On Thu, 25 Mar 2004, Bill Yakowenko wrote:
Has anybody out there written drivers for the
WD1793 floppy
disk controller chip? I've been doing that for fun, and have
hit on a very strange problem with the 'read track' command.
It seems to work just fine, returning a stream of bytes that
includes the data for each sector, until it finds a byte with
a value of $29 (or 29H, if you prefer). From that point up
to the next address mark, it gets garbled data. No other data
value seems to have any odd effect. 'Read sector' returns
the right data with no weirdness.
Are you sure it's not a matter of a bad sector on the disk?
--
Sellam Ismail Vintage
Computer Festival
Bill, Sellam's point would be my first guess as well. Are you checking the
status register after the read to see if any errors were flagged during the
operation? You didn't explicitly say that the event happens on ANY track or
sector containing a $29... are you seeing this behavior on one sector, or
all over the disk? --Patrick