Accessing SD data on Megaflashrom SCC+ SD on 64kb MSX2+

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By wyrdwad

Paladin (846)

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05-01-2020, 13:31

Hey all,

Sorry if this is duplicated info from another topic or something, but I can't find the answers I need anywhere.

I received a 2-slot Megaflashrom SCC+ SD for Christmas from a very generous friend, but am having a lot of trouble getting it to work. I initially had trouble even getting my system to recognize the existence of the cartridge, but after using options F1, F2, and F3 from the recovery menu, then reinstalling nextor.rom /i from a floppy disk, that's no problem anymore. However, I have a base MSX2+ with 64 KB RAM, so I can't use Multimente as an operating system (which requires 128 KB RAM). So I figured the cartridge would boot into MSX-DOS on startup when I put an SD card in.

...Instead, however, it's recognizing the Megaflashrom, but booting into MSX BASIC. And when I type CALL SYSTEM or _SYSTEM, it just reloads MSX BASIC again. No matter what I do, I can't seem to access the many ROMs I copied onto my SD card to install them to the Megaflashrom.

Can anyone give me any advice on how to make this work? All the tutorials and such that I'm seeing online are for systems with 128 KB RAM, and I'm finding precious little information on how to work with this cartridge on a system with only 64 KB.

FYI, the system is a Panasonic FS-A1WX.

Thank you!

EDIT: I should note, I also tried inserting an MSX-DOS boot disk with OPFXSD.COM on it, then holding Esc on startup to have it ignore the Megaflashrom SCC+ SD and just boot from disk, figuring I could run OPFXSD that way to get around the issues I'm having booting from the SD. However, even when I hold Esc on startup, the system is still booting into MSX BASIC, ignoring the disk -- and even when I type CALL SYSTEM or _SYSTEM, it still just reloads MSX BASIC. I can't access the disk at all.

EDIT2: I should ALSO note that if I pop the SD card out (but leave the cartridge inserted) and hold Esc on startup, I can boot from the disk, then put the SD card back in. This way, I can run OPFXSD from floppy disk. However, when I do this, OPFXSD just exits with a "MegaFlashROM SCC+ not found" message. Seems I just can't win!

-Tom

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By Manuel

Ascended (16847)

Manuel's picture

05-01-2020, 13:59

For Nextor to work you als need 128kB of RAM. Apparently your MFR doesn't include the 512kB memory mapper?

By wyrdwad

Paladin (846)

wyrdwad's picture

05-01-2020, 14:07

It's cartridge only, so I don't have the box or manual to consult, but nothing on the cartridge indicates it does (and the memory message on startup still says 64 KB), so I guess not.

What options are available to me on a 64 KB machine? ARE there any? It feels like there should be, as there's no reason I shouldn't be able to at least run OPFXSD from a floppy disk to install games onto it from the inserted SD card. But so far, all my attempts to do so have been thwarted.

EDIT: Just tried combining the MFR with my Musical Memory Mapper cartridge. If I put the MFR in slot 1 and the MMM in slot 2, the system just boots without even recognizing the existence of the MFR. If I put the MMM in slot 1 and the MFR in slot 2, it recognizes the MFR, but freezes my system when attempting to boot from it. So that idea's out!

-Tom

By Wild_Penguin

Hero (606)

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05-01-2020, 14:30

wyrdwad: IIRC I've once booted from MFRSCC+SD on an MSX1 with 64kb memory into DOS1. I think that is the only option in your situation (unless you can get the Musical Memory Mapper working). You will not be able to use folders (there may be some hack to enable some folder functionality on DOS1 IIRC), but at least you can install flash games / MultiROM on it. EDIT: To be more precise, you need one (boot) partition on the µSD card and install MSXDOS1 on it, and you are good to go. I'm not sure, but MSX-DOS1 may have some difficulties with partitions. If you are lucky, you can put 4 partitions in there and have "4 folders". IIRC they need to be FAT12 and limited to 4MB - but you can not practically use that many files without folders in any case! You may want to check the FAT12/4MB limitation from somewhere, since that is from the top of my head...

Have you verified the Musical Memory Mapper works? IMO that setup should work... why it doesn't, seems like either a H/W fault somewhere or a bug in Nextor (i.e. DOS2/Firmware on the MFRSCC+SD). I'd presume this setup should not be that rare, so I think a bug is unlikely... EDIT: However being able to use MSX-DOS2 would make things a lot less complicated. You may want to use MSX-DOS1 interim until you get DOS2 working...

By wyrdwad

Paladin (846)

wyrdwad's picture

05-01-2020, 14:29

The problem is, I don't know HOW to get DOS1 running. I can't seem to run it from a floppy disk while the MFR is inserted -- or if I use workarounds as described in the OP to do so, OPFXSD doesn't recognize the MFR's existence. So while I'd love to boot into the thing in DOS1, I'll need someone to explain to me how to do that before I can try it! Wink

As for the MMM, it works just fine -- the issue is my MSX2+ model. There's a known issue with the FSA1-WX where the way it allocates memory is nonstandard (or rather, it's correct, while other systems allocate memory in a nonstandard way that a lot of programs expect). It's because of this that the MMM only sometimes allows me to play 128kb games on my system -- games like Pumpkin Adventure 3 and Akin play just fine, as they were programmed to recognize the proper memory mapping and thus see my MMM without any issue. Pumpkin Adventure 2, Ducktales, Morning Star, and a lot of other 128kb games, however, were programmed to expect the more nonstandard allocation that most systems use, so they freeze my system when I attempt to play them. (Apologies if my explanation sounds really technically inaccurate, but I don't fully comprehend the details of this; I just know that it's come up before, and the way it was explained to me is basically this.)

Presumably, the MFR is also not programmed to recognize the MMM properly on my system.

-Tom

By wyrdwad

Paladin (846)

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05-01-2020, 14:32

Quote:

EDIT: To be more precise, you need one (boot) partition on the µSD card and install MSXDOS1 on it, and you are good to go. I'm not sure, but MSX-DOS1 may have some difficulties with partitions. If you are lucky, you can put 4 partitions in there and have "4 folders". IIRC they need to be FAT12 and limited to 4MB - but you can not practically use that many files without folders in any case! You may want to check the FAT12/4MB limitation from somewhere, since that is from the top of my head...

I... have NO IDEA how to do any of this. I'm really, really not technically knowledgeable, so this all sounds like gibberish to me! Wink Sorry to ask, but can you walk me through the process? I'm in way over my head here.

-Tom

By Wild_Penguin

Hero (606)

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05-01-2020, 14:36

wyrdwad: Yeah, I didn't notice those details on your OP. However I've edited my post to reflect how I run MSX-DOS1 on the device (IIRC! I'ts been a while...).

MFR shuold not need to "recognize" MMM if I read the product page correctly, as it is an MSX standard RAM mapper. If there is a but, It more likely has to do with a but with slot mappings which the Nextor does not support; however IMO the next step should be to determine possible H/W faults. If you can boot from a floppy, have you tried running something to display current slot map? IIRC map.com or something similarly named utility exists ?

By wyrdwad

Paladin (846)

wyrdwad's picture

05-01-2020, 14:41

Yeah, it does have to do with slot mappings. IIRC, the mapping used by the Panasonic MSX2+ models reflects the official MSX standard, which differs from how most other hardware manufacturers implemented slot mappings for memory. As a result, unless a program was written to specifically recognize and use the proper MSX standard, it doesn't properly "see" the MMM, and the program behaves as if the extended memory isn't there (which usually means freezing the system).

It's a problem I run into a lot with this system, and I've been assured it's not a hardware fault, but a reflection of Panasonic adhering to standards that no one else bothered to.

The MMM definitely works, though, as I'm showing 1088 KB RAM on startup whenever it's inserted, without fail.

-Tom

By Manuel

Ascended (16847)

Manuel's picture

05-01-2020, 15:13

Boot to basic and then copy both msxdos1 files from floppy to drive a:, using the copy command in basic...

Still, I would expect Nextor to work with an external memory mapper.

By wyrdwad

Paladin (846)

wyrdwad's picture

05-01-2020, 15:43

Drive A *is* my floppy disk, though? Or does that change based on the state of the system during bootup?

How can I tell which drive letter is which?

And also, what good would copying the MSX-DOS files do? I have MSXDOS.SYS and COMMAND.COM on the microSD card in my MFR, but that doesn't seem to matter -- my system still boots to MSX BASIC, and refuses to boot into anything *but* MSX BASIC even when using CALL SYSTEM. I need a way to make it realize MSX-DOS is on the MFR and boot into it, but again, so far all my attempts at that have been thwarted...

-Tom

By st1mpy

Hero (537)

st1mpy's picture

05-01-2020, 16:04

I have a WX and MFR SD 512, when I keep pressing ESC and reset the machine it loads nextor.

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