Born on June 25, 1964 in Leiden, the Netherlands
Member of DJOE from 1976 to 1993, membership numbers 11 and 67
Member of ORD-GROUP since 1983
Jurjen has been involved with the ORD-GROUP mostly as a software person.
He spent a significant portion of his life (two days a week over a
period of ten years) at DJOE. To make things worse, he spent his
time at home building the JEC (Jurjen's Eigen Computer).
Although he is the senior member (both in age and in DJOE membership),
he spent most of his energy writing "application" software.
He started with membership number 11 in 1976, but was issued a new
membership card with number 67 after his card was forgotten in the
He donated critical hardware (RAM chips and delay lines) at the
appropriate times. In the true spirit of the ORDINATOR project, these
items were salvaged from the waste bin at his father's work.
We still remember his long hours of tedious keyboard maintenance, all
the while singing happily because he was so deeply in love with
Jolanda, his current wife.
He wrote an efficient but very complex LIFE program for the EXIDY. This
program found an error in the EXIDY's RAM that wasn't found by any of
the RAM testing routines: the particular bit only malfunctioned if it
was left unused for a while.
Together with Niels, he provided the basic ideas (ORDSYS) that grew
into the time-sharing system TS and its never-built successor CHAOS,
loosely based on their JANOS system. Jurjen also wrote our LISP
interpreter and built the SASL compiler (written in LISP!) and
interpreter together with Niels.
He is still very proud of the linked-list implementation of the
multiprecision multiplication routines that were part of the SASL
His interest in the boundary between math and computing science hasn't
changed since: his dissertation
is on cryptology.
After his ORDINATOR period, he obtained some fame in the HP49G
community with the
A personal account of the ORDINATOR was published
in the 25 year DJOE jubilee edition of the Labzwans from 1998.