At lunch yesterday, I was asked in what year the earliest code ASCL has was written (or was first created). I didn’t know off the top of my head, but thought probably in late 70s. (The earliest I ever pursued was from the 60s, IIRC, & though I found an working email address for the woman who wrote it, which was amazing in itself, she no longer had the code, alas.)

But the question got me to wondering, so in a quick look, here’s what I found: three codes that were initially created in 1978:

Cloudy (ascl:9910.001)
AIPS (ascl:9911.003)
ADIPLS (ascl:1109.002)

All of these have undergone further development and are still in use, as indicated by citations to them in papers published this year.

Are these the most long-lived codes we have? Are there codes that were started even before 1978 that are still in use? Probably. Maybe part of the Starlink (ascl:1110.012) code base? Something else?

If you know of one or can find one in the ASCL with a history that goes back further than 1978, please let us know in the replies.

UPDATE, August 21, 2019

Yes! There is one code that goes back even further, to 1972. Warrick Ball (@warrickball), a postdoc at the University of Birmingham (U.K.), replied on Twitter that the stellar evolution code STARS (ascl:1107.008) got its start in 1971, and the 1972 article which describes the code is listed in the ASCL entry for it. The code is still in use and was cited earlier this year. There’ll be dark chocolate heading Dr. Ball’s way as soon as the weather cools off; kudos to him for finding the answer to this question!