This question was asked during my Boot Camp presentation last fall in Boston, and over the past 35 years dozens of times people have asked, how big is VMS? That translates into “how many lines of code are in VMS”? I thought it was time to at least make a stab at pursuing some insight into the answer. I wrote some command procedures to count the number of source lines in .B32, .B64, .C, .MAR, .M64, and .S files. Not counted are blank lines and lines beginning with the standard comment characters and miscellaneous directives for the particular language.
↫ Clair Grant
As always with the ‘lines of code’ metric, there’s some real arbitrariness going on, and in this case that means things like excluding networking, which to me seems like a core part of an operating system, but alas, choices need to be made. The final tally for lines of code, as per the definition used in the article, in the most recent version of OpenVMS, version 9.2-3, is almost 1.9 million. Do with that information as you please.
What’s really fascinating, though, are the deltas between the versions investigated in this article: V6.2 (May 1995, port to Alpha), V7.2 (February 1999, kernel threads, 64-bit APIs, Galaxy, and more), V8.2 (February 2005, port to Itanium), V9.2-3 (december 2024, port to x86). Going from one version to the next, roughly 400000 lines of code were added each time – the article doesn’t theorise about the consistency of this number, and I suspect it’s mostly just a fun coincidence, but it does jump out.
I don’t know about the consistency of the number but my guess is that the bulk of the code between releases is mostly hardware drivers. Notice the big jumps in ACPI, SCSI, and LAN. I know DRIVERS is listed separately but the number hardly changes so this must be mostly the interface and not the drivers themselves.
Also, I assume LAN is networking. I know he said he was excluding networking but, based on the rest of the list, he may mean client applications and/or utilities.
I have not done any analysis. This is all just a guess at first glance. It is impressive how static some of those modules are given the elapsed time involved.
A company I used to work for was huge into DEC Alpha systems. We used Windows NT on them but they booted natively into VMS and so I was exposed to it at least a little professionally. It is fascinating that it is still kicking after all these years.
My company still uses OS/2 (i am just a worker and not the owner). The company is valued at several billion euros. Fun fact.
What is your company running on it? Back in the day OS/2 was used a fair bit on ATMs.
Last release: ArcaOS 5.1.1 / February 16, 2025; 43 days ago
Nothing wrong with still using it
I have fond memories of OS/2 and would pay for an ArcaOS license if it was a bit cheaper. The personal license is $139 and it is $70 per year to keep getting updates. That is pretty steep compared to the $0 I pay for Linux now. If the $139 was perpetual, or if it was more like $50 for 3 years, I would probably go for it.
I may be one of the few people that really liked the Workplace Shell. Very dated fonts aside, the Warp 4 interface was great as well. The OS has hardly changed since the 90’s but what they have done is add UEFI, ACPI, and driver support to make it more viable on a modern machine.