ED64 Plus... my impressions. Any Owners around here?

Discussion in 'Other Consoles & Oldies' started by Bonny, Feb 15, 2013.

  1. kuwanger

    kuwanger GBAtemp Advanced Maniac

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    Jul 26, 2006
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    The simplest guess explanation comes in three parts: it was probably easier, cheaper, and safer. It was easier because it meant simply patching games to have consistent save types or having the hardware support different save types natively then writing the load/save routine entirely in the boot loader in software. Having to do it in real time means either stealing CPU cycles from the CPU to do the writes or having the necessary hardware on the cart to do it behind the CPU's back. The former risks incompatibilities and the latter requires more expensive, complex hardware*. Both also might require a second save buffer (when RAM wasn't cheap) so you wouldn't get a mixed save--not really sure since if it's stealing CPU time it can just delay further progress in the game until the save is written. The last part is writing to SD, especially on a slow CPU, can take a while so the risk of corruption goes up a lot. It's really hard to do any sort of sanity checks*. To be really safe you'd want something like a capacitor in the cart to hold enough charge to fully do the write to SD even if power was suddenly lost*.

    The DS, unlikely most systems, doesn't directly map a ROM into the memory area. Hence the whole interface is predicated upon streaming content in from the cartridge and writing out content. Hence, it's conducive to having wait checks in allowing a flash cart to write out a save and say "everything saved fine". It also discourages constant writes to save memory. Basically, DS games behave more like CD-ROM games or cassette games so can get around most the hassle of direct rom/ram mapping. I presume these properties hold true for most modern systems, even those which have built-in storage.

    * The EZ Omega actually uses an FPGA to writes saves behind the CPUs back, but it still has issues because some games want to save near constantly. Hence some games are patched. It's also why it's such a headache for saves on the EZ Omega. You basically need something like multiple scratch files with hashes, you always have to worry about partial/mixed saves, and a power loss can cause massive filesystem corruption. And that's presuming you're not having issues like bad/questoinable contacts--which has seem to plague the EZ-Flash cards forever.
     
  2. MrCokeacola

    MrCokeacola GBAtemp Regular

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    Feb 26, 2018
    Canada
    Stupid question but are you trying to boot PAL roms or NTSC roms on the PAL console?
     
  3. bbsan2k

    bbsan2k Newbie

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    @saturnu That's a cool way to code it

    I forked altra to remove the protection, but currently I'm struggeling to build as setting up the toolchain on arch is a pain in the ....
    I'll update you guys if I can make it build!
     
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  4. bbsan2k

    bbsan2k Newbie

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    Jul 6, 2019
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    Alright - finally got it compiled! Unfortunately I don't have my ed64+ yet.
    Anyone willing to test?
     

    Attached Files:

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  5. MrCokeacola

    MrCokeacola GBAtemp Regular

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    Feb 26, 2018
    Canada
    I'll give it a test on my ED64+ when I get the chance.

    — Posts automatically merged - Please don't double post! —

    Screen of static follow by black screen. Didn't work for me.
     
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  6. bbsan2k

    bbsan2k Newbie

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    Jul 6, 2019
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    Damn OK then there might be something else that is breaking compatibility...

    EDIT:
    Could somebody please try, whether the original release of altra is booting up on the plus? If so, my build might just have some toolmaking issues
     
    Last edited by bbsan2k, Aug 8, 2019
  7. gtranche

    gtranche Newbie

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    Jan 21, 2017
    France
    Altra works on ED64+, for PAL rom you have to go in settings (right cross) and activate PAL for TV and sometime force NTSC or PAL mode, even if it's PAL rom sometime NTSC works.
    I have a problem with long filename .... if the filename is more than 64 caracs the rom won't load ...
     
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  8. bbsan2k

    bbsan2k Newbie

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    Hey,
    Did you try the version I linked above or the original version?
     
  9. gtranche

    gtranche Newbie

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    Jan 21, 2017
    France
    the original version.
    What is the protection you talk about ?
     
  10. bbsan2k

    bbsan2k Newbie

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    Jul 6, 2019
    Germany
    It’s the thing that saturnu mentioned some posts earlier. If you try to flash to SRAM, it will probably corrupt half the way through it, as there is some check for the existence of the OS64p file (which is only there on ed64+)
    I‘m gonna try compiling the latest release version again, as I just compiled the HEAD version from altra64 git
     
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