Panther and Disk Warrior 2.1

Discussion in 'Apple' started by Bruce, Nov 4, 2003.

  1. Bruce

    Bruce Guest

    So, I have Disk Warrior 2.1. I recently installed Panther. My iTunes
    is doing some weird things and I am wondering if it is time to run
    Disk Warrior.

    Has Panther changed around the filesystem at all/enough that I should
    worry about not using DW 3.0?

    Are there any other things in DW 3.0 that make it worth upgrading
    (aside from being able to run DW from OS X, which has
    convenience-related advantages)? The DW website is not very clear
    about what 3.0 gives you over and above 2.1.

    Bruce, Nov 4, 2003
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  2. One important thing it gives you is SMART monitoring, so it can tell if
    your hard disks are about to die before they actually do.

    Also, it's a whale of a lot faster than 2.1 at fixing disks.
    Jerry Kindall, Nov 4, 2003
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  3. Bruce

    Scott Rogers Guest

    While I don't know for a fact, I would assume yes, you'd need 3. With
    major upgrades in 10.3, and also, depending on your computer, OS X
    booting only computers wouldn't be able to boot from the 2.1 CD

    I don't know if it's just my machine or not (a G4/500) but I find DW3
    (and Norton 8) to take FOREVER to boot from the CD into OS X
    Scott Rogers, Nov 4, 2003
  4. 2.1 should work fine with Panther disks, as long as your Mac can start
    up from the CD (which contains OS 9). However, rebuilding a disk with
    it will turn off journaling. Since journaling is on by default in
    Panther, you'll want to turn it back on after you run DiskWarrior 2.1.
    Jerry Kindall, Nov 4, 2003
  5. I wouldn't use Norton, but I did notice DW 3 takes about
    a minute or 2 to start up - same as DW 2.x in OS 9.
    George Williams, Nov 4, 2003
  6. Bruce

    matt neuburg Guest

    No, that's not how I read it at all. HFS+ is HFS+; nothing has changed.
    The only question is how you're going to start up DiskWarrior; if you
    were using 2.1 before (presumably starting it up under OS 9 from a
    different partition) then this hasn't changed either. m.
    matt neuburg, Nov 4, 2003
  7. Bruce

    Bruce Guest

    How do I turn off/on Journaling? Is that in NetInfo? And what does
    journaling do?

    I have been using 2.1 now and then under OS 9, which my machine boots.
    It's about the only time I ever use OS 9 (or even classic, for that
    matter). The SMART monitoring thing in DW 3.0 sounds useful though.
    I guess I will repair this stuff now with version 2.1 and order 3.0
    for future use...

    I'm still going to watch this thread though, I'm learning a lot. My
    sense was that HFS+ hadn't changed and that DW 2.1 was probably fine,
    but I don't really know enough about what goes on under the hood of
    Panther to be sure, so that's why I asked.

    Bruce, Nov 5, 2003
  8. In Panther, there's a button in Disk Utility that does it. Journaling
    is a system feature that helps protect the integrity of your disk in
    the event of a severe system crash or power failure. UNIX basically
    caches everything it can for as long as it can, under the (usually
    mostly valid) assumption that the system won't crash, with the result
    that sometimes changes don't get written to disk immediately. Instead,
    the system keeps the changes in RAM, waits for a period of inactivity,
    then does the writes. If you do have a crash (by which I mean the
    whole system goes down unexpectedly), this can leave your disk in a
    rather confused state. Journaling writes changes to a temporary area
    on your disk so as to avoid losing them. Why not just write them to
    where they belong in the first place? Because that would be slow. At
    least with journaling, all that stuff gets put in one area of the disk,
    so your hard drive isn't seeking all over the place. So while
    journaling slows disk writes a little, it doesn't slow them as much as
    making the cache "write-through" would.
    Jerry Kindall, Nov 5, 2003
  9. Bruce

    Mark Day Guest

    It also makes it *much* faster to recover. It is much faster to
    "replay" and transactions still in the journal than it is to examine
    and try to repair every file and directory on the disk (and the bitmap,
    and volume header and ...).
    That's true, but there is a more important reason. The HFS Plus
    structures are complex, and a single change (such as creating a file)
    sometimes requires coordinated writes to several different locations on
    disk. If you're using a disk cache (as most systems do), some writes
    may end up going to disk, while others stay "dirty" in memory. Even if
    you do the writes immediately ("write through"), you could crash after
    some, but not all, of the writes have completed. This would leave your
    disk in an inconsistent state, quite possibly with data loss.

    With the journal, all of the changes are written past the (then
    current) end of the journal. After all of those writes, a single write
    to the journal header changes the pointer to the end of the journal.
    This has the effect of atomically adding all of the writes at once (or
    not at all, if you crash before updating the journal header). After
    all of the changes are safely in the journal (and the header is
    updated), they can be written to their normal locations on disk
    whenever it is convenient to do so.

    When all of the changes eventually get written to their normal
    locations on disk, the journal header is updated to change the pointer
    to the start of the journal (atomically removing all of the changes
    from a single transaction).

    It's this all-or-nothing behavior that gets you the speed and integrity.

    Mark Day, Nov 5, 2003
  10. Bruce

    sam Guest

    How do I turn Journaling OFF if I want to. Once it ON the button is
    dimmed out.

    sam, Nov 5, 2003
  11. Bruce

    Tom Stiller Guest

    Or you can customize the toolbar and add an "off" button.
    Tom Stiller, Nov 5, 2003
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