What the BIOS does, in this case, isn't relevant, though that should work, I
guess. It's what M$ did in MSD and Windows that matters, since that's
what's getting confused.
Dick
-----Original Message-----
From: Tony Duell <ard_at_p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Sunday, March 21, 1999 12:53 PM
Subject: Re: OT: Re: Security question (sort of)/goodbye
>> As for the serial ports, the UART or maybe ART (also a valid acronymn, I
>
>You know, I've heard of (and used) UARTs, USRTs, USARTs, ACIAs, ACEs
>(Async Communcation Element, I think, which it what Intel called the
>8250). Never ARTs...
>
>> guess, since they're hardly universal any more) these are normally
>> recognized by means of the interrupt they return. If, let's assume, the
>
>Well, the PC/AT simply looks at the Interrupt ID registers of the UARTs at
>$3FA and $2FA. If it gets the right value back, it assumes the UART
>exists. I've just checked the BIOS source listing (section TEST2)
>
>Of course modern BIOSs probably do something totally different, but without
>the source listing it's impossible to be sure.
>
>-tony
>
Received on Sun Mar 21 1999 - 14:25:05 GMT