Tech question re: EIDE Hard Drives and Macs (revision D iMac)

[Wonk]

First, let me say that I'm not much of a hardware geek, but I'm not completely clueless either. IDE drives are new to me, since I cut my teeth on SCSI.

My Drive that came with it is, as of today, super flaky. Sometimes right out of the blue it makes a loud CLUNK CLUNK CLUNK and then the computer crashes. I'm currently backing up my important files (incrementally, between crashes) to my other computer to burn to CD, and plan to go buy a new hard drive tomorrow, but want to be sure I get one that's compatible.

I'm almost positive that the drive that shipped with it is a 40 pin IDE ATA/66 (correct me if I'm wrong, please), and my questions are:

What's the difference between EIDE and IDE? Could I install a 40 pin EIDE drive and have it work just fine?

Would an ATA/100 (or faster) drive work too? Would the faster speed be useable or limited by the iMac's bus?

What's the difference between Ultra ATA and ATA? Would an Ultra ATA drive work just fine for me? Any benefits over regular ATA?

The reason I ask is there's a sale nearby (so I could pick it up tomorrow) with an 80 GB Western Digital EIDE drive advertised for $120, which sounds like a good price for that. No other details are in the ad, so I don't know if it's Ultra ATA/100 or what, and was wondering if that'd be a problem if it was or not?

Thanks in advance to the DU hardcore hardware techies for your help.

[oldleftguy]

1. Question:

Was the old drive a mac super drive?

[Wonk]

2. Nope. DVD&CD player, neither burner. I copy over my LAN to burn. nt

[BigMcLargehuge]

3. looking for specific HD type into

I had that same problem It's means a mechanical failure in the drive and it needs to be replaced.

here are the steps required to swap a new drive in:

http://www.theimac.com/drive_steps.shtml

I will look for the IDE/EIDE stuff now.

[BigMcLargehuge]

4. Eureka!

the answer from our friends at lowendmac.com

http://www.lowendmac.com/macdan/03/0307ek.html

Hard Drives

The iMac's 4 GB hard drive was thought to be huge when it first rolled out. However, with huge office programs and 1000+ song MP3 collections, a larger hard drive will probably be necessary. For most people, the 40 GB hard drive found in today's 600 MHz iMac will probably be sufficient. But for people with the smaller hard drives found in earlier iMacs, upgrading to a larger hard drive might be an appropriate option.

The older iMacs use the common IDE hard drive interface, so finding a compatible hard drive shouldn't be a problem, and when you do find one, it shouldn't be too expensive either. You'll probably make your iMac faster at the same time, since today's hard drives tend to be faster than the ones Apple put in these iMacs.

If you have a Rev. A-D iMac, add a hard drive bigger than 8 GB, and there's any possibility at all that you'll run OS X on it at some point, be sure to partition the drive with a first partition no larger than 8 GB. This is the only way you'll be able to boot OS X on these older iMacs.

[Wonk]

6. Thanks for both those links. Very helpful :-D

:D

I've got some reading to do, and swapping in the drive looks a bit more complicated than any other drive swap I've done before, but do-able.

Thanks

[Prisoner_Number_Six]

5. The hard drive standards are an evolving progression

Newer computers are backward compatable with older drives, and access speeds are limited to the mechanics of the drive, which cannot be changed. IDE is obsolete, and has been replaced with EIDE (Enhanced IDE), and the ATA and Ultra ATA are steps up in access speed and size based on the old standards. (Not an overly techy explanation, but different drives have different access times, etc., so it's a matter of chosing based on what's in front of you at the time, mostly.)

I personally have soured on Western Digital, as their drives (for me) have a history of premature death. I would have recommended IBM, but they just sold their hard drive division, and new IBM drives are limited to current stock. Maxtor is okay, followed by Seagate. All these choices are based on personal experience with each brand, and may not reflect the wider reality.

You can upgrade an older computer to read a latest-generation hard drive by simply buying a plug-in controller card. A generic one will probably work as well as an expensive name brand card.

Confused yet? If not, I can continue rambling... :evilgrin:

[Wonk]

7. What about newer drives being backwards compatible with older comps? nt

[Prisoner_Number_Six]

8. It will read the new drive at the speed of the standard

the computer's bios is designed for, if the bios sees it at all, which it probably will. As I said, to read the new drive at full speed, use an add-on controller card that matches the specs of the new drive.

[Wonk]

9. Ok, thanks. nt

[cosmicaug]

10. Can't help much with Macs

EIDE introduced increased drive capacity support throught a BIOS extension (breaking the 504 Megabyte barrier) and a few other enhancements. 40 pins sure sounds like IDE. I believe all the IDE drives drives made nowadays (and at the time of the iMac) would be considered enhanced IDE.

As to ATA/100 or faster, in theory, they're supposed to be downward compatible with the older controllers but they'd throttle down their burst transfer speed to whatever the host adapter supports. However, most of these burst transfer speeds are more theoretical than anything else as the limiting factor is often the sustained transfer speeds which are determined by the drive mechanism and tend to be much lower (so the performance degradation will be nowhere near what you might expect from the burst transfer speeds supported by the respective ATA standards).

I believe Ultra ATA is just another name for the higher transfer rate DMA modes (basically marketting jargon --in other words Ultra DMA 100 is the same as Ultra ATA 100). The newer higher transfer rate DMA modes (Utra ATA/100 & Utra ATA/133) use an 80 wire data cable (a lot of the wires being ground) with the 40 pin connector (older IDE drives used a 40 wire data cable). See http://www.wdc.com/en/library/ata/index.asp . DMA stands for Direct Memory access and is basically used in the DMA modes as a way to access memory with minimal intervention of the CPU (which evens things up a bit with SCSI since one criticism of IDE is that it tends to be more CPU intensive).

As to installation on your particular model, I don't see why it wouldn't work as long as it supports IDE. I imagine Apple must have something on their web site. Western Digital certainly seems to think their drives work on Macs that support IDE. Their Install guide has the following to say about installing on Macintosh (which I cannot necessarily decipher because I don't speak Macintosh):

Install the Hard Drive in a Macintosh System
You can install two IDE/ATA hard drives on the same cable with the Master/Slave jumper
configuration in the following Macintosh systems:

• Power Mac G4 and higher
  
• Power Mac G3 (blue and white colored, limited to certain configurations)
  
• Power Mac G3 All-in-One
  

A Power Mac with a U-shaped mounting bracket installed in the rear drive bay is capable of
supporting dual IDE/ATA drives, allowing two drives to be installed in that bay. For more
information on Master/Slave support on Power Macs G3/G4, refer to AppleCare
Knowledgebase Article 24342 at www.apple.com.
If your system does not support the Master/Slave configuration, you will be limited to
installing one IDE/ATA device per channel (for a maximum of two IDE/ATA devices).
The following is a summary of the steps necessary to install a hard drive less than 137 GB as a
secondary hard drive in a Power Mac.

1. Since Cable Select is the default jumper setting of your Western Digital hard drive, you
   must change the configuration to Slave (see page 7 for a diagram of the jumper block. The
   drive that came with the Macintosh is already designated as Master (Master ID=0, Slave
   ID=1).
   NOTE: Cable Select mode is not supported by Macintosh’s built-in IDE/ATA controller.
   
2. Install the hard drive in your Macintosh system with the Apple-supplied interface cable.
   
3. Use the Apple Disk Utility to format and partition the drive. The utility is located on the
   Macintosh operating system CD.

They also have a note instructing the user to look for alternative setup instructions and compatibility information in his original Apple Setup Guide or at http://www.apple.com/support

HTH,

[Wonk]

11. Thanks everyone for your answers. I understand EIDE better now.

I'm almost done backing up and I don't think I've lost any data, and I think I'll pick up a new drive tomorrow and install it myself with confidence that I haven't bought the wrong kind of drive for the computer.

re: Apple's SuperDrive (which was mentioned earlier in the thread), those aren't hard drives, they're CD-RW/DVD-R drives.

Thanks again for the informative answers :D