Booting from external HD?

[mikehende]

I used pc mover [laplink] to backup the entire contents of my laptop [which I gave to my cousin 2 years ago] unto an External hard drive, I did this so if something should happen to the laptop she will have everything safe and sound, when I say I backed up the laptop's contents, I mean I created an image of the laptop complete with OS, what I would like to know is, can I connect to that external hard drive and run a pc from it? Meaning, let's say I have a pc with no hard drive, can I use that external just as if it was a hard drive inside the pc?

[Seth]

If the bios supports booting from an external storage device, you shouldn't have a problem. If so, one of two things will happen:

1) XP will simply find the new hardware and install drivers if it has them.

2) XP will attempt to boot, then fail. In this case you would need to run a repair install.

[Tortanick]

Um, can you boot from image files? my instincts say no.

Also if you can't boot from an external HD, you could try booting form a CD (like Knoppix) and hopeing that will detect your external drive.

[mylanta]

I doubt any computer will boot to an external drive but make sure the bios allows the option as that will be the key. If you made an image file though, you could alsways restore the image file from an external drive.

[mikehende]

The reason why I can't count on restoring the image file created is because some thigns did not work when I tried this the last time, to be more specific, I had to re-license a few of my various softwares and don't know why whcih is why I am looking into just running the pc from that external drive.

[dbarrow]

Unless the BIOS has a specific option to choose a USB/1394 device as a boot device, it must load the drivers for it first in order to see it.

Secondly, the HAL of the OS contained in the image will be different than the machine you are attempting to start it from and would crash Windows (any version).
The HAL must load to provide the hardware settings and you need an MBR with volume mount information that tells the machine where to find the files.

Third, it is an image .... one big file ... it would have to be restored to a drive to extract the files.

* I don't know where it went, but a while back, I did post a story with a link to creating a BOOTABLE USB flash drive.
Maybe that can give you some ideas.

[mikehende]

What is the "HAL" of the OS you're referring to please?

[dbarrow]

Hardware Application Layer
This is the System hive of the registry.
It is created when you install Windows on the machine and contains all the hardware settings.

It, by design, protects itself against hardware changes that could be harmful to your machine (and making your OS portable or interchangable with other machines).

Attempting to boot an OS with a HAL from a machine with vastly dissimilar hardware will yield only a BSOD with a hardware protection error.

There are tricks to move an existing install to another machine by forcing the HAL compiler to run but it is a very deep and involved subject I don't think you are quite ready to deal with yet.

And... even if you did accomplish that, it's not like you can then take that version and connect it to yet another machine without going through the same process.

[mikehende]

Appreciate the explanation! Upon purchasing pc mover, I was told that this will only work effectively if used on an identical machine, since I had created an image of the Compaq laptop on the external drive and then copied the drive's contents into my existing Dell pc, this incompatibility I'm sure is what caused some of my software not to work and with your explanation here I have a better understanding why, thanks.

p.s. According to what you wrote here:

"There are tricks to move an existing install to another machine by forcing the HAL compiler to run but it is a very deep and involved subject I don't think you are quite ready to deal with yet."

If I should need to do this in the fututre, I will then look into it, at least it's good to know that there is an option, thanks..

[Seth]

Ok guys, you lost me a bit on this one.

I've gotten XP to boot in a different computer than what it was installed on. However most of the times when I tried it , XP would lock up or I would get a bsod. In that case, if I needed it to boot I would run a repair install.

[dbarrow]

Seth, it all depends on closeness in similarity of the hardware, ie: if you have two machines that are almost identical, same mobo, chipset, etc., XP hardware wizard may just get the HAL compiler to run and it will boot up.

Try that on a machine with a totally different chipset, video card, etc. and it will BSOD with a hardware protection error.

There are various solutions, including Sysprep, that will flag the HAL compiler to run on startup to rebuild the HAL.
This is used all the time in network deploy by large IT departments, but you need to prepare and maintain a 'master' copy of the deploy.

A "repair install" may or may not work.
It will trigger the HAL compiler, but then MS went to great lengths to prevent users from cloning from one machine to another without buying a new version of the OS.

Acronis has a Universal Restore program that will work with the Workstation and enterprise Server versions to accomplish this task by running the HAL compiler as it restores the image.

There are other third party "migration" tools out there.

I have not tested any of these but I am seriously considering it for a new machine I am building.

[mikehende]

I think we may be talking about 2 different issues here Seth? I think the title of this thread is misleading becuase we are dealing with an "image" backup issue here and not simply booting off of an external device.

[Seth]

Thanks for that Doug.

Of the times XP wouldn't boot in this situation, I attempted the repair twice...it booted both times. Although I would never trust it as being stable. If I needed it stable, I would run an over the top install to replace the OS and rewrite the boot information. This of course will rewrite a new registry, so many applications would have to be reinstalled.

[Seth]

I think we may be talking about 2 different issues here Seth? I think the title of this thread is misleading becuase we are dealing with an "image" backup issue here and not simply booting off of an external device.

Maybe. I see two issues here:

1) If the bios will attempt to boot from the external.

2) If the bios boots it, will XP then boot.

Is that right?

[dbarrow]

The image would have to be restored to a drive before it would be visible as an image is either one or a series of compressed archives.

[Seth]

The image would have to be restored to a drive before it would be visible as an image is either one or a series of compressed archives.

Ok, nevermind. I see I misunderstood the question.:)

[mylanta]

Ok guys, you lost me a bit on this one.

I've gotten XP to boot in a different computer than what it was installed on. However most of the times when I tried it , XP would lock up or I would get a bsod. In that case, if I needed it to boot I would run a repair install.

While that is a possibility, it isn't a good one Seth and the pc will never run right if you do that.

[Seth]

While that is a possibility, it isn't a good one Seth and the pc will never run right if you do that.

Agreed. That's why my post #13 stated:

"Of the times XP wouldn't boot in this situation, I attempted the repair twice...it booted both times. Although I would never trust it as being stable. If I needed it stable, I would run an over the top install to replace the OS and rewrite the boot information."