Greetings all...
I have been pondering something and would love to receive feedback from
you. The thing
is, I would like to have something pdp8-ish that would allow me to play
a little bit
with the programming languages that were available for these machines,
FORTRAN 4K and
FORTRAN IV in particular. Now, I would love to be able to time some
FORTRAN jobs just
to get an idea about what it was like back then. I am aware of PiDP-8,
simh, as well as
SBC6120, SBC6120RBC.
I happen to have three VT78 cpu boards (sans the RAM board) and two
vt278 cpu boards.
All were in rather sorry condition; I picked them up from a junk pile
that was stacked
several feet high and in which the contents were mostly random. Thus,
the VT78 boards'
components were scratched and in fact two of them are missing the
control panel ROM chip.
Otherwise they are complete, but I am missing the RAM boards. The VT278
boards
were further abused by someone who yanked out the oscillators and a few
TTL chips,
damaging several traces, which I have now repaired. Alas, only one of
them has the
HM6120 cpu chip, and I do not know if it is good or not. Both are
missing the SMC5037
CRT generator chip. Other than that, they are complete.
So, now that we all know what I have, let me say out loud what I've been
thinking:
If I try to build actual hardware:
I've read that the VT278 has serious software compatibility issues with
older software
due to the use of the HM6121 I/O chip. So even if I get an adequate
keyboard, buy the
CRT chip and manage to use it to drive a monitor, I would need an
original floppy drive
system and media, because I do not have the DP278 serial comms board
that would allow me
to send the VT278 a program to run;
For the VT78, I would need to hack a memory board, and, since it can be
coaxed to accept
a program to run if it is fooled into thinking that it is loading a
program from an
MR78/paper tape, perhaps I could make it boot something. I would need
to wire-up
and arduino or something like it to translate the keyboard and display
terminal
chatter in the serial console into something usable. But, that's three
hardware
projects (memory board, MR78-like contraption, microcontrolled serial
console
translator)...
The last hardware option is to go and make an SBC6120RBC; I would need
to buy
programmers for the GAL/PAL devices, and I've heard that not all
programmers can deal
with the kind of chips used in it. And, if it turns out that the HM6120
chip that I
have is bad, I would have to hunt down one of those rare beasts.. It
would be awesome, though,
to have an SBC6120RBC up and running, and be able to time actual
hardware running
FORTRAN.
And then comes the emulation option, with the PiDP-8. I have to say
that the emulation
of the blinkenlights is very, very attractive to me, and this option is
a no-brainer
hardware-wise.
So... am I missing something in my estimation of the effort involved in
these options?
What would _you_ do?
Carlos.
