Re: Supporting antique media

On Mon, 04 Jan 2010 23:57:14 -0700, D Yuniskis <> wrote:
I have to rescue a photoplot of a board I designed many
years ago off of an oddball machine.

Long story short: (ha!)

The file is on an old (i.e., small) hard drive in a
Compaq Portable 386.


And presumably an MFM hard drive.

The drive uses an oddball partition format -- so, even
if I wanted to cannabilize the machine to get the drive
out, it would be some effort to get a new machine to
recognize the partition format (I have no idea what it
is, off hand).

That assumes a modern BIOS can still cope with a 300MB
drive (I think that's what is in there -- that's part of
the problem -- note MB not GB!).

If it's an IDE drive (unlikely, but you can probably find specs on
the 'Web), you chould be able to attach it. If it's an MFM drive,
you'll need an MFM controller, and at least _some_ MFM drives were
controller-specific: if the controller went bad, a replacement
controller of the same type might not recognize it. As I recall,
this was a real problem for '086- and '286-era machines, less so for
the 386es.

I can't boot the machine because the CMOS battery failed
and the disk type parameter is no longer valid (nor are
any of the other BIOS settings).

Batteries (as another poster pointed out) can be replaced. 3V
(often 2x AA) was a common size, but ** CHECK ** before replacing
it. <grin!>

Of course, Compaq, in their infinite cleverness, opted to
put the "setup" utility on a *floppy* instead of in ROM.
Of course, I have not *kept* those floppies -- keeping their
*images*, instead.

But, having an image without a drive to write it is about
as useful as !

I understand -- I once had to use a Gen-you-wine IBM-Pee-Cee to
retrieve data from a Radio Shack TRS-80 II 8" floppy disk.

I found another simialr machine (Portable III) with a 5"
drive. And, with an assortment of antique software and
peripherals, I was able to get the image onto that drive.

The file? Or an image of the CP-386 hard drive?

But, keeping with their infinite wisdom, Compaq's utility
to *write* that image expects the drive to be 360K -- whereas
it is a 1.2M drive! (gee, guys, why don't you just *warn*
me that the media is "bigger than necessary" and let me write
the image anyway???)

Well, you probably have a serial port and a parallel port, and you
might even have a built-in modem. What difficulties would you have
with using one of these? After compressing the file, of course --
you might have to transfer it at 110 Baud. <grin!>

The fact that you have your image on a booting machine means all
sorts of possibilities exist. Heck, if you had to you could write
something in BASIC to flash the keyboard ScrollLock LED and read it
out through a phototransistor (but a serial port would be simpler
and require less wiring <grin!>).

And, I never (historically) have had any luck writing 360K
images onto 1.2M media (when I *had* those drives available)
so I question whether this is even a prudent approach...

My own attempts at writing to 1.2Mb floppies in a 360K drive have
failed more often than they have worked. You might think about
exploring your local thrift shops for a $10 ISA machine with
5.25" 360K floppy drives... it only has to run for a few hours.

I'm currently looking through my goodie box for a DOS tool that
will let me write an image on the Portable III that I can then
move to the Portable 386....

I think I just lost you on this step. If you have your file on the
P-III why move it back to the CP-386?

Anyway, the point of this is to solicit suggestions on how
to support antique media and obscure media *formats* on
modern hardware? I.e., even saving drives is no guarantee
that you can *write* them when the time comes... (when I
need to access 8" media, I have to do it via a serial port :< )

If your goal is being able to _read_ old data from a floppy or HD
image, then all you need is software to decode it. Bytes is bytes.
A sector-by-sector transfer of the HD you originally started with
onto a modern (as in "huge" <grin!>) hard drive and some software
would let you (eventually) retrieve your file from it.

In fact, I _suspect_ that you could mount an MFM HD-image under
Linux as a FAT-12 or FAT-16 filesystem and read off your file
directly. MFM vs. IDE has to do with the way physical sectors are
laid out and read/written; the partition and file system structures
are identical.

Good luck.

Frank McKenney
Hanlon's Razor: ÿNever attribute to malice that which can
be adequately explained by stupidity.ÿ
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all)