Adding external back-up hard drive?

Question

Im relatively new to iMac and still finding my way around it. Likewise, I've looked around the discussion forum but unable to find the key words to my problem but Im sure it has been discussed before. If so I apologise.
I have a Toshiba External (Back Up) Hard Drive which was a back up to my Windows Based PC and therefore has numerous images on there. Anyway, how do I get this set up on my iMac without loosing any of the info on the Back Up hard drive, also wish to use this as a back up for images from my IMac too. Do I also need to reconfig my images as I used Adobe photoshop in the first instance or will it change automatically to iPhoto?
Any info / assistance will appreciated but please keep advise / explanations simple as I sometimes tend to throw dummy out of the pram when I get frustrated. Just like now!! LOL.

Answer 1

Here's the problem, in my attempt to explain it a little more clearly. There are a number of different ways data can be written to a drive, called "partition schemes"... think of them like languages used when printing a book. Like languages, some systems cannot understand some drive partition schemes. Unlike languages in a book, however, a system may be able to read a partition scheme, but be unable to write to it.
In the case of a Mac, it can read/write APM (Apple Partition Map), GUID and FAT (an old MS-DOS scheme) drives. However, it can only read NTFS drives, and NTFS is what Windows typically uses. Most likely, this drive of yours is NTFS. (You can tell for sure by selecting the drive in Disk Utility - not the volume, with the familiar name, the drive, right above it with a name that includes the size - and looking in the info at the bottom of the DU window.)
So, your Mac can't write to that drive at all, even though it can read it. Although there is software that can give your Mac the ability to write to that drive, it will never work with the Mac's built-in backup software (Time Machine), which requires that the backup drive be GUID. That may not be an issue, as TM is far from the only backup software out there. Something like [Carbon Copy Cloner|http://www.bombich.com> or SuperDuper may be able to work with that drive, given software that lets you write to NTFS.
Whether or not you ultimately end up making this drive work for backup of your Mac, note that it is important that you have multiple backups of any data you don't want to lose. So, those images need to be stored in at least one other place (preferably two or more). That given, you may want to repartition that drive with a more Mac-friendly scheme after you've gotten some backups of those images made. (Assuming, of course, that you're no longer working with Windows... if that's not the case, keeping a Windows backup on that drive would probably be wise.)
See my [Mac Backup Guide|http://www.reedcorner.net/guides/backups> for more on backup strategies in general.