24 Jul
1998
24 Jul
'98
1:02 p.m.
Date: Sat, 25 Jul 1998 00:23:07 +0100 (BST)
So, can a standard XT controller be used for 8" drives?
For reading 8" disks, of course. My PC/XT on the desk here has 2 each
of
360K 5.25" drives, 720K 3.5" drives and
1.1Mbyte 8" drives (double
sided,
double density, 77 track). Pity the controller I've
got has problems
with
single-density operation. I really must fix that
sometime, but it's not
urgent, as my PERQ has a much nicer floppy system...
For once, I used the correct terminology :) Compared to SCSI, all
IDE controllers and most non-IDE/SCSI MFM drives require very little
configuration. That's what I meant.
What? ST506 drives (I assume that's what you mean -
MFM is an encoding
system, not a controller interface) have drive select jumpers at least.
And often other ones.
And the original IBM XT hard disk controller (later version only?) has
a
set of jumpers to select the drive type. I believe you
can solder a DIP
switch in place of them if you want.
So does this mean 1.2MB floppies use a lower bps than 360K disks?
Which controllers were these? I ought to watch out.
I've seen some controllers that can't correctly
handle the 300kbps data
rate (produced by putting a 360K disk in a 1.2Mbyte drive turning at
360rpm). Of course the so-called manuals don't mention this anywhere,
but
it was obvious from a logic analyser on the Write Data
pin during
formatting that it was actually using 250kbps.
Where can the connectors be gotten cheaply? I've seen them for a
couple of bucks each. I really ought to perform some maintenance.
Is there anything I need to know, or can I just snap those connectors
on and trim the cable?
That problem is trivial to solve if you can crimp IDC
connectors. Why
do
people persist in refusing to modify PC parts - even
cables?
-tony
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