My pdp-11/34 has an Easter Egg! - Page 1
Forum section: electronics / general

author: intabits
author_rank: Frequent Contributor
timestamp: April 01, 2020, 03:02:16 pm
content: While repairing the M7859 board in my pdp-11/04, I learnt a lot about the workings of this board.My pdp-11/34 has the later version of the M7859, and look what it does!

author: rrinker
author_rank: Super Contributor
timestamp: April 07, 2020, 03:51:24 pm
content: That's one of those things I've love to get into, as if I need any more time sinks. I'd love something like that with a front panel - I got an 11/23 running at my first job, but those don't have any fun blinken lights or a control keypad.I don't know what i would DO with it, mind you, but it would be neat to have one in working condition. Emulators just aren't nearly as interesting as the real hardware. I'm sure I can rather easily emulate that 11/23 with RSX-11 and FORTRAN, but it's not the same.

author: intabits
author_rank: Frequent Contributor
timestamp: April 08, 2020, 01:35:45 pm
content: I've got a couple of other PDPs that have toggle switches instead of keypads.They look more "blinkenlights", but also more of a pain to actually use.But if you like blinkenlights, there is an emulator that you might actually find interesting - my IBM 7094 emulator.See this thread:-https://www.eevblog.com/forum/vintage-computing/an-emulator-for-the-ibm-7094-mainframe-computer-(big-iron-circa-1960)/It's easy to use, all driven by demo scripts where you just click stuff...And if you like Fortran, that's covered too!(not hard to compile and run your own code by copying and modifying one of the demo jobs and source)link to the video:-

author: rrinker
author_rank: Super Contributor
timestamp: April 08, 2020, 09:20:56 pm
content: Somewhere I saw and tried an IBM 4381 emulator, or maybe is was a SYS/390 emulator, that took me right back to college. My last two years, they installed a 4381 running MUSIC for everyone to have an account on. And scripting things with REXX... those were the days. I unfortunately did not have an account on what was a DEC 10 when I started, later upgraded to a DEC 20, as that system was pretty much reserved for CompSci students.

author: intabits
author_rank: Frequent Contributor
timestamp: April 09, 2020, 01:36:25 am
content: I was a systems programmer on IBM gear for 15 years. Over that time we had 370/115, 4341, 4381, 9320 (an S/390), but all were without blinkenlights. Missed out on that era.And did a lot with REXX during that time.Never worked with DEC gear, but I've collected a bunch of it.I've actually owned a couple of System/360 model 40's, which I scrapped for the gold (among others).I really wish I had kept the consoles from them - covered in switches and lights.

author: intabits
author_rank: Frequent Contributor
timestamp: April 12, 2020, 01:59:48 pm
content: Some people thought that my earlier video showing an "Easter Egg" in my PDP11/34 was an April Fool's joke.In this video I go hunting inside the machine for the Easter Egg, to see if it's for real or just a joke.In the process, there's also some interesting other features revealed.

author: MK14
author_rank: Super Contributor
timestamp: April 12, 2020, 03:10:45 pm
content: In the latest video (the one, immediately above this post), at around 12 min 50 sec, and later. I was wondering what programming language/compiler/IDE and graphics creation software for the images, you used to make the amazingly good quality console "emulator", appear on the screen ?Was it a quick/easy way ?Also, if it was an April fools joke, you got me (I'm NOT particularly knowledgeable about the specifics of the PDP11/34 hardware schematics, so could be more easily fooled). But if it wasn't an April fool joke, you didn't get me, better luck next time.(I know if it was or wasn't an April fool, but I'm NOT revealing here, to avoid spoiling your thread and videos).

author: intabits
author_rank: Frequent Contributor
timestamp: April 13, 2020, 01:58:26 pm
content: It was done in Delphi, which I use for all programming in Windows.The process was quick and easy - at first.I just slapped a photo on the form, then positioned some 7 segment and LED components (that I easily found on the web) over it.And the result was more than acceptable, though it was obviously an emulated console.But when I wanted to place the highlights over the buttons, I decided to use the graphics library "Graphics32", which can do very nice graphical stuff,such as alpha-blending, anti-aliasing, gradients, sub-pixel resolution, resampling and a lot of other stuff that I don't understand.I've used Graphics32 a few times before, but it always makes me work for the result I want, though I finally got there.I ended up completely rewriting the 7seg and LED components to work with GR32, and got a much improved appearance.For example, a radial gradient on the LEDs, together with anti-aliasing makes them look quite real.And the original 7seg component didn't have the 8 degree slant that real displays have, so I added that while I was in there.Glad that I did/didn't get you with the first video!

author: MK14
author_rank: Super Contributor
timestamp: April 13, 2020, 02:08:10 pm
content: Quote from: intabits on April 13, 2020, 01:58:26 pmThanks, that is very nice to know!I hoped, it was something readily available, quick and easy like Delphi (or Lazarus/Freepascal, etc etc).I've heard about the available libraries, with displays, but don't remember trying them.Your displays look very lifelike (in the video).That's a very effective way of doing things like emulators, or showing the status of connected devices.Genuine, vintage computer items. Seem to be getting ever more scarce, expensive, faulty (decaying capacitors etc), and too bulky. So, emulating them on computers, is getting ever more tempting.