13 Jun
2010
13 Jun
'10
10:17 a.m.
While I do understand that an external data separator is a good thing,
I was one of those who did a design using the internal data separator
using the WD1771 (and later National) chip. It was on a M6800 system I
did some work on, and it seemed to work OK for me. I was using
(originally) 35 track Seagate drives, but later used 40 track ones.
I've heard many complaints about the TRS-80 model 1 disk controller which
used a 1771 with the intenral data separator. But I ran a model 1 for
quite a few yesrs with a 'stock' expanison interface (no doubler, no date
separator mod) and never had a disk error. Yes, I kept the heads clean.
Yes, I checked the drive speed from time to time (but never had to adjust
it).
I had many, many, more problems with an Apple ][ I was using...
[...]
Just my experience. I still have a system operational (I haven't
turned it on in a few years, but may soon). I also interfaced various
hard disks. What fun. It was 1976 and also worked on Qume
(daisywheel) printers (it only takes a single PIA to in terface to them!).
I remember the Qume printers with the 50 pin card edge for the interface
connector. IIRC, you specified the print wheel position, how far to move
the carriage, etc on seperate sets of data lines. But it's been a long
time...
-tony