Linked by Thom Holwerda on Mon 18th Aug 2014 22:39 UTC
Hardware, Embedded Systems

Via TechCrunch:

You want to play Adventure, but don't know how to turn on the PDP-11? These instructions are for booting our dual rack machine from its RL01 drives, although booting the single cabinet machine from the RK05 is very similar.

How to boot a PDP-11. Yes.

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RE[3]: Interesting
by whartung on Tue 19th Aug 2014 18:46 UTC in reply to "RE[2]: Interesting"
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"This would have been more useful if it was walking us through the emulator.

I don't think emulators are that interesting, and they're not even visually impressive. :-)

Honestly: It's no big deal to run decades old software on today's laptops, but in my opinion, it's not that much fun, and primarily it's about fun when running old software.

There is so much truth to this.

On the one hand, I never "ran a PDP", but I did use one for several years in college, a PDP 11/70 running RSTS/E. We had Basic Plus, a C compiler, Fortran, MACRO-11, and Pascal.

My sole experience with it was through the computer labs via 1200 baud terminals. I knew it existed, you could see it through window of the main computer center (it was shoved in a corner, while the vast majority of the room was consumed by the CDC Cyber, with its huge cabinets, monster disk packs, and the band printer that could consume a box of green bar faster than you can hit the stop button).

So, you'd think that if I fired up an emulator, that if I got back to that friendly 'Ready' prompt, and a blinking cursor, that I'd be happy.

But, it's not the same.

Maybe tinkering with the hardware and getting it to work without blowing the panel in your house is interesting. But just having the prompt, that blinking cursor relentlessly asking you "what now?".

Well, it's just not interesting.

The reason, for me, that it's not interesting, is because you're not in the time. Sure, we can look at it, marvel SYS this and $ that. We can ponder the primitive nature of the tools (TECO w/VTEDIT?? No, sorry, it's not missed). We can point and show Kids Today(tm) how awful it was back when we only had 0's, and not 1's.

But a computer without purpose is a room heater.

As a developer, I help the computer bring value. Back in the day, working on the PDP, we wrote programs because that's what we had. We didn't have our own computer, or if we did, we couldn't share it with anyone easily. On the PDP, we could.

My friend and I kept struggling to write a Rogue clone. We ran in to memory limits with Basic, rewrote it in Pascal, and ran in to them again. For development, we would consume three terminals in the lab, one with the editor open, one building the code, one running it. We were privileged to have a source file big enough that TECO would alert us "Loading file slowly...", and we had to page chunks of it in manually. That's why we never exited. That file was 70 blocks, or 35K. We were exploring overlays when we gave up (anyone else remember overlays?).

But it was what you had, the tools you had, the limitations of the system at hand. And we were learning. We didn't even know Pascal, for example. You were in the time with state of the art hardware. Fresh and new, pushing boundaries.

Similarly, a couple years ago, I thought I wanted to build a computer. You know, old school. 6502 CPU, ram chips, etc. Put a floppy disk on it. But then I thought "What would I do with it?" How do I not make it a room heater.

And then you look around at getting the parts. Hmm, floppy disk needs a floppy controller. And how would I even create a floppy today? Oh, you can just use a flash card, and here's the glue logic for that, but "what you should do is use a FPGA for the glue logic, this guy will sell you one for $5".

Pretty soon you realize that you don't need to build this thing at all. You can get a $10 micro controller, all on a chip, with a breakout board. Even more amusing, you can get one with a 6502 or Z80 simulator built in to it! "So, it's just like the real thing."

At this point, I'm seriously in the "what's the point" of this exercise. What IS a computer any more anyway? When you have a half dozen ssh terminals logged in to "the cloud" on virtualized machines over virtual networks. Does computer really have identity any more? At the individual level? Computers are beyond commodity today. I imagine my wireless mouse has more computing power than the micro computers I cut my teeth on.

I ended up writing a 6502 simulator. Got a FIG-Forth running on it, wrote the simulator, wrote my own assembler.

That scratched the itch.

But eventually, I got the Forth up and running, got it debugged, got a disk block interface going, got the OK prompt, and then...that endlessly blinking cursor. "Now what?"

Now what indeed.

Back to work.

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