Date: Tue, 26 May 1998 13:33:42 -0400 (EDT) From: Simon Shapiro <shimon@simon-shapiro.org> To: Mike Smith <mike@smith.net.au> Cc: hackers@FreeBSD.ORG, Eivind Eklund <eivind@yes.no> Subject: Re: Weird behaviour in BootEasy Message-ID: <XFMail.980526133342.shimon@simon-shapiro.org> In-Reply-To: <199805231606.JAA00949@antipodes.cdrom.com>
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On 23-May-98 Mike Smith wrote:
>> I just switched my system to use a different bootdrive (a DPT RAID
>> array, actually) than I had before, and got the following behaviour:
>>
>> On a standard boot, BootEasy won't go to BSD, displaying 'F?' when I
>> select the BSD partiton.
>
> This typically means that the disk geometry is messed up, ie. the
> geometry used when constructing the disk layout is different to the
> geometry that the BIOS is using when BootEasy attempts to load the MBR.
I see that occasionally. It typically goes away when I re-install.
>> However, if I select F5 for booting to
>> another drive (even though I don't have another bootable drive), then
>> reboot, and _then_ press F2 when booteasy appears, it boots and works
>> fine.
>
> Sounds like the DPT is playing games changing its reported geometry
> based on what's on the drive. The fact that F5 appears indicates that
> it's reporting more than one BIOS disk, which suggests that there's
> some ugly stuff going on.
Nope. the DPT will only change its reports if you re-build the array.
BTW, is this a RAID-0 array? If so, it may have old garbage from previous
life (building a RAID-5 array normally wipes the entire array. RAID-1
allows you to copy disk to disk).
>> Let me repeat the exact steps to get it to work:
>> 1. Boot until I reach booteasy
>> 2. Press F5
>> 3. Reboot
>
> What happens when you press F5, before rebooting?
>
>> 4. Continue until I reach booteasy
>> 5. Press F2
>> 6. Boot normally from the FreeBSD bootblocks.
>>
>> If I reboot after this, I again get the F? when it tries to
>> auto-select the BSD partition (or if I press F2 without having pressed
>> F5 first).
>
> The FreeBSD driver probably nukes some state in the DPT that tells it
> that it's changed its mind about the geometry.
Nope. I do no such ugly thing :-) See my comment above about
``inherited'' trash in RAID-0 (and possibly in RAID-1).
>> The BIOS and FreeBSD mostly agrees on disk layout - the BIOS believes
>> there to be 1024 cylinders, not 1954 as below.
>
> Many BIOSsen won't accept > 1024. And many adapters refuse to report >
> 1024 for that reason.
The DPT will report whatever is there, including ``bigger than BIOS'' disks.
>> Any clues? Or should I just re-install BootEasy and see if it goes
>> away? (It seems like such an interesting little problem... :-)
>
> Reinstalling BootEasy won't change anything - it contains no geometry
> state at all. The situation basically results from you having moved
> the disk from one controller with one BIOS translation to another. The
> fact that the DPT learns the disk geometry and lets you boot at all is
> an added bonus; normally you wouldn't be able to do that.
We agree.
Simon
---
Sincerely Yours,
Simon Shapiro Shimon@Simon-Shapiro.ORG
770.265.7340
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