Actually - in the Sharp advertisement, they "name drop" Microsoft
explicitly - so perhaps I misspoke in mentioning IBM's PC-DOS (but if we're
making disks, I'd just try to have both ready just in case). I've not
yet opened the external drive enclosure to investigate specific model/parts
(I'm very curious about the controller and how it differs from the standard
IBM ISA disk drive controller, but there is some difference since a 37-pin
drive that worked in my 5150 wouldn't work with this Sharp).
I'm generally clumsy with hardware (in a "oops, dropped that cup of screws
all onto the board while it was powered on" kind of way- maybe not that
bad, but enough to know to go slow and enjoy what I have for a bit first,
before I open it and screw it all up; my biggest regret was on a 1996
ThinkPad - it was running OS/2 just fine on a handsome solid state proxy
IDE, but I didn't like the color fade on the bezel of the CD-ROM, and just
"had" to going back in and address that - and that system has never booted
since). Point being, I'd like to try some disk first before tinkering
inside this drive enclosure. The host system is this: <
https://voidstar.blog/sharp-pc-5000 > which I hope to finally prepare a
broader video about it before the end of this year.
And - oh, depending on the controller, we might be able to adapt a 720K
drive onto it? I see, that'd be an interesting mod. But not yet - gotta
try as-is first. This Sharp is a tad confusing (or it was to me). I had
the impression that the DOS was built into the ROM - but no, it's actually
copied/placed onto each of the bubble memory cartridges, so it is always
"booting" to DOS like a "normal" system. Also in my notes - i may
have to
revise on if the BASIC is built-in or not. It's "built into" one of the
ROM cartridges you place into the bottom of the system. So it's not
technically a "boot to BASIC" system either (I'm not sure if that excused
them from Microsoft licensing in some way??). Or actually - I'll have to
unplug that cartridge and remind myself what all the system can do on its
own (as I recall, in doing so, it does "boot" into a self-running demo
mode).
I hope it's not too much of a lost cause - I think I do recall coming
across an article that mentioned that the system could be booted from the
external floppy. And if it could miraculously boot to something like DOS
3.2 - well, I can't think of any program of that era that would play nice
with an 8 row screen. But that's the goal here, to just see what
happens. In the worse case, this will mean I can make a backup of all the
content of these bubble memory cartridges content, just in case they start
to deteriorate in some way (that said - since it does have a "built in"
BASIC, I suppose technically I can do a BASIC that invokes the serial port
and I could export every file that way; thumbing through the manual it does
have some keywords that might accommodate that -- I'll save that as a last
resort).
And Thank You Travis, I'll be in contact!!
-Steve
On Tue, Sep 24, 2024 at 10:00 PM Fred Cisin via cctalk <
cctalk(a)classiccmp.org> wrote:
On Tue, 24 Sep 2024, Steve Lewis via cctalk wrote:
But does anyone here in the States happen to have
a stack of known-good
5.25 disks they don't want anymore?
Sorry, not right now
have a drive for an old system that currently
uses bubble memory
cartridges to boot to PC-DOS 2.0, and so we'd like to see if (using
these external drives) it could also boot to a (confirmed legit) image
of IBM PC-DOS (and/or very early Microsoft DOS). Or, do we still need
some kind of proprietary Sharp DOS image? (in which case, extra blank
disk would be good, as I think there are tools on these bubble memory
cartridges to initialize disks accordingly).
What kind of drive is it?
If it boots to PC-DOS 2.00, not MS-DOS 2.00, then it is not some kind of
proprietary Sharp DOS.
If Sharp, or whoever made your machine, ever did provide their own
customized MS-DOS, it was likely to be versions 1.25, 2.11, or 3.31
Many OEMs added 3.5 support in MS-DOS 2.00 amd 2.11. PC-DOS didn't
support 720K until PC-DOS 3.20, and 1.4M 2ith 3.30
(did anyone ever make a "USB-to-5.25"
drive? I have a couple 3.5
versions of those - maybe the power to motor the 5.25 is too much for
USB? :D ).
a few minor problems, in addition to power (easily solved with a external
brick)
There did once exist a few, but they are VERY rare.
There were also some with cooperative circuitry, that had an unmodified
3.5 drive in them that could be recabled to 5.25.
(still a few gotchas to deal with, such as "Disk changed" signal)
But, if you have a functioning 720K 3.5, you could put early 5.25 DOS on
it, even down to 1.00, and just use the first 40 tracks. In the days
before the 5170, the machine didn't really care,
--
Grumpy Ol' Fred cisin(a)xenosoft.com