MSX2 Disk not reading on pc / mac

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Par M2X_E1

Rookie (25)

Portrait de M2X_E1

03-03-2018, 14:49

Hi Folks,
I'm having difficulty in being able to read my double sided 720K msx formatted discs on PC or mac.
However it reads fine on the MSX itself. I used _FORMAT in the msx basic screen and also successfully saved an read a small file.
Any ideas why this won't work on the PC or MAC? (Both seem to support FAT12, which i assume msx discs are).

Thanks in advance,

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Par Grauw

Ascended (10583)

Portrait de Grauw

03-03-2018, 15:27

The disk drive may not support DD disks, only HD ones?

Par Manuel

Ascended (18794)

Portrait de Manuel

03-03-2018, 22:14

What kind of disk drive are you using?

Par zett

Hero (608)

Portrait de zett

03-03-2018, 23:47

Windows does not read fat12. not native. if you wanna read msx disks on a pc easy way is using linux. but 360k disks in a hd drive is somtimes read only. it says it can write but will do it ad 720k

Par Pencioner

Scribe (1524)

Portrait de Pencioner

04-03-2018, 01:28

I'm not sure if the issue is related but in old days when MSX disk formatted from BASIC with CALL FORMAT needs to be read under MS-DOS on IBM compatible computers, we were changing one byte in boot sector and after that you could use in on both computers. Don't remember any details on the byte position and values though...

Other issue is that modern drives often don't support 720K format at hardware level.

Par M2X_E1

Rookie (25)

Portrait de M2X_E1

04-03-2018, 08:55

The Drive I'm using on PC/MAC is BXXU0130 - IOmega Floppy drive which can read/write both 1.44MB and 720K discs.
The original drive in MSX I'm using supports 720K double sided.

It appears PC/MAC and MSX machines can create their 720K FAT12 discs but each have trouble reading the other despite having formatted in FAT12 and 720K, thinking there might be a subtle difference.

I'm curious re the boot sector. would this affect readability or just affect whether or not we can boot the machine from the disk?

Par gdx

Enlighted (5514)

Portrait de gdx

04-03-2018, 10:12

Maybe your drive driver is no longer supported by your systems. A generic driver controls the drive instead and it doesn't support 2DD. Try your drive on an older system with Virtual Box.

Par sd_snatcher

Prophet (3505)

Portrait de sd_snatcher

04-03-2018, 14:01


What versions of the PC/Mac operating systems are you using?

Par djh1697

Paragon (1637)

Portrait de djh1697

04-03-2018, 14:20

*IF* you are using a USB floppy drive you will probably have issues. I never got an MSX formatted floppy to work in a 3.5" USB disk drive.

Par Pencioner

Scribe (1524)

Portrait de Pencioner

05-03-2018, 00:39

M2X_E1 wrote:

I'm curious re the boot sector. would this affect readability or just affect whether or not we can boot the machine from the disk?

I don't remember much, i googled a little to maybe refresh some memories and i think it was the byte with offset $15 (0x15, &h15, etc) aka media descriptor byte, i think that MSX just used it differently (for clarity - computer was YIS805R/128) and the value which were at this byte if formatted by MSX was misunderstood by DOS 5.x making disk unreadable, so i'm not sure if that is really revelant for moder OS-es...

Par M2X_E1

Rookie (25)

Portrait de M2X_E1

06-03-2018, 22:34

I tried to find the disk which appeared to have formatted to 720K, turns out its probably a quirk of the disk manager software I'm using which seemingly writes as normal 2HD but sets the capacity to what it wants, in this case its a 730K capacity with an unusual 49.7MB available, which is clearly not possible. I used the iomega usb-floppy BXXU0130 (windows citizen floppy disk driver installed).

So to clarify to create a 720KB formatted disk, I need to run the FORMAT A: /N:9 /S: 80 in the command line on windows based systems, this doesn't work for my usb-drive but does work for an old PC with built in drive. I believe it will work for later versions of windows provided the drive is built in and the disk controller chip has the ability.

I assume that the usb-drive has no way of reading 720KB disks either, based on the fact its having trouble with msx formatted disk.

Will let you know of any new developments.

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