How to create the bootable flash drive in windows, linux, mac

Operating sytem booting from CD / DVD is common these days, there is another ways of booting also there like hard disk and flash drive,

# Flash drive? it is possible?

yes it is possible to boot the operating system by using the flash drives , we will show the tutorials for booting the Ubuntu Linux operating system here

Creating Bootable Flash Drive in Windows

# Inser the USB stick atleast 2 GB

# Download the software  Universal USB Installer

# After downoad Run the file when the download is completed

# If there is any Security Dialogues appears Confirm it by clicking RUN

# READ and confirm the aggrement by clicking “I AGREE”

# Select Ubuntu Desktop Edition from the drop down  list

Note: we are demonstarting by using ubuntu os , the same procedure for other OS also

# Browse and Open the ISO FILE present in the hard disk

# choosing the USB Stic which is F:\   like that

CREATING A BOOTABLE FLASH DRIVE IN MAC

We would encourage Mac users to download Ubuntu Desktop Edition by burning a CD for the time being. But if you would prefer to use a USB, please follow the instructions below.

Note: this procedure requires an .img file that you will be required to create from the .iso file you download.

TIP: Drag and Drop a file from Finder to Terminal to ‘paste’ the full path without typing and risking type errors.

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Download the desired file
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Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight)
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Convert the .iso file to .img using the convert option of hdiutil (e.g., hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso)
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Note: OS X tends to put the .dmg ending on the output file automatically.
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Run diskutil list to get the current list of devices
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Insert your flash media
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Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)
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Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)
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Execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img or ./ubuntu.dmg).
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Using /dev/rdisk instead of /dev/disk may be faster.
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If you see the error dd: Invalid number ’1m’, you are using GNU dd. Use the same command but replace bs=1m with bs=1M.
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If you see the error dd: /dev/diskN: Resource busy, make sure the disk is not in use. Start the ‘Disk Utility.app’ and unmount (don’t eject) the drive.
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Run diskutil eject /dev/diskN and remove your flash media when the command completes
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Restart your Mac and press alt while the Mac is restarting to choose the USB-Stick

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