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Date: Wed, 13 Mar 1996 13:52:58 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199603130252.NAA22009@godzilla.zeta.org.au>
To: freebsd-current@freebsd.org, j@uriah.heep.sax.de
Subject: Re: COMCONSOLE: a patch and a problem
Sender: owner-current@freebsd.org
X-Loop: FreeBSD.org
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>>   I'll also take a look at syscons and see why it should
>> be different.

>syscons uses a different tty structure for the console than for VT1.
                                                                   0


>Most people would hesitate if you always write back the boot block,
>just to store a single bit in it.  Well, van Gilluwe reports bit 2 of
>the so-called ``equipment byte'' in the CMOS (offset 0x14) as
>`unused'.  Perhaps we could use it to store the serial console flag
>there? :)

The Interrupt List says:

  14h - Equipment Byte
    ...
    Bit 3 Display ENabled ...
    Bit 2 Keyboard ENabled ...
    ...
  14h - (AMSTRAD)    BYTE user RAM checksum

I have used the keyboard security lock bit.  This is easy to test for
(((inb(0x64) & 0x10) == 0) means locked) but has other problems (my
Award BIOS hangs if the keyboard is locked and the BIOS "Halt on
keyboard error" is disabled; I have to disable "Halt on disk error").
Some systems don't have keyboard security locks.

Bruce