Happy Birthday, PDP-8

Rick Bensene rickb at bensene.com
Mon Mar 23 13:36:51 CDT 2015

To celebrate the PDP8-'s birthday, Sunday I fired up the PDP 8/e system
with two RK05's, RX01 (Dual), PC8E/PC05 Paper Tape, EAE, 32K, and 2
Serial Ports with SerialDisk running on one of them, and did a complete
set of MAINDEC diagnostics on it just to make sure all was well.  Took
quite a while to get through them all, but they all passed with no

The system was built in 1972, and so it's 42+ years old, and I am
continuously amazed at how well and robustly these machines were
designed.  DIdn't even have to boot OS/8, it was still in core.    But,
just to check, I did boot it off of RK05 using the SW switch (diode Boot
ROM board), and it booted up in just over 1 second.   Those were the

I fired up CHEKMO (Chess) and set the machine playing against itself for
a while - a good CPU exercise.  I then ran ADVENT (Adventure) and played
around in it for a bit, which is a good test of Disk I/O and CPU.  Also
fired up BASIC and loaded a few of the vintage game programs (STRTRK
among them), and before shutting it down (it was starting to get late),
I did a test compile of a pretty good-sized old Fortran program -- that
definitely exercises the disks quite vigorously.  It ls always amazing
how much mass the RK05's push around to move the heads.  The rack
definitely shakes from both drives thrashing the heads around.   

It sure brought back a lot of memories of the summer job I had between
Junior and Senior year of High School where I wrote some high speed
floating point math routines for PDP 8/e with EAE.

Happy Birthday, PDP-8! 

-Rick Bensene

More information about the cctalk mailing list