What exactly does 'fast file restore' do?

[MSUTech]

We have recently upgraded to Backup Exec 2010 R2 ..... and we had the issue where we had to turn off 'fast file restore' to restore files that were backed up in older versions (the restore process is painfully slow for those older files now)...

Question..... what exactly does 'fast file restore' do???

thanks..

[Ken_Putnam · Accepted solution]

From http://www.symantec.com/business/support/index?page=content&id=TECH43336

When these keys are enabled, Backup Exec (tm) uses fast file access to speed up the process of finding the appropriate spot on the tape that contains the necessary data. In some cases there can be problems accessing the tape using fast file access; disabling these features can work around tape access problems during backup/restore.