Using dotISO Files

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Revision as of 01:35, 19 August 2012 by Rpeters (talk | contribs)
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Files having the extension *.ISO may be new to some readers. These files are essentially an image of a CD, DVD (or BlueRay ?) optical media and usually images of bootable media. dotISO files may be downloaded, saved, copied to other disks/volumes/folders etc, exactly like any other file. However, they require special processing to achieve their usual purpose of producing a bootable media

  • originally dotISO were intended for CD/DVD media
  • the same files may now be made into bootable USB/SD media
    • this requires a different program to write the media

The bootable media are typically used for one of:

  • a "live" demonstration system - often based on Linux
  • running software for backing up systems and/or data
  • installing operating systems
  • "rescue" systems
those not familiar with operating systems need to execise caution with the last two

Burning Bootable CD/DVD

  1. this will be the simpest and most reliable approach for beginners
    • virtually any computer now in use can boot CD/DVD
    • most OS have suitable software for burning CD/DVD
  2. a common mistake made by novices is to use their favourite burner software to copy a *.ISO file to a blank CD/DVD - incorrect as explained at
Correct procedure is to use a special option in the burner software to "burn CD ISO image" or "burn DVD ISO image". Popular burner software Nero and Deepburner have this option. If in doubt, get the product and install that. It makes the operation foolproof, because its only function is to burn ISO images to CD/DVD.

In Windows 7, locate the ISO file in Windows Explorer and right-click it. You will get various options - click on 'Open with' then choose 'Windows Disc Image Burner' to produce a bootable CD/DVD. To be prudent, tick the 'Verify disc after burning' box.

dotISO images that are smaller than 700 MB may be burnt to DVD media (most burner software will cope with this). Doing so is likely to result in the media reading somewhat faster than would be the case with CD media and this can be advantageous for the uses described above.

Writing Bootable USB/SD

Writing ISO Files

  1. this method is suitable for beginners
    • it shoulc suceed with all dotISO files, provided that those are bootable images
  2. obtain and install a suitable program
    • unetbootin is one of the better known
  3. ensure that the USB/SD media to be used is formatted FAT 32
  4. as a precaution, disconnect all other USB devices from the computer
    • including scanners, mobile broadband sticks, modems etc
  5. launch unetbootin
    • locate the downloaded dotISO file on hard disk
    • select the USB/SD media to be written
    • click OK

Writing ISOhybrid Files

  1. this task is for intermediate/advanced users
  2. some dotISO files are now being provided as "ISOhybrids"
    • these may be written to CD/DVD/USB/SD media, as above
    • but require this alternative procedure to achive their main advamtage of typically booting much faster
      • because most OS use conservative settings to boot USB/SD devices, in order to cope with older/buggy BIOS
  3. dotISO of unknown type may safely be converted to hybridISO via the program "isohybrid"
  4. ensure that the USB/SD media to be used is formatted FAT 32
  5. as a precaution, disconnect all other USB devices from the computer
    • including scanners, mobile broadband sticks, modems etc
  6. launch a program for writing images of storage media eg
    • in Windows use "rawwrite"
    • in other OS use "dd"
  7. more detailed instructions are at:

execise great caution with the above programs - an error in selecting the USB/SD device could result in hard disk partition being overwritten

Booting from Media

Booting from CD/DVD/USB/SD drives is disabled, by default, on many computers as a precaution against malware

  1. on modern PC it can be temporarily selected by pressing a key (usually F11, but sometimes F12) at boot
    • Then select the relevant drive from the menu presented.
      • "CDROM" for internal optical drive
      • "USB CDROM" for external optical drive
      • "USB CDROM" for USB drive written from standard dotISO
      • "USB HDD" for USB drive written from hybrid dotISO
      • "SD" for internal SD drive
  2. on modern PC it can be enabled persistently via CMOS setup and setting the above devices to ENABLED in the boot sequence

--Rpeters 11:35, 19 August 2012 (EST) --