Re: floppy.ko

["H. Peter Anvin" <hpa@zytor.com>]

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