jp48+@andrew.cmu.edu (Jonathan Pace) (04/10/91)
I just erased a disk that was giving me problems and I watched the usually boring description of what was happening. Thing is, system 7 (b4) said it was re-verifying the disk at one point. It took about as much time as the normal verify, which it also did. Is this a feature that it does all the time, or is it just used on disks that are giving screwy verification results? I didn't have time to format other disks to check. Anyone seen/tried the same thing? Jon
amanda@visix.com (Amanda Walker) (04/11/91)
In article <kc0kcZm00WB7I2BUwF@andrew.cmu.edu> jp48+@andrew.cmu.edu (Jonathan Pace) writes: Is this a feature that it does all the time, or is it just used on disks that are giving screwy verification results? I didn't have time to format other disks to check. Anyone seen/tried the same thing? This is a new feature: if the Mac discovers bad blocks, it will mark them as used and re-verify the disk. This will let you use disks with media defects on them, at the cost of a block or two ffor each defect. The "re-verifying format" message signifies that it's doing this second scan. -- Amanda Walker amanda@visix.com Visix Software Inc. ...!uunet!visix!amanda -- X Windows: Live The Nightmare.
rsfinn@CONCERTO.LCS.MIT.EDU (Russell S. Finn) (04/11/91)
In article <kc0kcZm00WB7I2BUwF@andrew.cmu.edu>, jp48+@andrew.cmu.edu (Jonathan Pace) writes: |> |> I just erased a disk that was giving me problems and I watched the usually |> boring description of what was happening. Thing is, system 7 (b4) said it |> was re-verifying the disk at one point. It took about as much time as the |> normal verify, which it also did. |> |> Is this a feature that it does all the time, or is it just used on disks |> that are giving screwy verification results? Congratulations, you've just discovered the new "block-sparing" feature of System 7, described in one of the most recent batch of Tech Notes. Under System 7, the Disk Initialization Package can detect certain errors when formatting disks and mark those sectors so that they are not used. (I believe it only attempts this on floppy-sized disks, under the assumption that good hard disk drivers already do something like this anyway.) When this happens, the Finder displays the "Re-verifying" message. Disclaimer: This is based on a cursory reading of the Tech Note in question, which I no longer have a copy of. Perhaps someone would like to expand on this. -- Russell Finn rsfinn@lcs.mit.edu
torrie@cs.stanford.edu (Evan Torrie) (04/11/91)
rsfinn@CONCERTO.LCS.MIT.EDU (Russell S. Finn) writes: >In article <kc0kcZm00WB7I2BUwF@andrew.cmu.edu>, jp48+@andrew.cmu.edu (Jonathan Pace) writes: >|> >|> I just erased a disk that was giving me problems and I watched the usually >|> boring description of what was happening. Thing is, system 7 (b4) said it >|> was re-verifying the disk at one point. It took about as much time as the >|> normal verify, which it also did. >|> >|> Is this a feature that it does all the time, or is it just used on disks >|> that are giving screwy verification results? >Congratulations, you've just discovered the new "block-sparing" feature >of System 7, described in one of the most recent batch of Tech Notes. This is documented in TN #287: Hey Buddy, Can You Spare A Block? Essentially, it rescans the disk after a verification failure, reading and writing a track at a time to find which one has an error. It removes these sectors from the volume bitmap of available storage. -- ------------------------------------------------------------------------------ Evan Torrie. Stanford University, Class of 199? torrie@cs.stanford.edu Fame, fame, fame... What's it good for? Ab-so-lute-ly nothing
REEKES@applelink.Apple.COM (Jim Reekes) (04/11/91)
In article <kc0kcZm00WB7I2BUwF@andrew.cmu.edu>, jp48+@andrew.cmu.edu (Jonathan Pace) writes: > I just erased a disk that was giving me problems and I watched the usually > boring description of what was happening. Thing is, system 7 (b4) said it > was re-verifying the disk at one point. It took about as much time as the > normal verify, which it also did. > > Is this a feature that it does all the time, or is it just used on disks > that are giving screwy verification results? I didn't have time to format > other disks to check. Anyone seen/tried the same thing? This is answered in Tech Note #287: Hey Buddy, Can You Spare A Block? What's happening is that your disk is bad, but System 7 is attempting to map out the bad sectors. This disk is now usable by HFS. Jim Reekes E.O., Macintosh Toolbox Engineering
ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) (04/12/91)
After all these years, you wonder why Apple bothered... What will this mean for existing versions of disk fixers like Disk First Aid and the Nortilities? Will they see those blocks as in use, but not belonging to any file, and simply put them back on the free chain? Lawrence D'Oliveiro fone: +64-71-562-889 Computer Services Dept fax: +64-71-384-066 University of Waikato electric mail: ldo@waikato.ac.nz Hamilton, New Zealand 37^ 47' 26" S, 175^ 19' 7" E, GMT+12:00 Social success in modern time is much the same as always: mix with people in your own wage-group. -- P K Shaw
REEKES@applelink.apple.com (Jim Reekes) (04/12/91)
In article <1991Apr12.120202.3411@waikato.ac.nz>, ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) writes: > > What will this mean for existing versions of disk fixers like > Disk First Aid and the Nortilities? Will they see those blocks > as in use, but not belonging to any file, and simply put them > back on the free chain? This is why I wrote the Tech Note, and exactly why it was released months before System 7 shipped to users. Some low level utilities may have to be updated. The information in the Tech Note makes is clear to developers what they can expect from the new Disk Init Package. Jim, Mac Toolbox Engineer