Booting from hard disk 1 or disk 2

[chris.p]

On the old ATA machines I use (I've got a bunch of 'em and I'm not throwing them away), you can't boot from hard disk 2, even if you load an OS on it. That's because you can only boot from disk 1 on a cable, and they are normally wired:
cable 1 - HD1, HD2
cable 2 - optical drive 1, optical 2

That's usually because the cables needed for that set-up are shorter and the manufacturers too mean. To fix it you have to fit 0.9m cables - well, at least on my big Lian Li alloy cases

Has this changed on SATA disks - can you boot from disk 2? Or do they give you decent cables now?

With Sata drives the boot location information gets stored on the 'first' drive, the actual OS can be on any drive. Most BIOSes I've worked with that support Sata drives allow you to specify the drive boot sequence. So say you had two drives on Sata ports 0 and 1 you could specify the drive on port 1 as the first drive in the boot sequence and boot info would be written there. The OS could of course then be on the drive connected to port 0 if you wanted.

There is one 'gotcha' to look out for.

Say you have XP on drive 1 and install Vista on drive 2 all the Vista BCD info goes to drive 1. If for some reason you have to restore an image of drive 2, Vista will generally not boot. The fix of course is to boot from the Vista DVD and just repair the installation. Remember, though, that if your DVD is an original RTM, and the system has > 2Gb RAM, the process may blue screen many times before the Vista install 'catches.' Obviously if you want to avoid this just take out some RAM, repair the installation, and then put the RAM back again.

Hope that helps.

[chris.p]

Thanks Rik.

So it would maybe work like this:

- with SATA disks, running W2K or XP you can install an OS to disk 1 or 2, and boot from disk1 or 2, on cable 1 or 2

- Vista has problems with a disk 2 location

- Vista can't handle over 2GB of RAM (what's that about??)

Chris,

1. The order of the drives by default is 0 through 5 (each drive has its' own cable) but most BIOSes allow you to change that order to whatever you want, thus determining the drive order as seen by a Windows installation routine. Whichever drive you choose to install on the boot info for the OS gets written to the first drive as this is where the MBR is.

2. If Vista is on drive 2, the Boot Control Database (BCD) will still be on drive 1. The BCD appears to store some sort of either physical placement, CLSID or checksum relating to the Vista install. Therefore, when you restore drive 2 (Vista) from an image this info becomes invalid, hence the need to boot from the installation DVD and perform a repair (it always works)

3. For some bizarre reason, Microsoft assumed when they released Vista that no one would have more than 2Gb of RAM installed, even if installing the 64 bit version. So if your installation media is from early 2006 the Vista install will crash with a BSOD if there is more than 2Gb installed. Note though that once installed Vista will happily support whatever RAM your motherboard supports, subject to the published OS limits.

Vista SP1 overcomes this problem, but slip streaming the SP into an original RTM isn't easy. Basically you have to do a clean install of Vista, on a machine with 2000 or XP installed, to the point where you would normally personalise the install, user ID, machine name and so on. At this point you hit F5 or F6, can't remember which, which takes you into sysprep mode. From this command prompt you install SP1 and once done shutdown the Vista install, boot into your other OS and recreate the installation media.

Simple!??

Thankfully, Windows 7 gets rid of all this hassle, assuming that what actually gets released is similar to the public beta

Regards,

Rik

[chris.p]

Wow.

I'm glad I'm going from XP direct to W7 then. On eSATA or whatever it is by then. If I'm still around of course...

[chris.p]

You should make this a page on the site Rik - it's interesting, many people may not know this stuff, and also it could be that there will be people searching for info about this.