[SoftTalker]

Well the systems controlling Voyager are quite simple, being 1970s technology. Obscure by today's standards perhaps, but not terribly complicated. 70KB of memory, programmed in Fortran and probably some amount of machine or assembly code.

Edit: apparently, due to the post-Apollo budget environment in the 1970s, the Voyager program had to keep costs down so while some new systems were developed, they also reused technology from the Viking program, not even updating or enhancing it.

"The Voyager CCS and Viking CCS would ultimately have the same amount of memory (just under 70kB) despite the routines and programs for Voyager being much more complex. In-flight programming allowed for new routines and programs to be uploaded regularly in non-volatile memory and eliminated the need for large amounts of memory to be required onboard."

https://www.allaboutcircuits.com/news/voyager-mission-annive...