PDP-11 Still Working In Nuclear Plants - For 37 More Years

Taco Cowboy writes "Most of the younger /. readers never heard of the PDP-11, while we geezers have to retrieve bits and pieces of our affairs with PDP-11 from the vast warehouse inside our memory lanes." From the article: "HP might have nuked OpenVMS, but its parent, PDP-11, is still spry and powering GE nuclear power-plant robots and will do for another 37 years. That's right: PDP-11 assembler programmers are hard to find, but the nuclear industry is planning on keeping them until 2050 — long enough for a couple of generations of programmers to come and go." Not sure about the OpenVMS vs PDP comparison, but it's still amusing that a PDP might outlast all of the VAX machines.

Comments

I cut my teeth on that CPU

[Bucc5062]

The PDP-11/45 was the very first computer I ever worked with at College in 1978. God I hate to sound like an old guy with a lawn, but they just don't make like that any more. I learned RATFOR, Pascal, c, and Assembler during that time. Even later on, thanks to my time on the PDP11 I expanded system knowledge working with the HP1000 and its front panel switches.

Good times....good times.

Re:I cut my teeth on that CPU

[Cassini2]

The microcontrollers are not rad-hardened. The PDP with core memory and 54-series TTL logic will probably survive a small nuclear blast. There are no highly vulnerable EMI susceptable components in a PDP that I can think of. In fact, I think the military has used (does use?) this and the earlier DTL technologies in its missile computers.

Re:I cut my teeth on that CPU

[Anonymous Coward]

Many of us still can program in macro-11. I got tired of ODT though and built a symbolic debugger with DDT that ran in another task.

The pdp11 has a number of possible hacks that can be useful in remotely identifying code. Ever try a DIV on SP, which moves the stack and changes
the program counter all at a go? Mov @offset(r5),pc ? That gives control transfer an extra level of indirection. There are others.
Note the DIV hack works only for CPU models with the EIS instructions.

The pdp11/45 has a 300 ns. cycle time though, corresponding to ~3.3MHz clock speed. Current machines have more like ~3.3GHz.
The larger 11s could address 4MB of memory (a lot in those days). Now a 4GB machine is beginning to look small.
I recall when we got a 22MB hard drive (size and shape of a clothes washing machine; we put Dymo labels under the lights
labelled "wash rinse dry" for fun) it seemed vast. Nowadays it is not unheard of for a home machine to have 22TB.

With all those factors modern machines can be said to have grown by a factor of maybe a trillion.

Still the pdp11 was versatile and allows significant and useful code to run. It is usually programmed in assembler (macro11;
nobody uses PAL11R any more I hope) or Fortran or C. (The original pdp11 Fortran was a nightmare of code inefficiency, could
burn 100 instructions to add 2 integers where the hardware could do it in one. Only the later f4p compiler got half decent code
generation.)

I only ever saw mov -(pc),-(pc) used as a fast clear memory; it traps at the end, but won't get any unmapped addresses.

It was more fun to arrange to handle interrupts in supervisor mode. (Did that too. Needs a lil trick to RTI.)

Re:I cut my teeth on that CPU

[Giant Electronic Bra]

Yeah, I know what you mean. A lot of newer technology is just less good. Verizon 'improved' my phone service so now they 'back up' my contact list. Its great, every month or so they restore some old worthless crap over the top of my contact list on my phone. Ain't progress great? Now I carry around an actual physical address book.

If it ain't broke...

[intermodal]

Honestly, it's a system that works. Everything is seen as disposable today, but really, the only reasons we end up getting rid of systems that works these days are either because of support issues (i.e. Microsoft's end of life abandonment of security updates for older products) or lack of available replacement hardware to swap in for failed or failing units.

Honestly, without the need for protection from security holes related to the Internet (and the accompanying security patches), most office workers could get by on Windows 2000 machines with Pentium III processors with probably less than 1GB of RAM and Office 2000 for the foreseeable future.

Not saying we haven't made advances, but I'm definitely saying that modern closed-source computing (Microsoft, Apple) is a system of planned obsolescence.

Re:If it ain't broke...

[intermodal]

You seem to be equating this laundry list of things running at the same time with "need". Frankly, I'm not convinced that present-day "need" gets any more accomplished than was performed by what we had ten years ago in most businesses with the "needs" from then.

I don't measure productivity in the number of bits pushed or number of programs used. I measure it in how useful those bits were and how much was usefully accomplished by those programs. You're simply justifying bloat.

Re:That's just cruel

[tgd]

So? A "generation" is commonly held to be 30 years; the average child (note: not first-born) being born when the parents are approximately 30. Secondly, TFA specifies two generations "coming and going", which means two ENTIRE generations pass; not just one passing and the second one beginning.

That is 60 years, not 37 years. TFS, if not TFA, which I didn't read, is officially stupid.

Commonly by who?

In virtually all cases, generations are pegged at 20 years. The common "Gen X", "Gen Y", etc are all 20 year spans. In fact, virtually every named "generation" of the last century were equal or slightly less than 20 years.

Even if you go by the average age of first birth, in virtually all of the "1st world", its right around 25. The peak averages are barely 30, and globally its in the low 20's, depending on the source.

So by either definition, there's definitely time for two generations ... and if you're talking about the average time in a given position (which is a more meaningful generation when speaking about engineers), you're looking at more like 15 years -- or time for three.

Re:Dave Cutler's work lives on

[Anonymous Coward]

Microsoft hired him to lead a team that designed Windows NT.

Wow. Way to re-write history. No, I'm afraid that's not how it went down. Dave Cutler developed what ultimately is NT while working for Digital Equipment Corporation. DEC wasn't interested in Dave's creation. Dave unethically and possibly illegally shopped it around. Microsoft was interested. Dave and his entire engineering team left DEC, and went to work for Microsoft, and actually, literally stole DEC's intellectual property and eventually released it as Windows NT. Yes, I am saying that Windows NT is the intellectual property of Digital Equipment Corporation, and Microsoft never paid DEC a red nickel for it.

On a personal note, I am divided about Mr. Cutler. Windows NT might have been the best Windows ever, and NT itself isn't a terrible platform. What Microsoft did to it is unfortunate for users and administrators everywhere, but it essence, NT wasn't terrible. Cutler is an impressive developer... quite amazing... yet it sickens me that what he and Microsoft did was insanely unethical, and no one noticed. Microsoft's main flagship product was STOLEN, and no one noticed, and this is hardly ever acknowledged.