Partitioning hard drive with disk utility

I remember back in the day of the PC there was a program called i think it was Partition Magic. Great program that would let you do just about anything you wanted to your drives without having to go through all the work of moving, backing up, reinstalling your programs.

I'm just getting started with El Capitan and am wondering if it will let me do basically the same thing using disk utility. I've read a couple of things that seem to say it will. Has anyone done it yet with good results. I have a 1 T disk drive that at the moment only has a few programs and the OS X boot install. What i would like to do is partition the drive into 4 partitions using one partition for the OS X boot and using the other 3 for different things like my music library, documents etc. Can disk utility do this without having to format and start from scratch ?

Your answer is no. You cannot partition a HD without effectively erasing it. The reason is fairly simple when you think about it. Imagine the Disk is a pie. The information you have on the pie is spread around but we can’t see exactly where. Now you want to cut the pie into 4 equal segments. That would leave some parts of the files on segment one, some on segment 2 etc etc but now the parts can no longer communicate with each other.
So the way to do this is to save/copy the files somewhere else (your computer HD if you have space), partition the external HD (format Mac OSX Extended (journaled)
and copy the files back.

Thank you for your response, I was afraid that would turn out to be the case. I had seen a couple of messages that said it could be done on the later versions of OS X, but wanted to find out if anyone had actually done it before going for it. Your statement about "cannot do so without effectively erasing it" is not quite true, i used to do it on my old windows system with Partition Magic, but evidently OS X hasn't seen fit to bring that little gift to the Mac.

Although after i wrote the original post i did give it a try on a small USB external drive, and i will be darned if it didn't look like it actually worked. I ended up with 3 partitions instead of one and all the files that were on the original were still there. Of course like you say they may have been spread all over the drive and not usable, that is why i asked if anyone had done so with success. Rats, now i will have to spend hours doing it the old fashioned way...

Although after i wrote the original post i did give it a try on a small USB external drive, and i will be darned if it didn't look like it actually worked. I ended up with 3 partitions instead of one and all the files that were on the original were still there. Of course like you say they may have been spread all over the drive and not usable, that is why i asked if anyone had done so with success. Rats, now i will have to spend hours doing it the old fashioned way...

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I still have my copy of Partition Magic laying around somewhere. Actually, there is a way to partition large drives similar to PM; the program is called: iPartition, however, it's $49.95 to buy a license.

As chscag says, there are or were several partitioning apps around, but I wouldn't be surprised if El Capitan doesn't kill them or prevent them from working, besides the price being a bit discouraging. Or reliability …????

But Disk Utility can still do a lot and can give you several options without nuking and starting over.

PS: ALWAYS advisable to have a checked working backup.

James said:

i used to do it on my old windows system with Partition Magic, but evidently OS X hasn't seen fit to bring that little gift to the Mac.

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How is this Apple's fault, exactly? Do they make Partition Magic for Windows?

No, they don't. So it would be more accurate to say that the makers of Partition Magic haven't opted to make an OS X product.

No, they don't. So it would be more accurate to say that the makers of Partition Magic haven't opted to make an OS X product.

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Actually Partition Magic was bought out years ago by Symantec (owners of Norton products). I already suggested to the OP a OS X product which does the same thing. Yes, it's a bit costly to purchase but it works well since it's developed for OS X and yes, it's compatible with El Capitan.

chas_m said:

How is this Apple's fault, exactly? Do they make Partition Magic for Windows?

No, they don't. So it would be more accurate to say that the makers of Partition Magic haven't opted to make an OS X product.

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And i did not say it was Apples fault i said "evidently OS X hasn't seen fit to bring that little gift to the mac", that is unless Disk utility can do it. I see there are one or two 3rd party utilities like iPartition, but i also see a lot of people giving them the thumbs down for either not working properly or crashing their drives.

I still am not all that sure that Disk Utility can not do what i am looking to do. The USB drive i tried a test run on seems to be working fine after running it through Disk Utility. I went from 1 partition to 3 partitions with the data that was on the drive still showing up after all the work was done. I have also added data to the 2 new partitions and both seem to work properly, but unless i get some feedback that it does indeed work there is no way i am gona risk a 1 T boot disk using it, i will just have to take the time and do the work the old way and format and re-install after i get the partitions i want.

And your right about the makers of Partition Magic, they probably never will make an OS X version, to bad cause i would buy it in a second, it was that good a program.

chas_m said:

How is this Apple's fault, exactly? Do they make Partition Magic for Windows?

No, they don't. So it would be more accurate to say that the makers of Partition Magic haven't opted to make an OS X product.

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Ahem… I think they did that some years ago:
http://www.partitionmagicmac.com

But it would be nice at times if Disk Utility could do a bit more than it does for active partitioning.

@pm-r:

It's not the same company as the original Partition Magic. These are the same guys who make and sell the "Stellar" products. Look them up yourself.

Disk Utility will retain information when you resize the drive to multiple partitions just like Windows OS does now. I remember Partition Magic for Windows. It was a great product. Just be aware that Disk Utility resizes available space rather then total free space.