27 Feb
2023
27 Feb
'23
2:50 p.m.
On Mon, Feb 27, 2023 at 12:06 AM Chuck Guzis via cctalk <
cctalk(a)classiccmp.org> wrote:
On 2/26/23 16:42, Chris Zach via cctalk wrote:
You should be using QD floppies, but those are rare. DD floppies from later
than
1985 though work just fine (discovered empirically while a poor college
student,
reconfirmed recently when I made all those Venix disks).
However, in a PC, to write these diskettes, you need a 1.2M drive. While
there is a couple of TEAC drives (55FR I think) that do 80-tracks at the
DD/QD
RPM and data rates, things get fussy putting them into PCs. And last time
I looked they were 5x the price of ye-olde-generic 1.2M floppy drive. As
long
as it's formatted at the right density/rpm rates, it's fine. And RX50.SYS,
if memory serves, does all that right.
Using 3.5" drives in double density mode will work, but there's a cascade
of software issues you'll have to deal with. I booted my DEC Rainbow with
these and some hacks from someone in the Jemez Mountains to do double
sided on MS-DOS (which reminds me, I have the hacks still, and they also
have a now lost-ish BIOS listing for 3.10b, so I should see if I can post
that for the few people still interested).I've never done it on a PRO
though.
I'm out in Colorado, or I'd happily give you one of my spares.
Warner
Oi.
So after finally getting things going I started copying the Pro/380 OS
files to a bunch of 1.2mb floppies. Great. However after a bit I started
getting errors, and found that the disks were getting gouges in the
tracks. Sure enough disassembly of my 1.2mb Teac showed that debris had
become embedded in the disk head and cleaning is not possible.
Terrific. Tossing the drive, this is not the first time I have had this
problem with these disks so I am dumpstering all of the old floppies and
just bought 40 new ones in sealed boxes.
However I'm now in need of a 1.2mb floppy drive. Anyone have a good
working spare that I can beg/borrow/buy in the MD area?
I thought the Pro 300 series used RX-50 drives; i.e. 400K 96 tpi DD
media. So even with your 5.25" HD drive, you should be using DD
("360K") floppies.