We have a little joke around the house.  When somebody starts complaining we occationally lean back and mumble – “Tell it to the blog.”  It’s s cruel and unsympathetic pleasure.  So … I’m here to tell it to the blog.

I love my MacBook Air but for the last week we have fallen into a very abusive relationship.

Little over  a week ago the hinge broke.  Mine was purchased a year and half ago and it has a twin bought on the same purchase order.  It’s twin’s hinge broke two weeks before mine.  There were small signs of a problem, a slight looseness in the hinge.  But that’s all and that problem had existed for at least a year.

We had little problem getting Apple to fix either of these machines.  They both had the extended warrenty.  I dropped mine off on a Monday afternoon and got it back on Thursday evening.  The visit to the Apple store was tedious with a hour plus wait followed by a half hour just to fill in the forms on their very slow computers.  I was delighted that they also fixed a slight stickiness that had developed on the left side of the ‘mouse’ button.

Before returning it I let Time Machine finish a backup to my time capsule.  I then mounted the backup and poked around, copying a few essentials to a temporary user account on another Mac in the house.  I then wiped the disk and installed a virgin release of Leopard with an account for the repair guys to use.

While it was in the shop I pulled one or two needed files from the backup.  That was the first time I noticed a problem.  When i went to mount the backup from the Time Capsule via wifi to another laptop it fell into a check the disk image.  I let that run for twelve hours, overnight plus, and finally lost patience.  I hit the skip button on the dialog and while later it mounted the image and I pulled the files I needed.

When I got the repaired machine home had a load of trouble right out of the box.  I plugged in a USB hub and plugged in the Apple Superdrive and the USB-Ethernet dongle.  That didn’t work.  In fact nothing worked on the USB.  Not my headset, not my printer, not with or without the dongle.  But then I noticed that the System Profiler could see these devices come and go as I plugged them in.  So I fire up an insta-theory that the USB firmware was updated at some point and the virgin copy of Leopard doesn’t like that.  So I take the full suite of updates.  That involves a hour plus in the status “running script” but afterward my USB devices are working again.

Well, except.  I now discover that the Apple Superdrive will not work across a USB hub.  You see Apple decided to make this widget non-standard; presumably for some compelling reason involving my aspirations to be a DVD producer.  Since it won’t work over a hub you can’t have both the machine booted from the install DVD and get the advantages of restoring via the Ethernet dongle.  Well maybe I can mount the DVD remotely.  That doesn’t work for me.  I can mount the disk remotely but when I goes to reboot off the disk that doesn’t work.  Much later I puzzle out that you need to be running a special application on the machine that is providing the DVD to do these installs.

You may have noticed that at this point I haven’t gotten to trying to use my backup at all.  But I decide to grab a few more files off the backup so I can get something done in the midst of restoring the machine.  So I try to mount the backup and this time I think I really ought to let that checking run to completion.  So I hook up the Ethernet dongle and let it run.  A few hours later it announces that the backup is broken and suggests I should run Disk Utility to fix it.

So I do.  Hours pass.  It fails.  I try again.  Hours pass.  If fails.

There are numerous discussions on the net of troubles with Time Capsule backups getting corrupted, and there are other discussions of Mac disk images and disk drives getting corrupted.  In fact there are plenty of postings about all file systems getting into bogus states and what to do.  I read lots of these.

Time Machine, at least when backup up to a Time Capsule, writes into a disk image who’s format is known as a sparse bundle.  On the Mac bundles are file system folders full of stuff, and the folder is marked so the UI shows it as a single object.  That’s all sort of irrelevant except that if you want to copy or move a bundle you need to be sure to use a tool that respects those markings and of course you’d want to be sure you move all the soft and hard links without changing them.  The command rsync with the -aE (or -avE) switches is a candidate for doing that.  But when I do it I don’t get the special markings, i.e the extended attributes that the -E switch is intended to get.  And, yes, I did it as root.  Of course you’d rather do your repair attempts on a copy, and better yet if you can get that copy on a fast directly connected drive.  I tried a bit but so far I haven’t puzzled out how to get a working copy of one of these sparse bundles off the Time Capsule.

The advise on how to repair disks or disk images that get corrupted come in stages.  Stage one: run disk util.  Stage two: run fsck_hfs.  Stage two is actually no different than stage one; but it’s hard to be sure so you try it.  Did I mention that each one of these experiments takes hours and you want to do it twice since you cling to the hope each run is actually improving something.  Stage three: run fsck_hfs and ask it to rebuild the catalog.

At this point I have three complains from various checking programs.  Something about threads, something about inode size, and something about corrupted journal.  So stage four: turn off the journaling and try again.  Doesn’t help.

Stage five: dispair.

Stage six: Consider running some other disk repair software.  There are two.  One is called Disk Warrior (~$100 and they mail you the software), and the other is called TechTool Deluxe.  You get a copy of TechTool Deluxe with your extended warranty.  It’s no help since apparently it can’t see the disk unless I can mount the disk, which I can’t.

Stage seven: try to force the sparse bundle to mount without checking.  I fail at my attempts to do this using the unix command line and return to dispair.

Stage eight: try via the Finder.  Doesn’t work on two Macs, but it does work on a third.  That machine says the drive is damaged and that I should backup, erase the drive, etc. immediately.  This makes me snort.

I then copy the latest backup file hierarchy off and heave a huge sigh of relief.

So that’s what I did with most of the last four days of my life.  Still to do is to check all the other sparse bundles on that time capsule, i.e. the backups of other machines in the house.  And then I have to decide what to do so that next time this happens all the details will be different.  I hate computers.