Re: floppy.ko

From: H. Peter Anvin
Date: Wed Apr 18 2007 - 00:41:03 EST


Gene Heskett wrote:
On Tuesday 17 April 2007, H. Peter Anvin wrote:
Gene Heskett wrote:
I have the usual fd0, a 3.5" 1.44 drive, and fd1, a 5.25" 720k drive in
this machine, both are enabled in the bios with the correct types being
set there.
A 5.25" 720k drive?! That's not a PC standard drive -- 5.25" came in
180K, 360K and 1200K varieties, whereas 3.5" came in 720K, 1440K and
2880K varieties (not including superfloppies.)

-hpa

It sure is a std drive, Peter, although many of the later ones that were set up as 1.2 megger's by the pc crowd who have access to a 500 kilobaud controller, could have the 360 rpm spindle jumper'd back to 300 rpm, and when fed with a 250 kilobaud controller (WD177x/277x/279x family, which includes the Fujitsu MB8877), they are perfect 720k devices and are spec'ed that way by the makers. Many of the older full height Tandon 100-4's could also step quite a few tracks closer to the spindle & I ran them as 765k drives by using 84 tracks. I even have a chinon that will make 86 tracks most of the time.

These were all quite common in the middle '80's. Before your time I suspect.


I know they were quite common, but they were not a standard *PC* accessory. (FWIW, 1200K PC drives could also read/write 720K, which allowed you to use non-HD-rated media.)

(And no, this wasn't "before my time".)

-hpa
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