17 May
2023
17 May
'23
7:22 p.m.
> What they won't handle are DD formats that
don't use the standardPC
> disk controller: Amiga disk, DD Mac disks, etc.
The few external USB drives that I have tried can't even handle most of
the stuff that a standard PCdisk controller can. Their firmware is locked
in to a few specific formats, with no way to access a different file
system, change sector size, etc.
If you know of an external USB drive that does have the cpabilities of a
standard PC disk controller, please tell us what you can of make, model,
supplier, availability, etc.
On Wed, 17 May 2023, Mike Katz via cctalk wrote:
That is because Amiga uses GCR recording rather then
FM or MFM.
Apple2, Commodore 64, Mac 400K/800K, and many others are GCR.
For the Mac 1.4M format, Apple switched to MFM, and it is similar to PC
1.4M, but with a different directory/file system.
Amiga, however is NOT GCR! It is MFM, but without the IBM/WD track and
sector layout. The NEC 765 is designed for MFM with the IBM/WD track and
sector layout, so it is not designed for such a format. There are tricks
to do it, anyway, by changing drive select in mid-read, etc. Far better
to do it with a flux transition device.
--
Grumpy Ol' Fred cisin(a)xenosoft.com