Early 3.5" Floppy Drives
chenmel at earthlink.net
Mon Dec 12 19:59:34 CST 2005
On Mon, 12 Dec 2005 12:50:12 -0800 (PST)
Fred Cisin <cisin at xenosoft.com> wrote:
> On Mon, 12 Dec 2005, Curt @ Atari Museum wrote:
> > Interesting... 600rpm? Wow!
> Yes, but with a 500K data transfer rate, giving the same "720K"
> for DS.
> > Didn't Seagate/Shugart dabble in 3.5 disk drives early on
> > around 83 or 84'ish???
> Shugart Associates.
> Alan Shugart started Shugart Associates, and produced floppy
> drives. Then he sold the company to Xerox?
> Then he started a new company, "Shugart Technology" and produced
> hard drives. Xerox's lawyers pointed out that they had bought
> the name "Shugart", so he renamed Shugart Technologies to
> "Seagate". Moral: don't name your company after yourself, or you
> could lose ownership of your name when you sell.
> The earliest Shugart 3.5" diskettes did not have a shutter.
> Later diskettes had a shutter that required manual opening, but
> had a spring to slam it shut when you "pinched" the corner.
> They had an arrow pointing to the correct "pinch" location.
> Some relatively modern "fully automatic shutter" disks still
> have that arrow! 'course most folk prob'ly think that it's to
> tell them which end of the disk to put into the drive.
> > >>adoption of them into its Mac's in 84' then Atari and Amiga
> > >following in >85/86 with their systems using 3.5's and
> > >eventually IBM catching up in >87' with its PS/2 line.
> January 1986, PC-DOS 3.20 supported 720K 3.5".
> Later in 1986, PC-DOS 3.30 supported 1.4M.
Just today, after installing a BIOS-extending floppy controller in
a PC-XT at work, I had to put a 'drivparm=' line in the config.sys
file of the 360K boot floppy (the machine in question has a 360K
A: and a 1.44M B:, and no hard drive) to get the system to
properly recognize the 1.44 drive. The system in question runs
MS-DOS 3.21. The DOS (3.21) Reference manual I looked in had a
switch for drivparm to directly support 720K and 1.2M floppies but
none for 1.44M floppies, so I had to define head/cylinder/sector
counts instead. I also had to pull up a web page to remember how
to set switches 7 and 8 on the motherboard DIP switch for two
floppies (the machine previously has had just the one 360K floppy.
Boot, load the program, replace program disk with data disk, and
Probably by upgrading to DOS 3.3 I could use a simplified drivparm
line in config.sys, but I haven't seen a legal licensed copy of
MS-DOS 3.3 anywhere in the lab. And 3.2 works fine.
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