Hi All ,
Just what the subject says , i know this question is been asked so many times and i got some info from google, but not complete. There are many ways of creating a Live USB. but not an installation onto a USB drive.

What i am looking for is ... just to try installing a Linux Operating System on to a USB harddrive and work as if it is installed . Does anyone have an info on that ?

Thanks
Peeths .....

If you install puppy on usb, you have a full distribution.
Idem for most distributions

ex:for ubuntu:

https://wiki.ubuntu.com/LiveUsbPendrivePersistent

If your installer disk recognizes the USB harddisk, then it shouldn't be difficult to instruct the installer to install on that hard drive. It is largely irrelevant to the installer what kind of disk device it is, as long as it can be formatted (maybe not even that).

Starting from the USB hard disk only requires proper BIOS setup.

Tricks with USB booting are only due for old mainboards where the BIOS has no notion of USB devices. There it can be quite tricky ... most of the horror stories on USB disk installs are related to older hardware and older versions of distributions.

If your hardware and distribution does not handle USB disks right away, then your in for a lot of wasted time. The shortcut would be to use an IDE disk for a core installation and mounting the USB disk as a mountpoint (maybe /home or /usr).

Debian