Difference between revisions of "Check a Downloaded ISO Image For Errors"

To make the check, you must first download the appropriate ''checksum file'' from the same ''Sourceforge'' website folder as your chosen ISO image. A checksum file will have the same name as the ISO image that it is to be used with; the only difference is that it will end in either '''-sha1.sum''' or '''-sha256.sum'''. For example, the appropriate checksum files for the ''manjaro-xfce-0.8.1-x86_64.iso'' file (64 bit Manjaro release 0.8.1 with the XFCE desktop) would be:  

To make the check, you must first download the appropriate ''checksum file'' from the same ''Sourceforge'' website folder as your chosen ISO image. A checksum file will have the same name as the ISO image that it is to be used with; the only difference is that it will end in either '''-sha1.sum''' or '''-sha256.sum'''. For example, the appropriate checksum files for the ''manjaro-xfce-0.8.1-x86_64.iso'' file (64 bit Manjaro release 0.8.1 with the XFCE desktop) would be:  

* manjaro-xfce-0.8.1-x86_64'''-sha1.sum''', and/or  

* manjaro-xfce-0.8.1-x86_64'''-sha1.sum''', and/or  

The checksum file itself is just a text document that contains a code that should match the code generated by the sha1 or sha256 algorithm. As such, if the code generated from the ISO file matches that contained in the checksum file, then the ISO is fine; otherwise, if the two codes don't match then it means that the ISO file has changed in some way, most likely due to being corrupted. You can think of it like someone using a secret password to identify who they are: if they provide the wrong password, then something is obviously amiss!

The checksum file itself is just a text document that contains a code that should match the code generated by the sha1 or sha256 algorithm. As such, if the code generated from the ISO file matches that contained in the checksum file, then the ISO is fine; otherwise, if the two codes don't match then it means that the ISO file has changed in some way, most likely due to being corrupted. You can think of it like someone using a secret password to identify who they are: if they provide the wrong password, then something is obviously amiss!

To check the integrity of your downloaded file, it will be necessary to first open the downloaded checksum file using a text editor such as ''Gedit''. Depending on whether you intend to use sha1 or sha256, ensure that you have downloaded and opened the appropriate checksum file, that is one ending in *.sha1sum or *.sha256sum respectively) as they will contain different codes. Once the checksum file has been opened and the code is visible, open up your terminal and change to the directory where your downloaded ISO is stored. For example, if your ISO file is located in the default ''Downloads'' folder, you would enter the following command:

To check the integrity of your downloaded file, it will be necessary to first open the downloaded checksum file using a text editor such as ''Gedit''. Depending on whether you intend to use sha1 or sha256, ensure that you have downloaded and opened the appropriate checksum file, that is one ending in *.sha1sum or *.sha256sum respectively) as they will contain different codes. Once the checksum file has been opened and the code is visible, open up your terminal and change to the directory where your downloaded ISO is stored. For example, if your ISO file is located in the default ''Downloads'' folder, you would enter the following command:

  cd Downloads

  cd Downloads

The command to then perform a checksum uses the following syntax:

The command to then perform a checksum uses the following syntax:

  [sha1sum or sha256sum] [ISO Image]

  [sha1sum or sha256sum] [ISO Image]

[[File: sha256.png|thumb|left|375px]]

[[File: sha256.png|thumb|left|375px]]

For example, the following command will use sha256 to generate a code from the 64 bit Manjaro XFCE 0.8.1 ISO. The code generated can then be compared to the code provided by the appropriate sha256 checksum file:

For example, the following command will use sha256 to generate a code from the 64 bit Manjaro XFCE 0.8.1 ISO. The code generated can then be compared to the code provided by the appropriate sha256 checksum file:

  sha256sum  manjaro-xfce-0.8.1-x86_64.iso

  sha256sum  manjaro-xfce-0.8.1-x86_64.iso

As illustrated, in this instance both codes match, thus confirming that the downloaded ISO file is correct. The following command would use sha1 to undertake exactly the same task:

As illustrated, in this instance both codes match, thus confirming that the downloaded ISO file is correct. The following command would use sha1 to undertake exactly the same task:

  sha1sum manjaro-xfce-0.8.1-x86_64.iso

  sha1sum manjaro-xfce-0.8.1-x86_64.iso

When satisfied that both codes match, then it is safe to proceed to either burning the ISO to your chosen installation media, or using it immediately in Virtualbox. If the codes do not match, then it will be necessary to delete the ISO image and download it again.

When satisfied that both codes match, then it is safe to proceed to either burning the ISO to your chosen installation media, or using it immediately in Virtualbox. If the codes do not match, then it will be necessary to delete the ISO image and download it again.

[[File: wincheck.jpg|thumb|left|375px]]

[[File: wincheck.jpg|thumb|left|375px]]

It will be necessary to download and install a checksum utility application. There are many tools which can provide sha1 and sha256 sums.  One such tool is '''[https://github.com/tedsmith/quickhash Quick Hash]'''

It will be necessary to download and install a checksum utility application. There are many tools which can provide sha1 and sha256 sums.  One such tool is '''[https://github.com/tedsmith/quickhash Quick Hash]'''

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* '''[[How-to verify GPG key of official .ISO images]]'''  

* '''[[How-to verify GPG key of official .ISO images]]'''  

* '''[[Download Manjaro]]'''

* '''[[Download Manjaro]]'''

* '''[[Burn an ISO File]]'''

* '''[[Burn an ISO File]]'''