On 2015-12-17 00:51, Will Senn wrote:
All,
I was watching an old PDP-11 video when, seriously, I came across an
explanation of programming that involved wire snips. It was interesting
and brought home to me the concept of memory pages and such. I thought I
would share the screen shot with y'all. If it doesn't come through
imagine a guy with a pair of wire cutters snipping off diodes from a ROM
card for a PDP11. Is this really how y'all programmed back in the day :)?
Not really. Diode roms would be usable for bootstraps, but not much
else. And you normally programmed them once, and then you just had them
there for years to come. Really short snippet of code that's read only.
Same idea as any other ROM.
Not sure how you would see any connection between this and memory pages.
For programming, you normally have RAM (or CORE), and an operating
system with various tools, such as editors, compilers, linkers and so on...
If you telnet to magica.update.uu.se, you'll be connecting to a real
PDP-11/70 that is online. That's a machine from 1975. Now, it's running
RSX-11M-PLUS V4.6, which is from 1999, but the original version of
RSX-11M is from 1972 or so, so you'll get a good idea how programming
was done "back then" by checking there. But it's not that exciting,
really. It's pretty much the same as today.
Is it possible to single step through a machine language program (such
as the bootstrap loader) that was entered using deposit commands as it
loads another program (such as the absolute loader,
which this particular diode ROM represents) and similarly step through
the absolute loader itself as it loads something like DEC-BASIC from
paper tape, and if so, what does that process look like in SimH terms?
This is just plain memory like any other. Of course you can single step
through it.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
_______________________________________________
Simh mailing list
Simh@trailing-edge.com
http://mailman.trailing-edge.com/mailman/listinfo/simh
