securely erase harddrive on iMac Power PC G4, OS 10.4.11

The computer can be secure-erased and a new system installed so it may be useable to another person or donated, etc; some like the model for the look, others still use them for less intensive projects, off and online.

There is a grey install-restore disc set that accompanied the computer when new, it should still follow it through the rest of its life; in part due to the complete restore install software set of OS X and applications it came with are on those original discs. Also, there is an Apple Hardware Test on one of those grey-colored, part numbered iMac G4 system discs. They are kind of like the keyboard, only more special to that model. As a part number, they are part of the complete computer and represent a license for the system it shipped with.

If you do not have the original DVD install-restore disc set with grey-label, depending on the processor speed of the computer, you may be able to use a retail full install DVD of Mac OS X 10.5 Leopard. You start the computer from the DVD's installer (hold C key down on startup until the disc loads and the computer reads the disc, to slowly set up the Installer) when there is a desktop screen, with Installer running, there are options in the finder-like menu bar at the top. Under one of them is Disk Utility. It can be used to wipe, erase, zero overwrite (single-pass, should be OK; or maybe 7-pass. Not 35-pass, that'd take many hours; maybe overnight.) The necessary options and choices to choose an Apple Partition Map, a Format (HFS+ journaled) and others appear in the Disk Utility.

Physical removal of the hard disk drive is not high on the list of do-ables, the HDD is a PATA or ATA/IDE and you'd need to get another replacement. Harder to find, harder still to replace. A tech should do that to be sure it is done correctly, and the PRAM clock battery also replaced while the case is open. This is very tedious and attention to detail is paramount to success. Thermal paste, correct torque, and tiny wires are involved.

The computer value varies depending on condition and model version. If it is a 700MHz or 800MHz model the early ones could dual-boot early Mac OS9.2 and OS X. They had 15" displays; a few had 17" displays. I had one with 17" display, superdrive, airport, 1GB RAM, and dual-boot capability; so it was preferred due to the premium upgrades, by those who had older software titles from the classic Mac OS era before OS X. The later iMac G4s included the last group of USB2.0 hardware, these did not dual boot OS 9 + OS X.

Like several kinds of things, depending on condition, local demand, and regional economies, the price can vary outside of model version. The last iMac G4 20" with all the accessories, and bluetooth/airport, in as-new condition in the original box with papers, manuals, etc, is worth more to someone looking for as-new. The last iMac G4 17" was similar, both have a PowerPC 1.25GHz processor and some internal parts are similar.

For a long list of Apple iMac Specs (All iMac Tech Specs) at everymac see:

http://www.everymac.com/systems/apple/imac/index-imac.html

For PowerPC iMac G4 specs, see links to each of the build models below:

•iMac G4/700 (Flat Panel) 700 MHz PowerPC 7441 (G4)

•iMac G4/800 (Flat Panel) 800 MHz PowerPC 7445 (G4)

•iMac G4/800 17-Inch (Flat Panel) 800 MHz PowerPC 7445 (G4)

•iMac G4/800 - X Only (Flat Panel) 800 MHz PowerPC 7445 (G4)

•iMac G4/1.0 17-Inch (Flat Panel) 1.0 GHz PowerPC 7445 (G4)

•iMac G4/1.0 15-Inch "FP" (USB 2.0) 1.0 GHz PowerPC 7445 (G4)

•iMac G4/1.25 17-Inch "FP" (USB 2.0) 1.25 GHz PowerPC 7445 (G4)

•iMac G4/1.25 20-Inch "FP" (USB 2.0) 1.25 GHz PowerPC 7445 (G4)

The use of a system DVD supported by the hardware is the best route

to erase and install a new system on the internal hard disk drive. The

retail DVDs that could do that, late enough to add value if the original

disc set has gone missing, would be retail Tiger 10.4 or Leopard 10.5.

(Note: for processors slower than 867MHz, you'd stick to Tiger 10.4.11)

You may be able to get a generic white label replacement OS X install

DVD from AppleCare or Apple Store main (online my apple#) and ask

to speak to a Mac operating system specialist. There is a fee involved

in getting a disc; they may not even know they have it available. If they

do have one or both, get both. That way you'd have at least one option.

At under $20 per system DVD, that is a bargain, if you can get them.

Better if you can find the original grey label discs, even if they only

have Panther OS X 10.3 on them; due to the AHT and software.

Good luck & happy computing! 🙂

{edited - fixed link errors}

The 35-pass overwrite secure method is not necessary, if you are going to keep on

using the computer or someone you know and presumably trust (family?) may be

the next users of the device. Simple use of the computer will more than completely

re-overwrite most of the hard disk drive free space and other space, eventually.

A single-pass or a seven-pass is adequate to check/fix the sectors or allocation

blocks of the hard disk drive, and also a third-party disk utility could be used if

it was of the correct vintage and type for the computer's two systems. For both

bootable install CD (or DVD) systems, you'd need to start with a C key held on

startup so the optical drive would be the default location to look for boot volume.

There are other keyboard commands and shortcuts, somewhere I have some

page links but don't have time now to locate them in the browser & test to see

if they're still good. Magical keyboard sequences? Some go way back.

The iMac you have, if a dual-boot machine, you'd want OS 9 Drivers to be on

the hard disk drive. That way, it will be able to run from OS 9.2, etc and not

just OS X. (Under Tiger 10.4, you can use OS9 applications, and the system 9

would be seen as a file under OS X; this has been called Classic. This use of

OS 9 applications does not need OS 9 Drivers, as Classic under OS X boot.)

Since Mac OS 9 was first, the earlier system, it would be that way in order of install.

To be sure the Drivers for OS 9 and partition map were OK for dual booting. Early

Macs use a different format and partition map than later or intel-based Mac. So

you have one of those. You do not necessarily have to install Mac OS 9 if you may

not see a need for it, but should install OS9 Drivers. A Tiger or Panther OS X

should have the option for installing those drivers on initial setup of the OS install.

If they are needed but not installed then, you'd have to totally start over and have

the main installer put them on the hard disk drive, in order to boot Mac OS 9.

Without closely looking at the install-restore disc set, I'd be having to guess on

some important (to me) details & choice or direction of use when installing them.

There should be a first disc of the series, that when put into a working Mac, could

be seen as having an OS X or OS 9 system, a bootable file, as part of Installer.

The disk tools on the install disc are part of a reason why there is a bootable file

on the first disc (in CD pkg or DVD set) so the hard drive can be addressed by

the tools and set up for a system installation. That's how repair tools also work.

The 'unmounted' hard disk drive can be accessed from an external source to

modify, fix, restore, etc content. Or totally erase. Sometimes mistakenly.

Some of the familiarity with a system has to be known while a computer of the

type, kind, or model you expect to be working with is completely functional. It is

harder to figure out how things worked after they're disassembled, unless you'd

had more than a passing interest & had depth in observing how things work...

I know of some people who totally take apart a small engine, when a simple thing

was wrong and it would not run; instead of learning how to troubleshoot by rote

where one would see what it would take to make it run, first. Not dissect altogether.

So that can be an extreme example, yet computer users do it, too; or the other

extreme is to want a quick fix and don't want to open the hood of their car to add

oil or check anything; but grouse about the repair or car replacement cost later.

Well, I have to get ready to take an elder to medical appointments, and so I have

to go and do that. The duration of these events that I'd do in 65 minutes can be

over 4 hours with certain persons who utilize time & resources differently...

Good luck!😐