[Info-vax] VMS on Raspberry Pi 5

[Jake Hamby (Solid State Jake)]

On Monday, November 13, 2023 at 3:40:19 PM UTC-8, Martin Gregorie wrote:
> On Mon, 13 Nov 2023 17:44:15 +0000, Pancho wrote: 
> 
> > Looking back on it now. I think the strangest thing about VMS was the 
> > Manual Set.
> I was part of one, fairly large, project on VAX/VMS. I thought the oddest 
> part of it was the way the usual collection of programmer's utilities were 
> implemented as a handful of multi-function development tools, i.e. one 
> program that handled all source file management tasks, another to take 
> care of all comms tasks, etc. I've never met any other OS that was 
> structured that way. 

I think that's one of the amusing quirks of VMS. It has a command interpreter that's almost like a text adventure game parser in its flexibility. There's a command definition utility to tell DCL the mapping from commands to the actual .EXE that handles it, so sometimes it's not at all obvious what program(s) implement which features.

I wouldn't say the programmer's utilities are any more monolithic under VMS than UNIX, but there can be a dozen or so different functions provided by a common verb like "SET", "SHOW", or "ANALYZE", with DCL using the command definition tables to activate the right program, and that's very unusual.

> Several years later I did another project on DEC Alpha Servers running 
> Tru64 UNIX, which I preferred to VMS, being a UNIX fanatic. Tru64 UNIXwas 
> pretty much a straight-forward port of UNIX System V functions and 
> programing tools onto a MACH-based kernel. This was amazingly fast for the 
> era and fairly bullet-proof.

Tru64 UNIX was quite well-regarded. Tru64, and OpenVMS Alpha, both had CPU hardware counter-based performance profiling just like Linux's "perf", but years earlier (Linux perf was first released in 2009).

Here's a paper from April 2001 describing how "DCPI/ProfileMe" let you drill down to see how your code was performing at the instruction level. https://www.mikerohard.de/alphalinuxperformance3.html

And here's a paper from 2003 describing DCPI on OpenVMS. https://www.zx.net.nz/mirror/h71000.www7.hp.com/openvms/journal/v2/articles/dcpi.pdf

Regards,
Jake Hamby