On Thu, Feb 6, 2014 at 10:04 AM, Ethan Dicks <ethan.dicks at gmail.com> wrote:
Another variant I'd like to try is bringing this up on a DECmate I
with a DP278. I know it's not _exactly_ like a KL8E, but hopefully
the differences are minor enough that the handler is still one page.
I've got a few spare locations in the handler. I'll look into the DP278 and
see what I can do. I may also write an optimized handler for Philipp's
Omni-USB board.
Also, since there is a DKC8AA most PDP-8/a boxes that is rarely used
(sometimes, people use it to drive a line printer
instead of buying an
LP8E card - there's an OS/8 handler for that), I look forward to a
parallel-port version of this - even if it takes a $25 microcontroller
to handle the low-level transfers.
Yes, I had considered a parallel version, but I only have 12-bit parallel
output cards, not any I/O cards...but for an -8/A, that sounds like a fine
alternative. The external hardware could be a minimal 16-bit
microcontroller, I imagine.
Also, I had considered a handler version that operates on address 03/04 by
using some clever escape sequences, much like AT modem commands. You'd need
to use it with a special terminal program, or modify the server to output
non-handler messages to a pseudo-TTY that another terminal emulator is
connected to. This way, *anyone* with a PDP-8 that has just one
asynchronous serial card can boot OS/8!
What do you all think? What would a good choice be for an escape sequence?
It could have a time component in there as well so the symbol rate becomes
part of the "signature" of the sequence.
Kyle