[Info-vax] CRTL and RMS vs SSIO

[Lawrence D’Oliveiro]

[I previously posted something similar, but it never seemed to make it into Google Groups.]

On Monday, October 11, 2021 at 9:54:19 PM UTC+13, John Wallace wrote:
> DLM a standard part of Linux? But *which* DLM, *which* Linux? 

Turns out it’s a standard package in Debian <https://packages.debian.org/bullseye/libdlm3>, and therefore in most Linux distros. I thought there had to be an accompanying daemon, which is mentioned here <https://packages.debian.org/bullseye/libdlmcontrol3>.

The API is about as faithful a copy of the original VMS one as it is possible to be <https://manpages.debian.org/bullseye/libdlm-dev/dlm_lock.3.en.html>: the lock modes match one for one, it uses the term “AST” for the completion notification, and even the timeout is measured in centiseconds (good old VMS ticks), which I don’t think are used in any other Linux API.

Note, however, that you can get a file descriptor <https://manpages.debian.org/bullseye/libdlm-dev/libdlm.3.en.html> for use in event loops, if you’d rather implement your completion notifications that way.