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Date:      Mon, 06 Feb 1995 10:26:24 +0100 (MET)
From:      Christoph Kukulies <kuku@gilberto.physik.rwth-aachen.de>
To:        terry@cs.weber.edu (Terry Lambert)
Cc:        freebsd-hackers@freefall.cdrom.com (user alias)
Subject:   Re: Bios basemem (637K) != RTC basemem (640K)
Message-ID:  <199502060926.KAA16197@gilberto.physik.rwth-aachen.de>
In-Reply-To: <9502052155.AA03368@cs.weber.edu> from "Terry Lambert" at Feb 5, 95 02:55:09 pm

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> >[Bios basemem (637K) != RTC basemem (640K)]
> 
> > 
> > Excuse my ignorance, but what does that mean? Do I have to worry?
> 
> It means that either your BIOS starts counting at 0 and something swiped
> 2k of memory, or your BIOS starts counting a 1 and someone swiped 3k of
> memory.  Or your BIOS starts counting at -2 and nothing is swiping any
> memory at all.
> 
> Personally, I have use an AT&T 6386 WGS system that reported 639k all
> the time because it started counting at 0.
> 
> I have also used an HP Vectra system that said 636k because it had
> some wierd disk information that the BIOS put there.
> 
> BSD sees something more than 512 but less than 640, then issues the
> warning, not because the memory isn't there and usable, but because
> it's going to assume you really have 640k, and it wants you to know that
> it is making that assumption.
> 
> Depending on your machine and BIOS, it's probably nothing worse than
> the user configurable IDE drive table.
> 
> One case is that your boot blocks are eating the memory for something;
> typically, something like the OnTrack boot code that loads an INT 13
> redirector to go drive geometry translation for an EIDE drive.
> 
> One of these is the most likely case.
> 
> Absolute total worst case is a boot block virus.  Since BSD doesn't use
> BIOS for I/O, and the kernel isn't typically named a DOS name, this
> isn't a problem unless you run DOS.
> 

> You may want to pull down a virus chacker from wuarchive.wustl.edu, if
> you are absolutely paranoid.  8-).

I checked that, too, using SCAN 2,13e (McAfee)C and it looks clean.

> 

I see this message only when booting the SNAP 950202 floppy.
Booting the hard disk FreeBSD partition does not show the message
(though I still have the old bootloader which looks for 386BSD in the
disklabel - wondered why it did not go away, though, when I labelled the disk
using the 2.x fdisk/disklabel menu).


--Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de
FreeBSD blues 2.1.0-Development FreeBSD 2.1.0-Development #0: Sat Feb  4
16:57:32  1995     kuku@blues:/usr/src/sys/compile/BLUES  i386



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