Subject: Re: 3100, console driver/ serial console usage
To: None <port-vax@NetBSD.ORG>
From: Allison J Parent <allisonp@world.std.com>
List: port-vax
Date: 02/13/1998 08:02:25
<???  Does this mean that a MicroVAX II, running Ultrix or VMS, cannot
<operate in text mode on the console after the OS has started?  Seems

It can but the support emulation is extremely limited.  It's there to 
assist diagnostics and boot/console interaction.

<crazy, but in all honesty, I've only seen MicroVAXen running in graphics
<mode (X11) after bootup (my own have no monitors, serial terminals only)

I know it from DECwindows, Ultrix never supported the 3100m76.

<Surely, *if* the ROM contents were mirrored to RAM, which would seem to b
<the way to do it anyway (don't want a sluggish console like Suns have,

What you get is real limited at best.

<What, exactly, do the ROM routines do, anyway?  If one could just access
<the raw bitmap of the display, perhaps one could generate ones own
<characters without using the ROM routines, mirrored or not?  This type
<of access will be needed for the eventual X server anyway...

Besides boot/console they also contain diagnostics and some utilities.  
The terminal emulation is small and it also contains the character maps
used for teminal emullation.  Someone familiar with vax internals could 
code a better text terminal and include that in kernel space along with 
the video bit maps so memory protects are not violated.  I'm sure doing 
in kernel space has problems as it would be fairly large as it would also 
have to include the character maps for at lease a basic font.  There are 
details I may be missing but it's nto trivial as there would be some point 
where the boot console is effectively gone and the system console takes 
over.  That may upset the OS as the the error log goes there and and would 
be "missing" for a period of time while the replacement console takes 
over.

Allison