2 Oct
1998
2 Oct
'98
5:35 a.m.
On Fri, 2 Oct 1998, Allison J Parent wrote:
< We appear to differ only on the definition of
"PC".
Apparently we do. To me A PC is any machine fromthe IBM PC on including
clones.
A valid definition. For purposes of discussion, we're better off with
that definition and including anything that's close enough to run the
average software. I had been referring specifically to IBM's, and to
the fully "bug-for-bug" clones. I should have been far more careful with
my wording, since it apparently seemed to you that I was maligning the
765, when I was actually kvetching about what IBM had done to/with it.
I LIKE the 765. And except for FM access, I can live with the IBM FDC
card. But for SOME purposes I prefer the older WD179x, specifically
including that the "reset on index" makes extra hassles when using the PC
to read some formats that have crammed data (10 512 byte sectors) too
close after index (I advise my customers to try taping over the index hole
on the disk if it can't find the first sector), AND, for the purpose that
started this thread, the track read of the WD is more useful TO ME for
analyzing track content below the sector level.
The only dirfference from 765 to 37c65 is that the
37c65 has ALL the logic
we'd wished IBM to use back then.
Thereby making it MUCH more difficult for somebody like IBM to misdesign
the board.
< The TRS-80 model I did indeed use the 1771 (FM).
Data separation was po
< done, and there were after market boards to patch it.
I know I worked for them too. They were always looking at the cheapest
worst solution. Remember these are the same guys that brought
RAS*/CAS*/MUX across from the main console with bad enough timing that
the EI didn't work most of the time if it had ram.
Even WD's data sheets recommended not relying on the internal data separator.
< and so did the TRS-80 model 3 and 4. But Radio
Shack made some WEIRD
< design decisions regarding use of Data Address Marks.
Deliberate attempt on their part to keep trsdos on their systems only
and part lack of knowledge.
I've sometimes heard that the mischoice that they made for WHICH DAMs to
use was due to a pair of transposed columns in an early WD data sheet.
Any truth? Was it Randy Cook's decision? Or somebody else, in RS?
Considering it was never designed for anything else it
sorta begs the
question... Why blame the cow for soggy cereal?
Good point. My uses are not always "conventional." Such as our crackpot
attempt to mix multiple sizes of sectors on a floppy in order to try to
squeeze just a few more K. "Hey! there's still room for one more 256
byte in addition to the 1024s and 512s" And when we made a WEIRD
distribution format that simultaneously had half a dozen DIFFERENT CP/M
formats on the same floppy - we eventually gave up on the file system for
that and manually selected what to put on each track. Or our
copy-protection that would permit making a usable copy with diskcopy but
would CRASH CopyII-PC.
Or the trackstar128 which could not only read and
write apple disks it
could also run apple software.
That wasn't just a disk controller, it was an Apple ][ clone on a card.
And WAY better that the Quadlink (80% DOA!)
--
Fred Cisin cisin(a)xenosoft.com
XenoSoft http://www.xenosoft.com
2210 Sixth St. (510) 644-9366
Berkeley, CA 94710-2219