Tony Duell wrote:
Brent Hilpert wrote:
The weak point in this scenario however, is the
torture of programming the
9815 and problems with the tape cartridges and drive of the 9815. Those
What's wrong with programming the 9815? I thogut it was a fairly standard
4-level stack RPN machine.
Let's see:
- awkward editing
- the display does not show you the instruction, you have to list on the
printer to see what you've done
- key-sequence instructions rather than expressive language statements
- very limited data-handling
- limited to no structure to the language
- etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc.
Or how about this: pretty much every lesson learned and development made in
languages and programming of the last 4 to 5 decades is missing.
Considering the machine is 3 decades old, that would partly explain that...
Actually, if you used a larger, more modern, machine as a mass-storage
unit for the 915, you could possibly figure out the structure of the
program storage and eb able to write programs on said other machine and
download them to the 9815. At least that would get round the listing and
editing problems.
Given that the plotter uses HP-GL as the control
language, I began to think
along the same lines as Chuck wrote about a day ago: building a simple
parallel interface to the plotter HP-IB port that does just the data transfer
(minus all the HP-IB device selection, etc. functions) to connect it up to a
Well, the 'device selection' just means you need to be able to assert the
ATN line so you can send a command (it's sent over the 8 data lines with
the normal handshake sequence).
Additional complexity that's not needed in this scenario.
I assume this plotter ahs a 'listen only' mode, where it's selected at
power-on and doesn't need ot be addressed. Many HP plotters do.
Of course you lose some functionality if you do that. Most HP plotters
are HPIB talkers too, they can report the current plot size and pen
position -- you could move the pen around with the buttons on the plotter
and use the machine as a primitive digitiser (put a trace from some other
instrument on the plotter bed, then move the carriage to points on that
trace and read them into the computer). You might well not need this though.
-tony