The difference is that a "pass" is a single wiping process applied to the entire HD, beginning to end. Thus, a predetermined wiping alogorithm may have one or several passes (e.g. DoD has either 3 or 7; Gutmann has 35). Which means that each "pass" represents a single wipe of the HD.
A "round" is how many times the predetermined passes are repeated. Thus, if you select the Gutmann wiping algorithm and set the rounds option to 2, it would repeat the process twice, thus doing a total of 70 passes.
1 - I saw something "strange" while wiping a single file with Eraser and the Gutmann method.
For example, I have wiped a 50MB avi file, and when I take a look to the wiping process window it repeats the 35 passes 4 times (rounds)!
But if use the wiping tool of Blowfish Advanced CS with the Gutmann method, it wipes always with 35 passes for 1 time (round).
So, do the default round options of Gutmann method in Eraser are set to 4 or higher?
Where I can set this opition?
I didn't find where to change the rounds in Eraser (I can set only the number of passes in PRNG method).
2 - Do DBAN can set the rounds?
I would like to nuke my 80GB HD but, as i read here, 8 rounds/1 passes of PRNG method is a good wipe.
So, it would be the same if I set 8 passes/1 round..
Where is the difference??
Couldn't tell you in regards to Eraser. Perhaps it was erasing the alternate data stream...don't know. You might want to ask this question in the Eraser support forum.
I also have Blowfish Advanced CS. There is no option to set how many times it repeats the wipe process.
In regards to DBAN, if you choose the PRNG stream wipe option and set the passes to 8 and the rounds to 1, it'll wipe the HD 8 times. If you set the rounds to 2 instead, it'll wipe the HD 16 times. If you set it to 3 rounds, it'll wipe the HD 32 times...
Changing the rounds in regards to the use of PRNG stream wipe algorithm is pretty much meaningless, since each pass is random. Just change the number of passes to suit your needs. If you choose to do Gutmann and the rounds are set at 2, then DBAN will repeat the Gutmann wipe twice for a total of 70 passes.