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

Jules Richardson jules.richardson99 at
Wed Sep 9 11:56:31 CDT 2020

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.

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. 
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)

I'm guessing that the 'M' in MIO.SYS is "Mitsubishi" and the OS is tailored 
in some way to the machine.

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.

> Can you COPY files from the HDD to floppy?

Just filling up a few 360K disks with files at random so far, yes. But 
difficult to say if the file contents are correct.

>> Looking at the drive contents, incidentally, I didn't see anything that 
>> explains (or interacts with) that unusual video hardware - it basically 
>> just holds DOS and a bunch of documents written by the original owner. 
>> Maybe they got suckered into buying this fancy graphics hardware without 
>> having any actual need for it, and then of course EGA and VGA came along 
>> and rendered it obsolete anyway.
> It is probably completely CGA compatible, unless you invoke of of its other 
> modes.

Maybe. Assuming that the hard drive's directory contents are intact, and 
therefore there's nothing too unusual on the drive, I've perhaps got 
nothing to lose by reformatting - the only issue is that MIO.SYS, how it 
differs from Microsoft's, whether it's corrupt or not, and how - if it is 
intact - I can migrate it over post-install.

Of course maybe speed disk (if that is even the cause of my problems) has 
some kind of backup / undo aspect, but I doubt it.

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