On Mon March 10 2003 14:13, Eric Sproul wrote: >Hi all, >I'm familiar with the general theory of how to "rescue" an AMANDA > tape that's been written with drive compression turned on. > Here's my situation: > >I've completed my first dumpcycle with my current config, and I'm >fairly certain that drive compression has been turned off the > whole time, but I'm not 100% sure. I now have in place a script > that ensures drive compression is off, but it was not put in > place until a number of runs had been done. I want to make sure > all the tapes are uncompressed before I reuse them. > >My question: If I do a dd of some amount of data (like dumping > the first 32K of data as I would if I was saving the label), and > then see (via mt) that the drive's compression is still off, is > it safe to conclude that the tape was written with compression > off? > I believe so. If the drive has a front panel indicator of compression use like mine does, I'd use that for the last word.
>I've read posts that indicate a compressed tape will silently set > drive compression back on, but will that change still be visible > to mt? AFAIK, yes. >BTW, the drive has no DIP switches for setting compression-- That would definitely be unusual... The lawyers have attacked the user stuff in the packaging to the point where it may not be mentioned (I mean "Now why would the *user* need to know that?), and I'd come a lot closer to being able to believe that as opposed to its not having any jumpers or dip switches at all to control its powerup defaults. > it is >completely controlled by software. Also, my system is Linux, so > there are no compression-related device names. I am relying > strictly on mt to manipulate the drive outside of AMANDA, so it's > important that I be able to trust its output. How are you interpreting the mt report so as to define if compression is on or off? I don't recall seeing that in plain english in any mt output report since about RH5.2, and it has changed a bit. Its concise to the point of being obtuse IMO. -- Cheers, Gene AMD [EMAIL PROTECTED] 320M [EMAIL PROTECTED] 512M 99.24% setiathome rank, not too shabby for a WV hillbilly
