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Ancient computer DEC PDP-8 50th anniversary next week

5K views 22 replies 10 participants last post by  dave604 
#1 ·
Many years ago, the Digital Equipment PDP-8 was a popular low cost minicomputer, often found in business, schools and labs. It had a 12 bit word and while much less powerful than the mainframes of the day, it was entirely suitable for many tasks. It was essentially the beginning of low(er) cost computing. While not exactly a "home" computer, some found their way there, after being retired from their original use. There was also a microprocessor that ran the PDP-8 instruction set.

The 50th anniversary of the PDP-8 is March 22.

BTW, many years ago, early in my career, I used to maintain a PDP-8/i.
 
#3 ·
I worked on PDP 8,9 and 15 before the PDP 11 came on the scene. Message switching and hybrid computing.
The original PDP 8 with the memory cards visible through the smoked plastic " brain box"
Fan fold paper tape.
DecTapes.
The different colour keys on the front panel depending on which exact model.
Decus and the enormous amount of free software available.

Good times!



Stampeder. The VAX -11 was the direct descendent of the PDP-11 Two generations away from the PDP-8


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#5 ·
I can't remember what version of the hardware we were using but throughout most of the 80's my office (government) was on a VAX system, their All-In-1/email system (yes it included a Chat type function) and just about everything DEC. Digital Equipment Corporation was a huge operation back then, rivalling IBM. Looking back now it makes one wonder where today's tech. giants will be in 50 years. Just about everything in IT is highly ephemeral. Most of yesterday's companies are gone now. Anyone remember Wang for word processing for example or Commodore? Their success was fleeting.
 
#10 ·
Same place I am ....Freedom 52 ....15 years ago!

IBM 082, 401, 1401, 7010,, 360-20,, 360-30, 360,,,,PDP 11, Dec VAX/VMS, Client server DEC Alpha's, Wang Mini, Burroughs, NCR...IBM PC and others. It was a pain to maintain applications on all that.
HappY I am done with it. :) (Somebody started this! I couldn't help myself)
 
#6 ·
My first real programming experience was on a VAX-11
I also worked on the VAX 11/780, several PDP-11s, a variety of Data General Nova & Eclipse models, Collins C8500 and PR1ME computers. Back in those days, I was a technician repairing & maintaining all those systems.
 
#8 ·
The PDP-8 was popular for Unix. The first Unix system I used was a PDP-8, way back in second year university. We used it to cross compile programs for a Motorola 68000 processor, if anyone remembers those.* The PDP-8 was a rather unusual beast since it sat in a room next to the computing lab and not in a sterile, secretive, far off computer center administered by IBM trained operators. The PDP-8 administrator was a rather hip looking dude named Maji, who later on became the university's head of IT.

*The 68000 was a very well designed processor, much better than the Intel 8086 but IBM decided to use the 8086 for their PC. This helped cause the eventual demise of Motorola's 68000 line and the incredible success of Intel and its x86 processors, which are still used today.
 
#14 ·
WOW ... there were computers in 1973 ;)

Our lab had a number of PDP-xx machine. One course was to r/w hard drives in assembler. Next semester we learnt they had MACRO's for that ..... sure they could not tell us that first LMAO

The current crop cell phones are a million times more powerful that PC in the '90
 
#15 ·
PCs were about 10-15 years behind mini-computers in power and technology so both statements are roughly correct. The first mainframe I worked on was about as powerful as the first IBM PC, introduced about 20 years later. The mainframe had 48KB of "core" memory, a card reader and several tape drives. After a couple of years, it was upgraded with a 5MB hard drive, like the IBM PC but the mainframe hard drive was the size of a refrigerator and had removable platters. Prior to adding the hard drive, programs that were too big (over about 100 lines of code) would make it would run out of memory and crash.
 
#16 ·
Now you've trashed the thread. Our memory was smaller than your memory. Our IBM 1401 had 8K memory and I used the 132byte printer buffer to enhance a program when no memory was left. exec...jump to print buffer...exec...jump out of print buffer. ;)
30 other programmers didn't think of that.
 
#17 ·
^^^^
I seem to recall the PDP-8/i had 4K 12 bit words, but my memory is a little fuzzy. ;)

Anyone else here remember the PDP-8 RIM loader, where you had to toggle in and execute several instructions, to boot from the hard drive?
 
#19 ·
Hard drive....on a PDP-8! You toggled in a boot loader which read a paper tape into memory. At EOF on the tape the boot loader did a jump to the start of the program which IIRC was at something like address 64 I page 0. Fancier late model PDP-8s the boot loader could read from a DECtape.
Yes 4k 12 bit words with IIRC an expansion to a second 4k which you had to page into to use.


I just found a site www.gunkies.org with all the PDP-8 details. Up to 32k and the later versions could have hard disk

Sent from my iPad using Tapatalk HD
 
#23 ·
My dad had a PDP/8 in his small engineering firm's office. Sometimes when I would visit he would help me load a moon lander game from paper tape and then let me play the game. The interface was a teletype. I never managed to land successfully - it was too hard for a 10 year old! I remember being amazed when they got a DEC tape reader - it looked so futuristic.
 
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