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From: braun@m10ux.UUCP
Newsgroups: comp.os.minix
Subject: Re: use of bios routines in the minix kernal, why not?
Message-ID: <159@m10ux.UUCP>
Date: Fri, 13-Feb-87 13:07:50 EST
Article-I.D.: m10ux.159
Posted: Fri Feb 13 13:07:50 1987
Date-Received: Sun, 15-Feb-87 01:16:53 EST
References: <172@axis.UUCP> <1192@husc6.UUCP> <431@percival.UUCP>, <1216@husc6.UUCP>
Organization: AT&T Bell Labs, Murray Hill, NJ
Lines: 31
Keywords: interupt poll




ddl@harvard writes:

>	Let me try again, real slow.  First intercept INT 9.  When it
>occurs, call the BIOS INT 9 handler.  The BIOS will do all the messy
>key mapping, tell the keyboard that it read the key, send an eoi to
>the interrupt controller, etc.  Now, while STILL AT INTERRUPT TIME, use
>the BIOS poll function to read a key.  If there was something there, hand
>it to the tty driver and do a destructive read to remove it from the BIOS
>fifo.  Sometimes there will be nothing to read (key-up event).  The idea
>is to use the INT 9 event as a cue to read the keyboard.
>	This is not a polled keyboard.  This is an interrupt-driven keyboard.
>This works.  This is how I read the IBM PC keyboard on my multi-tasking
>operating system.  If you want a demonstration then you can either come
>visit me or buy a copy.
>	Not using the BIOS because you think it is ugly is a matter of
>taste.  This is presumably why MINIX does not use it.  Not using the
>BIOS because you think it can't work is a matter of misunderstanding.
>Could we please end this silly discussion?


The keyboard is the easy one.  How is disk I/O done in an interrupt-driven
fashion with the BIOS?


-- 

Doug Braun		AT+T Bell Labs, Murray Hill, NJ
m10ux!braun		210 582-7039