AW: CGA card (Mitsubishi Electric) with 192K RAM?

Liam Proven lproven at
Wed Sep 9 12:19:35 CDT 2020

On Wed, 9 Sep 2020 at 18:56, Jules Richardson via cctalk
<cctalk at> wrote:
> On 9/8/20 6:04 PM, Fred Cisin via cctalk wrote:
> > Date and time of and any other DOS files will identify the
> > version number.

Only after DOS 5 or so, I fear.

> I've got 11/26/85 on
> > DIR /A  or
> > DIR /A:H
> > will let you see the hidden files (presumably IO.SYS and MSDOS.SYS; PC-DOS
> > had IBMBIO.COM and IBMDOS.COM instead)
> The /a switch isn't part of the dir command in whatever 3.3 version I have.

Yup. `ATTRIB *.*` might work in 3.3 though.

> However, I just wrote a DOS 6.22 boot disk and that shows three hidden
> files on the hard disk:
>    MSDOS.SYS (11/18/85)
>    MIO.SYS   (11/18/85)
>    SD.INI
> I'm guessing that the 'M' in MIO.SYS is "Mitsubishi" and the OS is tailored
> in some way to the machine.

Uhoh. Danger, Will Robinson.
> TYPEing "sd.ini" indicates that it's related to Norton Speed Disk - not a
> program I'm familiar with, but as that appears to be a defragmenter, it
> might hint at why my drive isn't bootable and seems to be having problems
> with various executables - I wonder if the directory structure "looks
> sane", but file contents have been completely mangled.

Oh dear, yes. If the machine is not totally vanilla but close enough
to boot vanilla DOS, then it's possible that  SPEEDISK could have run
but incorrectly and mangled stuff. Similarly running DOS defraggers on
a VFAT disk with LFNs would mangle them, in the Win95 era.

TBH, though, I'm surprised -- later versions of DOS (such as 6.22)
didn't run on DOS compatible machines, because they'd died out by
then. It was IBM compatible or nothing by the DOS 6 era, IIRC. So I'd
expect a later-era machine to be compatible enough that Norton etc.
would have no problem.

I ran things like PKARC and PKZIP successfully on DOS-compatibles in
the late '80s, because they only did legal file access and wrote plain
text to the screen. I wouldn't expect SPEEDISK to run on an early
Apricot or something.

Liam Proven – Profile:
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