Cant make bootable USB Drive / Ext HD

Question

My hard drive gave out on me the other day, so i went and purchased a new one. However, my optical drive went dead a while back, so my only option to install the OS was via USB or Ext HD. I bought an ext disk drive, but i couldnt get it to run the installer when i booted up (Apple told me that installers wont work on USB ext disk drives) It DID recognize it when the computer was booted up, so i made a CDR of the Snow Leopard CD. I then looked on forums as so how to make it bootable. I cleared an ext, partitioned it, and selected GUID from options.
Now where i run into trouble is here: I went into restore and dragged the cdr to the SOURCE field and the drive to DESTINATION. nothing would happen. i researched and found out that the cdr had to be a dmg. So i converted it. Now when i did it again, i got an error. I went into "scan image for restore" to see if the dmg was the problem, and i get the error: Unable to scan "Mac OS X Install DVD.dmg."(Invalid argument).
Im assuming that i either didnt make the cdr correctly, or i converted it wrong. I still have copied of them both. Any help would be appreciated....

Answer 1

If your optical drive isn't working how did you make a .dmg of it?
Now, what you can do is take the DVD and your external HDD to a computer with a functioning optical drive. Use the Restore option of Disk Utility to clone the DVD to the external HDD:
Clone using Restore Option of Disk Utility
1. Open Disk Utility from the Utilities folder.
2. Select the destination volume from the left side list.
3. Click on the Restore tab in the DU main window.
4.Check the box labeled Erase destination.
5. Select the destination volume from the left side list and drag it to the Destination entry field.
6. Select the source volume from the left side list and drag it to the Source entry field.
7. Double-check you got it right, then click on the Restore button.
Destination means the external drive.
Source means the OS X DVD.
Be sure your external drive has been prepared correctly:
Drive Preparation
1. Open Disk Utility in your Utilities folder.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.
Steps 4-6 are optional but should be used on a drive that has never been formatted before, if the format type is not Mac OS Extended, if the partition scheme has been changed, or if a different operating system (not OS X) has been installed on the drive.
Message was edited by: Kappy