[Simh] need help with vax780 on linux

[Ian King]

Sorry to top-post, but I'm fighting with Outlook.

I've used the vax780 SIMH emulator, and I've also restored a VAX-11/780(-5), so I wanted to mention a couple of things.  

The VAX-11/780 and /785 boot off an RX01.  TU-58 boot was later.  

Yes, a /780 will boot VMS from a CD, but requires the RX01 to bring up the VAX.  This is one way in which SIMH is significantly different from a real VAX-11.  After the microcode and VMB.EXE are loaded, the VAX deals with device abstractions; our system is set up with a hierarchical storage controller over CI and we have a CDROM installed in one of the shelves.  The standard installation method, i.e. running standalone BACKUP from the CDROM, works just fine.  

I see that the OP solved his problem through known changes to the source - all good.  GCC is a mixed blessing....  -- Ian 
________________________________________
From: simh-bounces at trailing-edge.com [simh-bounces at trailing-edge.com] On Behalf Of Göran Åhling [ahling at eadc.se]
Sent: Sunday, July 24, 2011 12:14 AM
To: simh at trailing-edge.com
Subject: Re: [Simh] need help with vax780 on linux

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Just some thoughts that fly by in reading you post:
>From the mailed .INI-file, the commands set up rq0 as a CD with an attached .ISO-file.
Then you try to boot from this "CD".

Q1: Should the 780-emulator be able to recognize a CD as a device? - In those days the TU58 was "the media" for console works...
Q2: If this booting is proper after all, and the file you have attached to the rq0 is the boot-disc you intend to use, should it really be attached to a "read-only" device like a CD, not to a disc? - I know later systems can boot from a CD, but doesn't that require booting a system image that is tailored to this task - i.e. that doesn't require any dump-files or similar?

(You say that the emulator reads your .DSK properly, but to my eyes does it only read the file vms6_0.iso, ie the CD-immage).

All my best anyhow - every effort to maintain this generation of systems indicates a great spirit!
/Göran