Reclaim Hard drive space?

Question

Six months ago, I upgraded the hard drive in my iMac G4 700mhz, from 40 to 160GB. I was running OS 10.2.8, and after formatting (initializing)the new drive, the iMac recognized only 120 of the 160 GB, which I read was a limitation of this iMac model. Recently, I upgraded the OS from 10.2 to 10.4.11. The computer now sees the entire 160GB, but only 120 is available to the iMac's system. Is there a way to reclaim this 40GB without reformatting the hard drive?

Answer 1

You could get a better result from using the newer Disk Utility in the newer
OS X version, since its tools are better and they'd be better suited for setup
and preparation of a hard disk drive for the later OS X system you have.
Any previous system folders created by upgrade installations or archive &
installs could be still on the hard disk drive; and if they are, trash them.
There also may be some hidden folders or other bulk of some kind you
can't see which could be found by using a utility such as 'What Size?'
If there are a pile of other system caches and older parts somehow still
on the hard disk drive, or blocks of occupied space that are not able to
be cleared in a conventional sense of the system being able to overwrite
them once tagged as trash, you may have to consider using the later
boot installer's Disk Utility optional tools to zero-overwrite the drive and
reformat it. And if you still require OS 9 and your computer dual-boots,
then be sure to have OS X install OS9 Drivers. You can run Classic 9
without OS9 Drivers, since the older system folder would not be called
on to boot the computer in that case. That's an option, if you need it.
Third party disk utilities can sometimes help a system; these often
apply in kind to whatever OS X version your computer is running,
so if you have a latest version utility, it may not be suitable for some
older Jaguar, Panther, or perhaps not even Tiger. Compatibility is an
important requirement, otherwise strange issues will likely result.
These third-party utilities are often retail; some are on a boot volume
and others may run partially from some space on the computer HDD.
There may be a problem in how the formatted hard disk drive directory
sees the space or used content in the hard disk drive; so if you have
no utility which can rebuild a directory for the system installed, then to
consider a base or root cure is about it. The booted installer's Disk Utility
and option to overwrite all content, reformat, and reinstall everything
from scratch is one painstakingly longer process. Or clone the existing
system to a prepared externally enclosed hard disk drive, making a
bootable clone so it can work again once it gets cloned back into the Mac;
and then attack the questionable HDD within the computer with Disk Utility.
A good bootable backup clone of the computer's drive content is solid advice.
Getting there is best done when despair is not ruling the moment and when
you can exercise options to be sure the clone is a good one, and the hardware
acquired to make and use one, is the correct type and kind for the job.
{And to partition the computer's hard disk drive so the boot volume in it has
perhaps half of the space should resolve any limits imposed by the hardware
of the computer on readability of an internal hard disk drive. That way, any
portion over the limit could be accessed as though it were another internal HD.
Some OS X systems and some third-party utilities may be able to reformat
without damaging existing content; but don't bet on it. You may find a reformat
to be a cure, but it may also cost you in lost data - unless you make a backup.}
Good luck & happy computing!