[Ham-Mac] Blue Screen iMac

[Steve Hellyer]

Well as someone who works at Apple. I am not sure I agree with the 
Chris's comments.  (Perhaps Chris has had a rough day?) Actually it's 
called Disk Utility now in OS X with the feature called First Aid.  
It's designed to correct minor problem in directory structure, fixes 
permissions, Enables/Disables journaling, Formats disks, creates 
virtual disk DMG file, creates mirror and stripes and more......

So you see it wasn't intended to be a heavy duty, need a specialist, 
perhaps some surgery utility.  Why the feature is call First Aid.
In many cases it can get someone going again with some basic issues.  
(Like disconnecting a Firewire drive before you unmount it from desktop 
- not a good thing BTW.)

At Apple we have site licensed Disk Warrior and is an excellent utility 
at performing major repairs.  I think it is a very good utility from a 
good company who know HFS and HFS+ , with and without Journaling. The 
UNIX FSCK utility has it own weakness but not the place to go into 
that.

But perhaps it is most important to note that with a UPS 
(Uninterruptible power supply) and a USB connection this all could have 
been avoided.  Remember most hard drives have about 8 MB of cache on 
them these days. The system does some caching as well.  If you lose 
power you have lost at least 8 MB of some data. Worse the heads on the 
drive can bang into the platter and you can lose everything!  Once 
power goes out all bets are off and you are at the mercy of the law of 
physics and random chance especially where 7200 RPM drive are 
concerned.

Mac OS X supports most UPS's  through USB connection directly.  I run a 
small one from APC (less than $100 CDN) which when there is only about 
5 min. worth of power left automatically perform a proper shutdown.  
Saving you from this all of this and perhaps worse!

I think if you have one of these UPS's and run current Mac OS X with 
HFS journalling on you may never need such a such a Emergency tool as 
Disk Warrior.

Preventive medicine is much better than all others.

Jerry this email is not to pick on your situation or make light of it.  
Over many years I have been in your situation and worse. Just wanted to 
point out Apple is focusing trying to put thing in place the help 
prevent this from happening as much as one can.

If you still have problem you can always try calling Apple Helpline 
1-800-SOS-APPL.

Hope this email of some help.

73
Steve
VA3SPH

On 3-Dec-04, at 5:16 PM, Chris Smolinski wrote:

>>
>> 	I will resoundingly second this.   I have two or three times so
>> far rescued disks using DW that Apple Disk First Aid wouldn't touch 
>> and
>> in the process not lost any files except a few temporary ones open at
>> the time of the crash.
>>
>
> fsck should be able to fix any volumes under OSX, although it might 
> require a little reading up on the usage, and it does require some 
> interaction/knowledge on the part of the user.
>
> I've never used DW, but I can say that Apple's Disk First Aid is 
> perhaps one of the most useless utilities Apple has ever shipped. It's 
> rarely been able to fix any type of disk problems, even dating back to 
> the classic days.
>
>
> --