What is the Difference between “Validate”, “Validate Byte-for-Byte”, and “Validate Disc”?
All TeraByte Unlimited imaging products support a variety of validation methods. This functionality is designed to provide you with as much flexibility as possible, while assuring the best data integrity available.
When considering the differences between the different types of validation, it helps to consider the following depiction of the "flow" of data during a backup:
[source drive] >>> [system memory] >>> [target drive]
Validate
The Validate option (sometimes referred to as a "standard validation") serves primarily to catch errors that occur between the system memory and the target drive. This includes the CPU, mainboard caches, data cables, the IDE/SATA/USB/IEEE 1394 controller, and the target drive itself. This checking is performed on the entire image.
When an error is detected during a standard validation, one of the following error messages will be displayed:
Version 3.00 or later:
ABORT: Data corruption was encountered (error occurred during data processing)
FAIL: Data did not pass validation (data processed, failed validation check)
Version 2.99-00 or earlier:
The image stream is corrupt or Validation failure
These error messages indicates that a problem occurred somewhere between the system memory and the target drive.
Validate Byte-for-Byte
The primary capability of a byte-for-byte validation is to detect errors that occur from the source drive to the system memory. As with a standard validation, a byte-for-byte validation applies to the entire image.
Note that when you use the Validate Byte-for-Byte option, you are actually performing a byte-for-byte validation in addition to a standard validation. Therefore, when using this option, it is possible to receive the aforementioned error messages (those which refer to the standard validation process) or Byte-for-Byte comparison failed error messages. This latter message denotes that an error was detected between the source drive and system memory.
Validate Disc
The Validate Disc option is only available when saving images to optical discs. This type of validation is designed to verify that the data sent to the disc is exactly what is actually written to the disc. This type of validation cannot detect errors that may occur between the source drive and system memory.
The Validate Disc option can be used either alone or in conjunction with the Validate/Validate Byte-for-Byte options.
If the Validate Disc function detects an error, it offers to let you recreate the affected disc. This is beneficial because errors detected by the other types of validation require you to restart the entire imaging process. Please note, however, that if you use the Validate Disc option along with the Validate/Validate Byte-for-Byte options, it is possible for the latter validation method(s) to detect an error that Validate Disc was not able to. In such a case, you would have to start the imaging process over.