Comments on: Annoying Computer News

By: Badtux

Badtux — Sun, 05 Oct 2014 06:51:49 +0000

Kryten, Kernighan and Ritchie wrote the “C” language when they were involved in porting Unix from the PDP-7 to the PDP-11 because they didn’t want to re-write everything into a different assembly language again, it’d been enough of a PITA the first time. That is why virtually every concept in “C” maps directly into PDP-11 assembly language. I used to have the PDP-11 architecture manual somewhere around here (it was the computer we learned assembler on back in the late 70’s at the university that I attended) and looking at the original “C” programming language, almost every statement in the language (even auto-incrementing pointers being used to walk down character arrays) mapped to a single PDP-11 instruction.

Thus why I call “C” the world’s most sophisticated PDP-11 macro assembler ;).

What that does emphasize, however, is just how pleasant and well designed the PDP-11 really was, since the “C” language is now the world’s most popular language for writing low-level code (thanks to the success of Linux, amongst other things, but still) despite not mapping well onto the hacked-up Intel assembly language (which is ridiculously nonorthogonal and a PITA to optimize for). Nowadays I only drop down to assembly language when I’m dealing with something ridiculously limited like a PIC chip that has 4K words of program memory and no timers or interrupts, where everything I do has to be cycle-counted state machines to make the timing work. But that’s another story.

By: Bryan

Bryan — Sun, 05 Oct 2014 05:41:26 +0000

In reply to Kryten42.

At the school I taught at I administered the PDP-11, but it had ATT Unix on it [free education license]. It was a breeze compared to working with the original Data General Nova 3 because it had the memory and disk resources to keep everyone moving at the same time, as well as a 9-track tape for loading and back-up. It could also output to the line printer at full speed. We shifted a lot of the student load off the IBM 360 and got to move away from cards for everything except the COBOL and CICS courses. Good times and no reason to just dump them – if it ain’t broke, don’t fix it. The PDP-11 has been the standard system for nuclear power forever, and there is no good reason to risk something new.

I took drafting in high school and had the tools, but my skills were only adequate as far as I was concerned, even though I took top marks. Now I can do the job with decent software programs that can make up for my weaknesses. I know what I want, but my hands don’t want to go along with my mind when I try it freehand.

The ability to click and have the output go to the plotter is a wonderful thing for me.

By: Kryten42

Kryten42 — Sun, 05 Oct 2014 04:28:09 +0000

LOL yeah. 😀 True about the PDP-7 (and the games bit!) 😉 😀 When I started the COT, we had a PDP-11/03. One of the first things a group of us did was port the original “Colossal Caves” text adventure game to the PDP-11 running RSX-11 AND made it multi-user! Took 4 of us about 8 Months during our spare time. The IT Manager allowed us to have access after school hours & weekends, and he got involved about midway through. 😀 We learned a hell of a lot! 😀 Then we ported Star Trek, but it wasn’t finished because the school got a brand new VAX 11-750 from DEC! And that was far more interesting! My group hacked the supposedly unhackable VAX in a month! LOL Was easy, when you know hardware and electronics. From a purely s/w stand point, the VAX was pretty secure. 😉

Hey… want a laugh? (or a job in Canada?) 😉 😀

I know from working for HP in late 90’s that they were pissed because they wanted to kill the PDP-11 deader than purple suede shoes! But GE and a couple other major companies had news for them! LOL They said they planned to use them until 2050! And that was that! LOL I did a quick Google and found this posed to a Canadian IT board last year:

“ChrisGE is offline
Join Date: Jun 2013

Greetings from GE Canada!

I would like to reach out to you to let you know about a fantastic opportunity in Peterborough Ontario Canada for a PDP-11 programmer. The role supports the nuclear industry who has committed to continue the use of PDP-11 until 2050!! Yes I know this is a hard-to-find (existing) skill. We will also consider programming experience with other assembly language. If you are interested, or know of anyone who is, please feel free to email me at chris[.]issel[@]ge[.]com
Thanks!”

(email edited by me).

I am still laughing over that! (I don’t like HP either!) LOL

Actually, Mentec in Ireland have the LSI-11 rights. 🙂

Drafting was a big part of the COT! And VERY strict! They measured everything! Even the text had to be a precise size and shape! Spaces between lines, thickness, radius of bends, pad size & shape were measured, and woe betide you if you hadn’t properly taken current or LCR into account! I am (smugly) proud that I scored top marks in that (98% – a high distinction)! LOL 😉 And it did come in very handy over the years.

By: Bryan

Bryan — Sun, 05 Oct 2014 01:27:26 +0000

You didn’t need the sweep second hand on your watch to time program execution with 1.0, Badtux 😉

I did the tabletop version with an old plastic dishpan and some tools for developing photographs as well as a surplus military gas mask, because even without the air bubbles the etchant was foul and I couldn’t move air fast enough to avoid it. My neighbors thought I was really strange when I did it. I had conversations with the local cops and firemen on more than one occasion, but it wasn’t illegal and I was following the manufacturer’s directions. I even took out my soft lenses and wore glasses because I wasn’t sure the stuff wouldn’t affect them.

Fortunately there were press on designs for ICs and and other components so I didn’t have to depend on my nonexistent drawing skills for anything other than lines. Later I mastered the use of the system where you mimicked the photographic system, but it didn’t save as much time and effort as I thought it would for one-off projects.

Both Unix and C owe their existence to an unused PDP-7 in the bowels of Bell Labs, but that’s just history and can be ignored. [What some people will do to play games is amazing.]

By: Kryten42

Kryten42 — Sat, 04 Oct 2014 20:18:09 +0000

Part of the COT course was learning how to design and make your own PCB’s. We had to make our own sealed UV table and etching tank (a narrow fish tank with thermostatically controlled heater & air pump with a silicon tube with 2 rows of small holes equally spaced and sealed at the end. It was in a sealed cabinet with an air filter/extraction system (because whilst air bubbles speeds up the process, it also blows the vaporizing etchant into the air! A bad thing!) There are much safer etchants now, even environmentally safe. 🙂

So long as you only need a single or double sided board. Multilayer boards have to be specially manufactured of course. But back in the late 70’s, they were not even a dream yet! LOL

I made my own solder station with an old electric thermostat controlled frying pan for the solder bath and a drill press with an adjustable board holder. 🙂 You could buy a cool tool that would snip and crimp the component leads at the same time. Stopped things falling out while soldering! 😀

Those where the fun days! 😀

As for Java, yeah I started with v1. It sucked (and not just speed!) LOL

LOL badtux! 😀 Actually, DEC used BLISS for the PDP’s mostly, and VMS (for all the OS utilities anyway). 🙂

By: Badtux

Badtux — Sat, 04 Oct 2014 06:10:45 +0000

The first version I used was 1.1. It was… ludicrously… slow. I cannot imagine how slow 1.0 must have been…

“C” is, of course, a macro assembler for the PDP-11 ;).

By: Bryan

Bryan — Sat, 04 Oct 2014 04:35:23 +0000

I was using 1.0, so you know it was slow unless you were using Sun equipment.

C was definitely a welcome replacement for the assembler I was occasionally having to write to get things to work at a decent speed.

Java is definitely useful these days, so I can understand his interest.

By: Badtux

Badtux — Sat, 04 Oct 2014 03:16:21 +0000

Yeah, the early versions of Java were *ridiculously* slow! As in, pretty much unusable. Then they got the JIT bytecode compiler working in 1.4 and suddenly it was usable. Still slow, but usable. The latest versions have been optimized even more, plus the hardware is ridiculously faster now than the Pentium 233 that I was using back then, so using Java is no longer a penalty box. Still not useful for stuff that needs direct access to hardware, of course. That’s why “C” exists…

By: Bryan

Bryan — Sat, 04 Oct 2014 02:10:46 +0000

I learned it the same way except I had the printed Sun manuals [and a promotional coffee cup]. They were advertising it as a cross-platform , more secure, replacement for C in its first iterations, and it did start out much closer to the C model.

The early versions were too slow for the work I was doing so I left it behind.

Perl and PhP are well beyond the borders and need to be seriously reined in to be reliable. They absolutely require defined standards to be maintained and to ‘play well with others’.

I’ll pass along the Javaworld recommendations that Kryten mentioned.

By: Badtux

Badtux — Fri, 03 Oct 2014 17:59:09 +0000

Unfortunately, Bryan, I learned Java via the school of hard knocks. As in, I joined a hardware company because I was an expert on the particular kind of hardware they built, and the first thing they did was say “Oh, and here’s this massive hunk of Java code, we need you to implement functionality X, Y, and Z for controlling our hardware.” From there it was keeping the Sun Java docs open in my browser window while I learned enough of the language from reading the existing program to function, Java is vaguely C-ish so that worked for me, I just mapped Java concepts on top of C concepts, mapped the object model to the Python object model (which I’d just finished mastering) and went from there.

Regarding best practices, that is the same regardless of the computer language (at least when you’re talking about object-oriented computer languages), I use the same best practices in Java that I use in Ruby, Python, or C++. Perl and PHP are a bit… special… because their syntax is so loose and makes it so easy to shoot yourself in the foot, I use a more strict set of rules there. There are special rules applicable to particular problem domains, such as “separate out the business logic from the presentation” (otherwise you have a pain in the butt when you want to go change the presentation because people want the GUI to look or operate differently), and “make everything an API except presentation”, but those are all language-independent too, though some languages make it harder than others (PHP, GRR!!!!).