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Posts Tagged ‘Mac OS X’

invalid BS_jmpBoot error on Mac OS X disc utility

Monday, April 27th, 2009

This error showed up when a friend asked me to fix this 2 TB Western Digital MyBook Studio Edition Drive. The drive can not be mounted, repaired or verified.

invalid BS_jmpBoot error

invalid BS_jmpBoot error

Long story short there is no way to simply fix this error. You can try with TestDisk but I had no luck with it. Don’t jump out of the window just yet since your data is most likely still there. Only the partition table on the drive is damaged and all your data is still in place. Any Data Recovery tool will be able to get your data out of that damaged partition.

If this happend to you consider reading this link

Why RAID is not a good backup solution for private users

Monday, April 27th, 2009

A sad but typical story about why one needs to use backups when dealing with computers

Last Night a friend of mine gave me his almost full 2 TB Western Digital Studio Edition that has a 2 drive RAID 0/1 built in. He told me that he used it with his mac and everything worked just fine. When he connected it to his PC and tried to move some data to the drive it stoped working, which is no surprise since the drive is formated as HSF+ in a RAID 0 configuration. Windows can not handle HFS and somehow managed to serverly damage the pratition table on the drive. After using all tools known to me such as TestDisk, Mac OS X disc utility and Ubuntus partition manager i gave it up as damaged beyond repair. The next step will be to use a data recovery tool to pull out the data, that is still intact on the drive, but all of these programs cost at least 100$. In addition we have to finde 2 Terabytes of free space to recover the data to which also will not come cheap.

Since he used the drive in a RAID 0 mode there was no backup anyway but the very same thing could have happened if it was set up as a RAID 1.

When putting together my home server setup I was considering using one of these RAID drives vs. two stand alone drives and I am glad I chose the two single drives.

Pro RAID

  • the consumer versions like the western digital ones are really easy to set up
  • good protection from hardware failure
  • automatic data restoring
  • only Raid 1 will give you some sort of backup
  • RAID 0 gives you speed gains
  • usually the read feature is a bit more costly than two stand alone drives

Contra RAID

  • no protection from software errors
  • if the RAID it self craps out on you there is very little chance on restoring things
  • if you delete stuff it is gone on both RAID discs instantly
  • if the partition is damaged both drives are affected
  • the physical proximity of these raid drives makes it more likely to die together in case of power surge for example
  • not very flexible – I can always grab one of my two storage drives and go to a friends house to get some data and when I get back home it just syncs to the other drive and everything is fine unless the unlikely case of both drives die at the same time

I do not recommend a single RAID 0,1 or 5 setup as a sufficient backup solution. Backup often, on different devices in different locations!!

time machine back up to remote macs over lan and internet

Sunday, April 5th, 2009

BACK UP OFTEN!!!!

Now that I have my mac mini set up as my home server I also wanted to backup its system drive to preserve all the configuration. I have an Airport extreme basestation that has a 500GB hard drive hooked up to it. I have used it to back up my mac book pro over the air and it worked just fine. When I tried to select it as the backup drive for my mac mini the time machine preference pane would crash every time. So I played arround with it and it appears that time machine is now able to backup to any afp:// file server. It is important that you mount it using the following instructions and not just click on it in the finder. It appears that apple does something differently when using the shares in finder.

Setting up time machine with a remote destination

This is done by pressing command + K in finder and using OS X built in ability to connect to different file servers

connect to server

connect to server

You might get prompted for user name and password. Once connected the afp source shows up in your finder.

afp source

afp source

In my case that is the airport extreme base station called chrillo.Airport with the hard drive. This could also be another mac. Now head over to your time machine preferences and the click the change drive button.

remote time machine backup

remote time machine backup

As you can see it shows up with its Ip address. In my case I used the internal Lan IP

adding Mac OS X like Application Behaviour to your Air Application

Tuesday, March 31st, 2009

In Mac OS X when you close the window of an application the app usually keeps running in the dock. Wheter this is a good thing or not is totally different story, but for apps like mail and ical it certainly is since I want my mail app to keep checking for new mail without the window cluttering up my screen. So what if I want to add such behaviour to an Adobe Air Application.

 	var appIsPersistant:Boolean=false
 	var app=NativeApplication.nativeApplication
 	var window=stage.nativeWindow;

public function set appPersistant(b:Boolean):void{ // adding a simple property to your app b:Boolean whether its stays on or not
 appIsPersistant=b
 	if(b){
 		if(app!=null){
 			app.autoExit=false // preventing the app to exit if all windwows are closed
 			window.addEventListener(Event.CLOSING,hideWindow) // listening for the closing event of the main window
 			app.addEventListener(InvokeEvent.INVOKE,initWindow) // listening for the invoke event if the user clicks on the dock icon
 			app.addEventListener(Event.EXITING,appClose) // listening if the app should be terminated, to prevent the hiding of the window and allow termination
 		}
 	}else{
 		if(app!=null){
 		app.autoExit=true // if app is not persistant the app can close just as usual
 		}
 	}
 }
 public function appClose(e:Event):void{
 	window.removeEventListener(Event.CLOSING,hideWindow) // if the app should terminate with command + Q we have to remove the listener for the Closing event. Otherwise only the window will close but the app will not terminate
 }
 public function hideWindow(e:Event):void{
 	if(window.visible){ // if the window is visible the event behaviour is canceld and the window is hidden
 		e.preventDefault()
 		window.visible=false
 	}
 }
 function initWindow(e:Event=null):void{
 	window.activate() // if the user clicks on the dock icon the window commes back up
 }
 public function get appPersistant():Boolean{
 	return appIsPersistant // just the getter for the appPersistant propery
 }

by adding these few methods your app will exit just fine with command + Q but if you click the close button only the window will close and the app keeps running and comes back up if you click the dock icon

weird file in Mac OS X trash that keeps coming back

Wednesday, December 10th, 2008

I recently found a weird file in my trash that looked like this:

weird file in trash

weird file in trash

It is impossible to delete the file or rename it. secure emptying the trash won’t solve the problem either. if I click on “get info” it disappears. I found the following thread, which provides a good solution to the problem. And don’t worry it is not a virus

http://discussions.apple.com/thread.jspa?messageID=5882792#5882792

Mac OS X disk utility – resource busy error

Friday, October 3rd, 2008
WD mybook 500GB pro edition

WD mybook 500GB pro edition

I noticed that time machine kept preparing for a backup on my western digital mybook 500GB pro edition external harddrive that is connected to an Apple Airport extreme basestation. At first I thought it was a time machine problem but soon I realized that my external harddrive was the source of the problem.

Sympthoms:

  • the disk is not mountable
  • the disk does not show up in finder
  • the airport utility can not access the base station as long as the disk is connected
  • the disk does show up in the disk utility

After screwing with it for a bit I decided to wipe the entire drive in order to fix the problem. Both erasing and repartitioning the disk resulted in an error message saying “resource is busy”.

What did not help:

  • restarting the disk
  • restarting the computer
  • booting from the os x disc and using the disc utility from there will not help either

So I was ready to give up and looked up the warranty information on the western digital website – which is really really good by the way. They had a small windows diagnosis tool for download one should try befor applying for a replacement. So I booted up in windows XP ran the diagnose and it toled me everything was perfectly fine.

The solution to the problem:

just use the standard built in windows XP disk management and wipe the old apple partition and replace it with a new windows NTFS partion( just for now). After this step windows should already be able to see and use the disc under my computer. Now simply reboot to OS X and launch the disk utility, reformat the disk to apples file system and reconnect it the base station.

Note:

Unfortunatly this solution results in complete loss of all your data that was on the drive. But I found no better way.

Mac OS X Leopard – Time Machine & Airdisk after 10.5.3 Update

Wednesday, June 4th, 2008

I run a Airport Extreme basestation with a western digital My Book 500GB USB harddrive attached to it and since 10.5.2 it has been possible to do wireless backup, with a few draw backs. I had to mount the drive manually each time I wanted to perform a back and the back ups took considerably longer than they used to over fire wire but it was working. After I upgraded to 10.5.3 Time Machine kept on telling me

The drive could not be mounted

even though it was already mounted and Time Machine could access it for back ups. I read up on the problem and found some fairly complicated solutions but in fact it is really easy to solve the problem:

Simply go to system preferences and Time Machine and choose select drive and reselect your Airdisk. Not only that Time Machine will continue your old back up but it now also mounts the drive all by it self which which completly automates the Backup process.

I now enjoy Time Capsule like backup without having had to spend a the extra money.