*BSD News Article 45562


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From: kelly@junco.fsl.noaa.gov (Sean Kelly)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: FreeBSD: serial port devices, 64 head disk drives
Date: 19 Jun 1995 04:11:35 GMT
Organization: Forecast Systems Laboratory
Lines: 74
Message-ID: <3s2tdn$aqj@CUBoulder.Colorado.EDU>
References: <3s2ehj$l8a@stork.qut.edu.au>
NNTP-Posting-Host: junco.fsl.noaa.gov

In article <3s2ehj$l8a@stork.qut.edu.au>,  <williamsr@redash.qut.edu.au> wrote:
>I have just installed FreeBSD 2.0, and I have has some problems getting
>a couple of parts working:
>
>  + I don't seem to have a device for any serial ports, so I can't get the
>    mouse working, so I can't get X working...  I have the mouse on COM2:,
>    a 16550 based serial port at the standard address

Type

	dmesg | grep sio1

If you see output similar to

	sio1 at 0x2f8-0x2ff irq 3 on isa
	sio1: type 16550A

then FreeBSD is correctly finding COM2:.  If not, reconfig your kernel
to find the device correctly.

Then, do this

	cd /dev
	./MAKEDEV tty01

(If you're running 2.0.5, use ttyd1 instead of tty01.)

Use /dev/tty01 in your XF86Config file in the "Pointer" section as the
mouse device.

>  + I am using a 1GB enhanced IDE hard disk.  The disk runs as 525 cylinders
>    with 64 heads under dos, but FreeBSD doesn't support more than 16 heads
>    so it has to run as 2100 cylinders with 16 heads.

Actually, FreeBSD is using the real geometry of the disk, and DOS is
using the fake LBA-translated geometry.  Think how much taller the
drive case would be if it really had 64 heads in there.

>    FreeBSD can't boot past 1024 cylinders,

More correct: no BIOS-booted operating system can boot past 1024
cylinders.

>    and DOS just plain won't read past it, so basically I have to
>    re-write the partition table to a different geometry every time I
>    want to switch between DOS and FreeBSD.  Is there any way around
>    this?

DOS will work with the actual geometry.  I've got a 2100 cylinder/16
head drive in one system shared between DOS and FreeBSD.  It depends
on how much space you want DOS and FreeBSD to have.  DOS needs all of
C: to be within the first 1024 cylinders to boot.  FreeBSD needs all
of the root partition (/) to be within the first 1024 cylinders.

So, here's my advice:

*  First, turn off that damn LBA translation.  This is probably an
   option on your CMOS configuration screen somewhere.

*  Allocate about 150 to 300 megabytes to DOS and/or OS/2, depending
   on your needs; put it *first* on the disk.

*  Allocate the *rest* of the disk to FreeBSD, and make the root
   partition ends before cylinder 1024.  This is easy since the root
   partition won't need to be larger than about 20 megabytes, again,
   depending on your needs.

-- 
Sean Kelly
NOAA Forecast Systems Lab, Boulder Colorado USA

I think a good gift for the president would be a chocolate
revolver. And since he's so busy, you'd probably have to run up to him
and hand it to him.  -- Jack Handey