Date: Mon, 3 Jun 1996 21:54:36 -0400 (EDT) From: rhh@ct.picker.com (Randall Hopper) To: julian@ref.tfs.com (JULIAN Elischer) Cc: nate@sri.MT.net, hackers@FreeBSD.org Subject: Re: LBA and Large IDE driver with 2.1R Message-ID: <199606040154.VAA09475@elmer.picker.com> In-Reply-To: <199606040030.RAA12382@ref.tfs.com> from "JULIAN Elischer" at Jun 3, 96 05:30:06 pm
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JULIAN Elischer:
>The slice can be > 512 MB if it is not the BOOTING slice/partition
>>
>> I have FreeBSD 2.1.0-STABLE running fine on a 1.6 Gig disk, and all of
>> the FreeBSD slice lives up on the high 815 meg of the disk. I'm running
>> LBA on an Asus P55TP4XE (dual IDE onboard), and using OS/BS Beta to boot
>> this FreeBSD slice and all the others on this WD31600 as well as my WD31200
>> on wd0. I have had 0 problems -- FreeBSD seems to pick up the translated
>> geometry and life is good.
I don't believe that this describes my system. My root, user, and
swap are all above 512Mb (in the single FreeBSD slice I mentioned). The
only thing below 512Mb that's involved here is my boot loader (OS/BS) which
is on wd0 in cylinder 0. My understanding is that the boot loader just
loads up the boot sector in the FreeBSD slice and executes it, and FreeBSD
then uses the BIOS (the LBA is through my BIOS) to load the kernel.
FreeBSD is somehow picking up and using the translated LBA geometry of my
drive OK, because the kernel loads and the OS runs without a hitch (been
running great for months).
Does the 512MB limit come from the 1024 cylinder limit? If so this
may help explain things. My true cylinder count = 3148. Cylinder count w/
LBA = 787. If the 512MB is just a derived limit and the 1024 cyl is what
counts, this makes sense. FreeBSD uses the BIOS to load the kernel, my LBA
is through my BIOS, so to the BIOS it's loading below cylinder 1024.
Are my suppositions correct here? That is, is 1024 cylinders the real
limit, and 512MB just what it typically equates to without LBA? And
(assuming yes) does FreeBSD fully support a bootable FreeBSD partition
anywhere on an LBA disk given that the remapped cylinder number is < 1024?
(...or am I not even close on this one :-)
Randall Hopper
rhh@ct.picker.com
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