PDP-11/40 minicomputer running a program

This is a PDP-11/40 minicomputer running a program to move a bit across the console panel from right to left.

This video shows me loading the program using the toggle switches on the console, and then executing the program.

The program is loaded as follows:
001000 Load Address
005000 Deposit
005200 Deposit
006100 Deposit
000005 Deposit
000775 Deposit

To run the program, enter:
001000 Load Address and press START

You will notice that I halt the program by pressing the HALT switch and then restart it by pressing the CONTINUE switch.

The PDP-11/40 computer was made around 1973 by Digital Equipment Corporation.

Category:

Science & Technology

Tags:

• PDP-11/40
• PDP-11
• minicomputer
• vintage
• antique
• computer
• Digital
• Equipment
• Corporation
• DEC

[Wortinguk]

I was a service engineer for these in 1977! Seem to remember the bus (Unibus-16 bits) ran at 2 Mbyte per second and the CPU only a bit faster.

012737 Mov #101, @txbuf

000101

177566 = 'A' on the screen

[Vyggy]

..Cool.

[TheQuindecillion]

Is it at all possible that any of these are still in service? Seems unlikely.

[ChaosKids512]

LOL! I worked on these in the Navy as a CTM! We had to micro-pop them in order to troubleshoot them. Hilarious looking at this now...

[72734695]

I believe it was 1975 or '76 I had one of these (PDP-11/40) running RSTS/E timesharing with BASIC. Used it to drive a phototypesetting machine to set type in Arabic. It didn't have much memory but you could "chain" programs together to get a fair amount of work done.

[gasaxeLTV]

I had an 11/34, pdp-8/e and ultimately moved up to a Microvax II and it all went in the trash years ago.

I still have VMS on TK50 tapes. Maybe I should find some hardware.

[siliconsurf]

you to be a super nerd to program this retard of a machine...

[ARandomNomen]

Sorry about that folks... I didn't realize the comment formatting was going to ignore my line breaks....

@WW - Thanks for posting this video! It brings back a lot of memories. The first two computers I used were a PDP-11/20 and a PDP-11/50. I wish I had some of this old hardware.

[ARandomNomen]

@Membrane556 - The data display on the front panel is the content of Register 0. The program sets the LSB of R0 then loops rotating it through the register (ROL R0). The delay you note is caused by a RESET (Unibus init) instruction following the ROL in the main program loop. The program in assembly language is: CLR R0 INC R0

1$: ROL R0 RESET BR 1$

[gingrinch]

Odd address traps anyone?

[douro20]

You should put an RK05 or similar up top and a tape drive below it...