Computer History: DEC PDP-11 CPUs and Architecture

In this computer history episode I delve in the timeline of processors released by Digital (DEC) for the PDP-11 computer. I also spend some time talking about the different data bus types as well as the internal architecture (and performance) of the processors.
The PDP-11 architecture was quite ahead of its time when it appeared in early 1970s. The processors were popular before 8 bit bytes was a common data unit and before hexadecimal was the go to number representation in computing (DEC still used octal numbers at the time). While initially they could only see 64Kb of memory towards the end of it is life time, PDP-11 could access 4Mb of memory. Using memory mapped IO was also quite ahead of its time as well.
0:29 1972 - KA11
1:45 1975 - LSI-11
2:42 UNIBUS vs QBUS
4:15 1979 - F11
4:42 1983 - J11
5:23 Architecture and Performance
Photo credits:
gunkies.org/wiki/PDP-11/20
gunkies.org/wiki/KA11_CPU
www.psych.usyd.edu.au/pdp-11/t...
www.psych.usyd.edu.au/pdp-11/m...
www.corestore.org/1120.htm
QBUS: gunkies.org/wiki/QBUS
ARCH: programmer209.wordpress.com/2...
ARCH: pdos.csail.mit.edu/6.828/2005/...
www.wolfgang-houben.de/faqpdp1...

[@harryseldon362]

My first high school computer class was on a PDP-8. I eventually became a computer programmer and work on DEC systems. I remember really liking it and I learned a lot. Those were the good old days.

[@b.baggins8893]

About 40 yr ago I was working with System Industries in Europe. We sold mostly our SI 9400 controllers with SI 9775 Winchester Hard drives. The controller had 4 ports to connect mixed PDP11 and VAX systems not only to a RAID Database, but also served as the fastest computer interconnect. Those system admins smart enough had many benefits and cost savings. But DEC didn't want to allow a mixed Hardware setup and limited their Warrenty.

[@PicaDelphon]

I love me some Classic Digital Electronic Corp Information, This is how I learned working on The In's and Out's of Computers in the 70's.. Love to see more. Yea got a New Sub, that love the Classic Basic MINI / Workstation / Server Computers..

[@LJ45Chimera]

Always great to see a PDP11 video pop up :). Very informative, Thanks

[@MicrobyteAlan]

Interesting thanks for the memories

[@pdppanelman5889]

Rod Smallwood - digital equipment corporation - 1975 to 1985

[@alexandermirdzveli3200]

Very interesting video. Thanks a lot!

[@pdr0663]

I believe the LSI-11 QBUS was only 18-bit. The 22-bit version came later.

[@sbheavyken]

That's right

[@ji-wookim6534]

How does the PDP-11 handle conflicts (when two devices are already using it) and a third device want to use it?

[@apogeedata]

I’m sorry to say but the PDP 117- never came in a BA11-K type enclosure😂😂😂