What is the difference between Bytes Written and Bytes Read?

[Echo2976]

I am just learning Backup Exec 9.0 and I have not been able to find an answer to this yet. In the Statistics of Slot Properties under the Drives tab it say Bytes Written and Bytes Read. These numbers do not match up. I am assuming this is due to compression.

For Example:

Slot 1 --
Bytes Written : 7056.1 MB
Bytes Read: 20018.1MB

Thank you

 

[jebiga]

Bytes Written - Number of bytes that have been written by this device.

Bytes Read - Number of bytes that have been read by this device.

 

[Echo2976]

No I understand the denotative meaning of the words 'written' and 'read'. And as this information is gathered from the statisitics of the drive I figured it was refering to 'this device'. What I don't understand is why these numbers vary and what the significance of them is. If the device is reading from the same tape as it is writing to (which it is) then shouldn't the size written be equal to the size read?

 

[justin2000]

Maybe because you have read more ie. restored more, than written more ie. backed up to this tape.

They won't ever be equal - if they are it is just plain coincidence.

 

[Tomadler]

Bytes written is obvious. That's how many bytes have been written onto the tape during the backup process.
Bytes read, however, means that be is reading back the structure and catalog of the tape to find out if data is written correctly and how much space is left on the tape.

 

[Echo2976]

Thank you, that makes sense to me. I appreciate everyone's help.