CD-RW disc that holds 700 mebibytes costs only $1.

    Drawbacks of block devices

    For some purposes, a block device based on a given solid-state memory is slower than a word-addressed device based on the same kind of memory because a read or write must start at the beginning of the block. Therefore, to read any part of the block, one must seek to the start of the block, read the whole block, and discard the other data if it will not be used. To write part of the block, one must seek to the start of the block, read the whole block into memory, change the data, seek to the start of the block again, and write the whole block back to the device. This is in addition to the typically longer seek times of storage technologies used on block devices. In addition, there must be at least one word-addressed nonvolatile memory in the system, even if only to copy the bootstrap code from a block device into RAM.

    Simulating ROM using a block device

    Because a CPU generally needs random access to individual bytes of program and data memory, a program stored on a block device needs to be copied to a word-addressed memory before it can be used. The N-Gage, GP32, and Nintendo DS systems, as well as all home computers and disc-based video game consoles, play games stored on block devices and have enough RAM to hold enough of a program in memory at once that loading rarely interrupts game play. Programs for those systems are designed to wait until the system finishes loading data before doing anything with the data, either by freezing game play briefly or by playing one part of a map while loading another.

    But on a system expecting a large word-addressed read-only memory, such as a GBA, a Game Boy Color handheld video game system, or any of several other video game systems, an adapter for a block device needs to contain enough NOR flash or RAM to hold a program. Copying from a block device to RAM is quicker than copying it to NOR flash, but NOR flash generally uses less power than RAM and retains the last program copied to it even when the power is turned off.

    Implementations in practice

    The first device that could copy programs from a block device to RAM and then run them on a GBA was the GBACD, an ATA interface designed by Michal Lysek and Tobias Persson, two students from Halmstad University in Sweden. A program running on a microcontroller could read games from a hard drive or CD and run them. It was designed as a proof of concept, not as an all-in-one piracy solution, but the foundation was laid for Supercard, especially as CompactFlash is electrically identical to ATA.

    The SuperCard and M3 adapters contain 32 MiB of RAM and a slot for a CF or SD card. They can play nearly all homebrew and pirated GBA games by copying them from the NAND memory to the faster memory and then handing control over to the GBA, though some do require patching so that savegames can be copied to the NAND memory. The EZ-Flash III and EFA II contain 32 MB of NOR flash memory used in a similar way, along with a much larger built-in NAND memory that can be rewritten but not swapped.

    The GBA Movie Player, on the other hand, was not designed to run pirated GBA games. It has only a 512 KiB NOR memory that stores its firmware, which consists of code and data for menus and movie playing and reads data from CF. This lets it run only multiboot programs (which fit entirely into RAM) on the GBA, although some multiboot programs such as the built-in audio and video players and special versions of PocketNES and Goomba use an ATA driver to read and write from the CF card, swapping data in and out of RAM as needed. However, this swapping can sometimes create game play delays, especially with larger games in emulators such as PocketNES, as the original games were not designed to wait for loading.

    Taken from: http://www.pineight.com/ds/block/
  3. Hatsu

    Banned Hatsu Someone's been killing, eh?

    Oct 19, 2009
    __________________ Warn: 50%
    Wow! Thanks for the info! [​IMG]

    EDIT: 444 posts.

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