Install an operating system on an external disk when laptop is running?

At least in OS X you can make a bootable partition for the installer and from there you can plug in the drive and install from that. It only takes about 10 minutes if you know what you are doing.

Ummmm…. I’m not so sure….. but keep listening, well seeing other people’s answers good luck!

Yeah I know you can install to a USB hard drive like you regularly would be this would be nice, hopefully someone knows how to.

Have you searched on portable OSs?

Perhaps unetbootin is what you need.

Most OS’s build themselves around the hardware during the installation process, but there are a few Linux distros that can be installed by simply copying the disk image to the drive.

Chromium OS (built by Hexxeh)
Slax
Ubuntu “Live” install
DSL
Puppy Linux

For any other operating system, you may be able to install to a VMware virtual image and somehow copy it to a physical drive. However, your CPU and RAM will be fully consumed during most of the installation process, so your computer will be barely usable anyway.

@Vortico Yeah, thats probably the only way ant not really worth it ebcause I have a few shells of computers that I could use.

You can do it with a LiveUSB with persistence enabled. If you have a small USB3.0 or eSATA drive, you wouldn’t notice a performance hit either.

Use Linux Live USB Creator; it should do the job.

Many OS installers I’ve seen ask what partition (and volume!) you want to install to, and is doesn’t have to be one in an internal bay. or even connected via IDE/SATA.

Can someone tell me why exactly this would be desirable? I’ve generally used external HD’s as drag-and-drop storage units. I have a few that I’ve used with multiple OS’s without any issue. What am I missing out on?

@dappled_leaves Sometimes you want/need to boot a system with an OS other than what is on there. Some hardware faults cannot be corrected if you boot from the installed hard drive, some tests cannot be run, sometimes the installed OS is borked, and sometimes there just isn’t an installed OS. And then there are times where you want to borrow a computer but not use the installed OS or software; yuo wan tto make it your system, but only temporarily.

Some people prefer special boot CDs in cases like those while some prefer USB Flash drives, but some like doing it from hard drives.

“And then there are times where you want to borrow a computer but not use the installed OS or software; yuo wan tto make it your system, but only temporarily.” – good point. I could see that it would be valuable if you have problems with your OS, but couldn’t figure out why it would be useful otherwise. Thanks.

@jerv is right. The main reason is so that I could keep an eye on the isntallation. I personally like bootable CD’s though.