[Info-vax] compile for VAX 8650 system

[Simon Clubley]

On 2016-06-08, Stanley F. Quayle <stanley.f.quayle at gmail.com> wrote:
> If you are building a system from "scratch", you will need to find
> the VAXeln tool kit, VMS, etc. etc. But if you image all the disks
> from the existing system to an emulator, your existing disks come over
> with all that stuff ready to go.
>

The problem with that is that the OP said in another post:

|The OS running on the current system is VAXELN, do you think OpenVMS will
|still work?

IOW, he believes the VAX 8650 is the VAXELN target system, not the
VAXELN development system so imaging that system would just get you
the VAXELN based application binary. However, offset against that is
John's point about the VAX 8650 not being a supported VAXELN target
according to the SPD.

BTW, for anyone reading this who is not familiar with VAXELN, you should
be aware that VAXELN isn't some application which is run in production
use under VMS, VAXELN is an operating system in it's own right.

What you do is use the VAXELN toolkit under VMS to compile and link an
VAXELN application image (which includes the VAXELN kernel) and then
you move that image over to your target system somehow and boot the
image on your target system.

IOW, there are _two_ systems potentially in use here: (1) the development
system running VMS and the VAXELN development tools and (2) the target
system which runs the generated VAXELN image.

These days, unless you are using a RTOS with self hosted tools, you do
(1) on a machine running Linux (or Windows) and then you transfer your
newly built RTOS image over to a different system to run it.

However, given the price of the hardware in decades past, it's not
beyond the bounds of possibility that the VAX 8650 in question is
a dual boot system with the VAXELN image on one disk and the development
VMS system on another disk.

IOW, the developer at the time may have booted VMS off one disk, done
any needed software development and then shutdown VMS and booted VAXELN
on the same system. Given the relative prices of hardware and developer's
time that would be a hopelessly inefficient way to develop embedded
software these days but several decades ago the tradeoffs might have
been very different.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
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