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

[Fred Cisin]

On Tue, 8 Sep 2020, Jules Richardson via cctalk wrote:
> OK, it boots off a DOS 3.3 floppy if that floppy is inserted before it 
> attempts to boot from the hard disk. If I wait for it to do its "system file 
> not found" bit, followed by a subsequent prompt to insert boot media and 
> press a key, it attempts to access the floppy drive but then goes off into 
> la-la land. Odd.

How large is the drive?
If it is over 32MB, then try to find DOS 3.31 or newer.
MY preference is MS-DOS 6.22


> But anyway, taking the successful floppy boot route, I can certainly access 
> the hard disk in terms of bringing up directory listings and TYPEing files to 
> the display. So far, attempts to run anything from the drive just result in a 
> lock-up (keyboard immediately unresponsive, hard reset required). There 
> appear to be DOS utils on the drive, and command.com, but I've not checked 
> for hidden system files yet. fdisk shows the partition as active.

Date and time of Command.com and any other DOS files will identify the 
version number.

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)

Can you COPY files from the HDD to floppy?

Being able to access contents of files, but not RUN them seems odd.
IF the DOS on the floppy misunderstands the partition table, then root 
directory might look OK, but sub-directories might not be where it thinks 
they are, . . .


>> Got an IBM "Advanced Diagnostics" floppy to try?
> No, but I see that the minuszerodegrees site has an image, so I'll write that 
> out and see what happens.

NOT a big deal.  It's merely the only method directly from IBM for doing 
low level format.
In most cases, Speedstor is more useful for LLF.

> 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.

The ROM on the video card may be a BIOS extension, in which case access to 
extended modes may be handled internally in various programs.  For 
instance Windows 3.x, PC PAint, Pagemaker, and Xerox Ventura let you 
configure for a variety of video hardware.
Otherwise, check to see if CONFIG.SYS has DEVICE commands to load any 
device drivers, usually .SYS, although sometimes .COM

>> XT controllers tended to NOT be interchangeable, even between various OEMs 
>> of Xebec!
> Yes - something that people often seem to forget, too. I've run into that 
> quite often, where someone will hang onto an old drive because of the 
> contents, but they'll dump the controller that it was formatted against.

It always seemed counter-intuitive that makers of HDD hardware for XT 
didn't slavishly mimic IBM's XT HDD.  And especially counter-intuitive 
that different vendor Xebec controllers didn't always interchange.


--
Grumpy Ol' Fred     		cisin at xenosoft.com