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 inA 5.25" 720k drive?! That's not a PC standard drive -- 5.25" came in
this machine, both are enabled in the bios with the correct types being
set there.
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.