[Info-vax] Tertiary VMB?

[gerry77 at no.spam.mail.com]

On Thu, 15 Jan 2009 15:18:20 -0500, "Paul A. Jacobi"
<Paul.Jacobi at nospam.hp.com> wrote:

> It took me a while, but I finally remember how TERTIARY_VMB evolved!  It was 
> almost 20 years ago...

Wonderful, I was almost sure that sooner or later someone would have
remembered the right details about this! :-)

> TERTIARY_VMB.EXE is exactly the same code as VMB.EXE, except that 
> TERITARY_VMB.EXE is linked with an image header.

TERTIARY_VMB.EXE should contain also something else because it's almost twice
the size of regular VMB.EXE. At a quick inspection it appears to contain also
some FDDI (EXDRIVER, FXDRIVER) and Ethernet (ETDRIVER) drivers! :-)

Maybe this is the same difference that exists between ISL_SVAX and ISL_LVAX.

> MicroVAX systems have a version of VMB in ROM, and MOP load directly to 
> NISCS_LAA.EXE.

Did you mean NISCS_LOAD.EXE (instead of *_LAA), didn't you? 

> Eventually LAN boot was needed on larger system, such as the VAX 8200. 
> These systems do not have VMB in ROM.  LAN boot was implemented such that 
> these systems first request TERTIARY_VMB.EXE, followed by a request for 

Just one last question: how CLUSTER_CONFIG and CLUSTER_CONFIG_LAN procedures
are supposed to distinguish between satellites with and without ROM-based VMB?
When adding a satellite to a cluster, those procedures do not ask anything
about satellite hardware characteristics. Instead, the choice whether to
downline load TERTIARY_VMB or NISCS_LOAD to the satellite seems to be driven
only by the user answer to the question about which MOP service he/she wish to
use (either DECnet/NCP or LANACP/LANCP.) As a matter of facts, DECnet MOP
service seems to always send TERTIARY_VMB while the newer LANACP based one
seems to always send NISCS_LOAD. Any hint on this?

Thanks,
G.