Installing Ubuntu from a USB memory stick
Installing from a memory stick is useful if you have a computer without a CD drive (like a netbook), or prefer the convenience of a memory stick. Alternative methods are available, like installing Ubuntu from inside Windows.
Here I'm going to explain on how to install a fully working linux specifically Ubuntu 12.04 LTS on USB Flash drive
Pro's of installing linux in a USB flash drive---
1. Linux is a great OS which can run on a variety of computers without the need of additional drivers unlike windows where you have to install drivers every time you install the OS. So you can say it's a very good OS having very good mobility. ( Now it is challenged by 'windows to go' feature of windows 8 .)
2. Linux requires very less hardware to run.
3. In linux, drivers do not conflict unlike windows so it's easy to use same linux installed on USB flash drive to work with different computer.
4. You can carry your personal and customized OS with you anywhere you want on a USB.
5. Various application can be installed on it like avast antivirus, Gparted etc.... which can rescue a broken system.
Con's of installing linux in a USB Flash drive--
1. As USB flash drives are slow than Hard Disks so the OS will run really slow. Mind it, it will be annoyingly slow.
2. Installing OS on USB may eat your USB Flash drive soon as Flash drives have limited write cycles.
3. Browsing may seem very slow as browsers waits to read cache from filesystem.Now as you have seen the pro's and con's now we will proceed on installing linux.If you have not downloaded ubuntu then download from www.ubuntu.orgAfter downloading burn the downloaded image on CD or DVD and boot from it.
You need at least 4 GB Flash Drive but 8 GB is recommended.
Here is step by step procedure-
1. Boot from live CD in ubuntu.
2. Insert the USB flash drive in USB Port.
3. On desktop double click on icon 'install ubuntu 12.04'
4. Click on continue and it will ask if you want to unmount the flash drive click on yes
5. Choose some thing else when ask to where to install ubuntu.
6. Next you will see your hard disk partitions and flash drive. Click on flash drive partition and then click on change. Change the partition type to ext4 and mount as to '/'. Click on ok to close the dialogue box.
7. In last you will see a drop down menu on where to install the the boot loader. Initially it will be showing sdc,sdd but on drop down you must select sdc1 or sdd1. Failing this step you may render your computer unbootable.
8. Then click on install and linux will be installed on your USB Flash drive.
9. The installation will begin, and should take 10-20 minutes to complete. When it is finished, choose to restart the computer and then remove your memory stick.
Ubuntu should start to load.
10. What if things go wrong?
I can't boot from USB even though I have USB Disk (or similar) as the first option in my boot list.
Sometimes the memory stick will not be recognized when you boot. Leave it plugged in for 30 seconds or so, then restart with it left plugged-in. Or, unplug the memory stick, restart the computer and then plug it in as soon as anything appears on the screen (i.e. as early in the boot process as possible).
Also, some BIOS options could interfere with USB booting. Go into the BIOS and try enabling or disabling options like Fast Boot, USB keyboard support and USB 2.0 support. Finally, make sure you haven't selected a USB-FDD or USB-ZIP boot option.
