2 Aug
2014
2 Aug
'14
2:52 p.m.
On 08/02/2014 02:08 PM, Mark J. Blair wrote:
I thought I already had a computer to plug it in to on
my junk pile,
but those all turned out to be much too new, with PCI slots only.
Thus, I'm looking for some help looking for a machine that I can buy
for running ImageDisk on. I don't want to waste space with any old
arbitrary no-name clone machine; I'd like to get something that has
some collector appeal all by itself, besides its utility for running
ImageDisk with that AHA-1522A.
My advice is to use the motherboard with a built-in controller that
supports 2 floppy drives (some only support a single floppy). Run the
single-density test program. If it passes, you're fine for almost any
common MFM/FM disk format. The only reason for going to a separate ISA
FDC is either non-support of FM or your need to handle 128-byte MFM sectors.
If you're dead-set on using a separate ISA floppy controller, be
careful. Some FDCs are worse than the built-in ones and many later
motherboards with PCI+ISA support and built-in FDCs will not allow
reassignment of IRQ6/DMA2 (e.g. Intel 820 chipsets in my experience).
That being said, a good candidate for support of an ISA FDC as well as
having decent on-board floppy support are the Intel 440BX-era P2/P3
boards. They're still fairly plentiful and won't bog down if you want
to run something like XP, Debian or Win98SE on the same machine.
For example, one of the systems I use routinely is a SuperMicro dual P3
server with a 440GX chipset. It's also got 2 ISA slots, with one
occupied by a Microsolutions Compaticard, allowing for up to 4 drives.
Really, it isn't terribly difficult to set up.
If you want the National DP8473-type controller so that you can write
128-byte MFM sectors (very unocmmon), you can also try DTC, Ultrastor or
Future Domain SCSI controllers, which will do the same thing as an
AHA1522 (same chip). Some of the DTCs have provision for supporting 3
or 4 floppy drives on the same cable.
--Chuck