4 Jan
2002
4 Jan
'02
4:53 a.m.
On Fri, 4 Jan 2002, Christopher Smith wrote:
Yes. But there are some rare exceptions, at least in some of the more
bizarre 8" ones. "Normal" hard sectored uses the same detector fro both
sector holes and index.
I think it was Fred in a previous post
who said that CompatiCard would
indeed do FM, but it's early and I'm too lazy to check right now. :)
Yes
The original IBM FDC card, with the 765 could NOT do FM/SD; it was
hard-wired for MFM/DD. It was not very hard to modify the board to fix
that. In fact, Flagstaff Engineering used to modify IBM FDC cards for
8" operation. I've got a boxful around here somewhere, as well as
extensive blathering by Doctor Marty about his reverse-engineering of
their mods.
Several makers of FDC cards put in the circuitry to get the full use of
the 765. Micro Solutions (Compaticard) was one of the best of
those. Unfortunately, they've abandoned their disk controller and disk
format conversion software lines, and now just make external drives of
various types.
Several of the newer variants of the 765, such as the 37C65, handle the
switch betwen FM and MFM entirely in software. Those will do FM/SD.
Almost any controller card that uses one of those chips can do FM/SD.
--
Fred Cisin cisin(a)xenosoft.com
XenoSoft http://www.xenosoft.com
PO Box 1236 (510) 558-9366
Berkeley, CA 94701-1236
NOTE: My ISP is having difficulties. If you have problems reaching me at
this e-mail address, you can leave a message at:
cisin(a)info.sims.berkeley.edu
fcisin(a)merritt.edu
I am unaware
of such a thing as a hard sectored drive. It is a
controller function.
So the sector holes are in exactly the same place as the
index hole? that CompatiCard will drive an 8" floppy ;)
As will a conventional AT FDC. Trouble is, most of them won't
read/write single-density (FM). However, some of the XT class clone
controllers with an onboard BIOS and selectable BIOS address
will drive
an 8" drive and do both FM and MFM.