[comp.unix.xenix] Does Xenix use the BIOS for anythin

uhclem@trsvax.UUCP (03/09/90)

<>
R1>BIOS is non-reentrant therefore it is impossible for a multitasking
R1>system to trust it. Therefore you are right and your boss knows nothing.

BIOS also assumes you are not in protected mode.  Protected mode programs
can't use segment registers as scratch registers and other stunts that are
done all the time in the BIOS.  That is why OS/2 keeps having to take
the CPU out of protected mode so it can use the BIOS drivers.
Can you say inefficient?

<My opinion, and not that of my employer who prefers larger and slower
 software to justify bigger and faster systems...>

						
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lws@comm.WANG.COM (Lyle Seaman) (03/23/90)

I may have missed part of this thread, so if this doesn't make sense,
I apologize.  

If Xenix doesn't use the BIOS for anything (because the BIOS doesn't
work w/ protected mode), then by extension, OS/2 and Unix don't use
the BIOS either...

Then howcum' I needed to upgrade my BIOS when I installed an ESDI
controller?

-- 
Lyle                      Wang             lws@comm.wang.com
508 967 2322         Lowell, MA, USA       uunet!comm.wang.com!lws

karl@ddsw1.MCS.COM (Karl Denninger) (03/23/90)

In article <1990Mar22.172812.29265@comm.WANG.COM> lws@comm.WANG.COM (Lyle Seaman) writes:
>
>I may have missed part of this thread, so if this doesn't make sense,
>I apologize.  
>
>If Xenix doesn't use the BIOS for anything (because the BIOS doesn't
>work w/ protected mode), then by extension, OS/2 and Unix don't use
>the BIOS either...
>
>Then howcum' I needed to upgrade my BIOS when I installed an ESDI
>controller?

The BIOS is used in a protected mode operating system only to boot the
machine.

The reason you needed to change your BIOS is that some older BIOSes didn't
correctly execute the initialization code in add-on boards.  This includes
ESDI and other controllers with an on-board BIOS... thus those controllers
would not work correctly.

ESDI, SCSI and most RLL controllers typically have an on-board BIOS that
loads the DPB block for the drives, thus "spoofing" the drive types.  In the
case of the ACB1542 SCSI adapters, it also enables redirection of the disk
I/O routines for use under MSDOS (which is needed to boot from the SCSI
devices).  If the BIOS doesn't execute these routines correctly, you get no
boot up, and thus Unix or Xenix (or OS/2) can't load.

Once the system is up, the BIOS is not used at all; it can't be since it
isn't reentrant.

--
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jpp@tygra.UUCP (John Palmer) (03/23/90)

In article <1990Mar22.172812.29265@comm.WANG.COM> lws@comm.WANG.COM (Lyle Seaman) writes:
}
}I may have missed part of this thread, so if this doesn't make sense,
}I apologize.  
}
}If Xenix doesn't use the BIOS for anything (because the BIOS doesn't
}work w/ protected mode), then by extension, OS/2 and Unix don't use
}the BIOS either...

Another related topic: Has anyone had any luck with installing
COM3 or COM4? I've got an AT clone (386 Modular BIOS by Award)
and am running SCO Xenix 2.3.2 (GT version). I tried to get
COM3 and COM4 working but Xenix wont recognize them even though
it allowed me to specify COM3 and COM4 with "mkdev serial". 
 
The SCO people said that "mkdev serial" lists COM3 and COM4 because
one of the Wyse machines has a BIOS that supports these ports.
He said that there was a way that COM3 and COM4 could become
visible to Xenix but it would require some "hacking" that is
"...not supported by SCO". Question: Has this been done by anyone
out there and what does it involve?
 
Thanks in advance.
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jca@pnet01.cts.com (John C. Archambeau) (03/24/90)

lws@comm.WANG.COM (Lyle Seaman) writes:
>I may have missed part of this thread, so if this doesn't make sense,
>I apologize.  
>
>If Xenix doesn't use the BIOS for anything (because the BIOS doesn't
>work w/ protected mode), then by extension, OS/2 and Unix don't use
>the BIOS either...
>
>Then howcum' I needed to upgrade my BIOS when I installed an ESDI
>controller?

Probably to low level format the hard drive.  
 
     // JCA

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darcy@druid.uucp (D'Arcy J.M. Cain) (03/28/90)

In article <1934@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes:
>lws@comm.WANG.COM (Lyle Seaman) writes:
>>I may have missed part of this thread, so if this doesn't make sense,
>>I apologize.  
>>
>>If Xenix doesn't use the BIOS for anything (because the BIOS doesn't
>>work w/ protected mode), then by extension, OS/2 and Unix don't use
>>the BIOS either...
>>
>>Then howcum' I needed to upgrade my BIOS when I installed an ESDI
>>controller?
>
>Probably to low level format the hard drive.  
> 

More likely to boot the machine.

-- 
D'Arcy J.M. Cain (darcy@druid)     |   Thank goodness we don't get all 
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