3b1 Expansion Box with Rs-232 boards.

Dave Hanna dave at dms3b1.uucp
Fri Feb 15 21:13:08 AEST 1991

In article <143 at beyonet.UUCP> beyo at beyonet.UUCP (Steve Urich) writes:

[Discussion of expansion box full of combo boards, but being able
to access  only tty000-tty006]

>		Does anyone have a patch or know more about this problem?
>I know it can be done, I worked the cmb.rc file and all the shell stuff the
>way I think it supposed to be added, but I think the binary files are set
>for a max of 6 ports and the unix.sym files shows spl0-spl6 something like
>that. I wonder if it is that easy just to edit more to the unix.sym file?

If I remember my internals from when I assisted on a Unisoft port,
spl<n> is the address of a routine that sets the current interrupt
priority level to n, i.e., masks certain level interrupts off.
Since the 68000 has 7 interrupt priority levels (of which the highest
is non-maskable), it would make sense for there to be spl0-spl6.
I think it is just co-incidence, and has nothing whatsoever to do
being able to access only devices tty000-tty006.

I may be mistaken (that was 8 years ago), and I won't be offended if
someone more familiar with internals corrects me.

However, your other supposition, that the binaries are set for a max
of six ports, would not surprise me at all.  That would certainly make
as much sense as allowing a maximum of 2 hard drives and 1 floppy!

>					Steve Urich WB3FTP

Dave Hanna,  Infotouch Systems, Inc. |  "Do or do not -- There is no try"
P.O. Box 584, Bedford, TX 76095      |                        - Yoda
(214) 358-4534   (817) 540-1524      |
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