13 Nov
2015
13 Nov
'15
12:16 a.m.
From: Johnny Billquist
Sent: Thursday, November 12, 2015 3:44 PM
However, that is still dealing with DECtapes. I'm
curious about the
ability to deal with LINCtapes, that don't use the same codes on the mark
track (or whatever it was called, my memory fails me at the moment).
Yes, "mark track".
The TD8E do not understand things at all, and
everything have to be done
in software, which is why I'm saying that it will actually deal with the
LINCtape format if you want it to.
Right. The TD8E only sees "single line passed" (= 3 bits of data + 1 bit
of mark) and "four lines passed" (= 12 bits of data + 1 mark code) and is
completely agnostic about the values.
However, more "intelligent" controllers do
all this processing of the
mark track to identify start and end of block/tape, and all other
processing, in the controller. Can you make them read out the contents
and do the processing if you have different control codes?
The state machine implemented in hardware for all the intelligent DECtape
controllers will not recognize the 4-bit LINCtape codes at all, since the
DECtape codes are 6 bits long. You'll just get a MARK Error.
Rich