2nd hdd in iMac g4 20

kge420 · Feb 9, 2017

I have ordered a few 2.5" to 3.5" drive adapters along with a pata/sata adapter and want to know if it is possible to install two internal drives in my iMac. I am going to install a 320gb 7200 rpm sata laptop drive and just got to thinking if two drives are possible. The 3.5" 200gb 7200rpm pata drive is starting to sound like a Geiger counter! I'm not sure I really have the need to do this, just curious. I have taken the fan out for cleaning and lubrication and it's very quiet. Next is the loud hdd to be addressed.

dustinschings · Feb 9, 2017

If you replace the Optical with a HDD, I don't see why that wouldn't work. Also, if you could find a way to mount and power a second HDD, you could run it off the same IDE port as the first HDD if you get an IDE cable with a second plug on it but this is not ideal at all. Best way to have two would be to replace the Optical I would say.
[doublepost=1486666223][/doublepost]Also, I see you have a 20" that needs a logic board. Ever consider turning it into a monitor instead? I have wanted to do that to my 20" iMac for a while. I want the iMac to appear to still be complete, but it would just be a monitor/USB3 Hub/USB hard drive and optical, all internal to the dome still. Just a DVI port on the rear with a row of USB 3.0 ports to use, and one power cable and USB cable out. Then a HDD and Optical inside would be converted to USB and plugged into the hub, inside the dome. Basically, you would just leave it on your desk and connect it to your PC/Mac under the desk. This, IMO, is better than building one with a NUC inside for example, because you can use it with ANY computer, not just the one inside.

Eriamjh1138@DAN · Feb 9, 2017

The original DVD is PATA and I think uses Cable Select (CS). As long as your PATA/ATAT adapter supports this, putting a HDD/SSD should easily work.

kge420 · Feb 9, 2017

I don't want to lose the optical drive. This was just some thinking aloud and I'll probably not pursue it.

bunnspecial · Feb 9, 2017

The only way I can think of to make it work would be to remove the ODD. It's not a question of space but rather of bus availability.

Eriamjh1138@DAN · Feb 9, 2017

The IDE ports inside an iMac are not Master/Slave compatible, as far as I know. If you want to try adding a second drive to a given bus, install a new IDE cable with two ports, jumper the optical drive to master and add your HDD as slave (or vice-versa), and give it a go.

Please, let us know what happens.

kge420 · Feb 11, 2017

On my dead iMac G4 the odd and hdd are on the same cable, daisy chained so to speak. I'll have a look at the jumpers on the respective drives to see how they're set.

reukiodo · Feb 11, 2017

The iMac G4s with USB2.0 should have 2 PATA busses (2 separate cables from HDD/ODD to logic board).

If your iMac G4 officially boots to OS9 (without hacks), then there should only be 1 PATA bus which both HDD and ODD are connected to.

If you have the USB2.0 iMac G4 and a replacement cable long enough with two PATA connectors (3 total on the cable), then there should be enough space to put 2 laptop-sized drives inside where the previous 3.5" HDD was mounted.

Eriamjh1138@DAN · Feb 12, 2017

That's right. One PATA on early G4 iMacs, two PATAs on the last models.

kge420 · Feb 12, 2017

It's a 800mhz G4. The cable has 3 connectors.

Eriamjh1138@DAN · Feb 12, 2017

Yeah. You can either have a HDD and an optical or two HDDs. So either you decide to lose the optical drive to add internal storage and go with an external optical (which you really can't do with USB 1.1), or just upgrade the one HDD and stick with the setup.

Apple built the early G4s on the cheap.

Note, because there is only on PATA bus, technically, only ONE device on the bus can talk at a time. The other device has to stop talking to send data from the first. Adding a second HDD would not give you the same speed increase as two separate busses.

kge420 · Feb 12, 2017

Optical disk and 1 hdd on one bus and a hdd on the other? I notice that one of the pata connectors on the logic board is marked for 'hard drive'. Is that the only place a hdd can communicate?

Eriamjh1138@DAN · Feb 13, 2017

You have two IDE busses, right? (I think so).

You just need a three-way PATA cable and to set the jumpers to master and slave on whatever devices you squeeze in there on whatever bus you choose.

The Hard Drive marking is more for assembly and repair so one puts the cables in the proper ports, not what they are capable of. The factory cables won't reach if you mess then up.

If this works, it assumes that apple implemented the IDE bus in a way that still accepts M/S jumpers. They originally used a dedicated bus for the optical and HDD separately and configured them for Cable Select (CS).

Either it will work, or it won't! You have but to try it out and report back.

kge420 · Feb 13, 2017

2 ide busses is correct. I may give this a go at some point.

Intell · Feb 15, 2017

The USB 1.1 G4 iMacs only have one PATA bus, but two PATA ports on the logicboard and can only use a maximum of two PATA drives. Same goes for the eMacs.

CooperBox · Feb 15, 2017

kge420 said:
I have ordered a few 2.5" to 3.5" drive adapters along with a pata/sata adapter and want to know if it is possible to install two internal drives in my iMac. I am going to install a 320gb 7200 rpm sata laptop drive and just got to thinking if two drives are possible. The 3.5" 200gb 7200rpm pata drive is starting to sound like a Geiger counter! I'm not sure I really have the need to do this, just curious. I have taken the fan out for cleaning and lubrication and it's very quiet. Next is the loud hdd to be addressed.

I appreciate this may possibly be achieved, and for those who do, that's fine.
For myself the priority would be to just replace the HD by an mSATA SSD - something I keep saying I must get around to doing. Personally I'd hate to loose the optical drive, as (even when I'm not using a CD or DVD) I get great pleasure in pressing the keyboard eject button just to see it poke out it's 'tongue' once in a while. Imho just one of the many iMac G4 charms. I just couldn't be without one!

kge420 · Feb 15, 2017

As stated above I not keen on loosing the optical drive. Also a speed increase on this particular machine is not what I'm looking for either. Just looking to do something that I'm not sure can/has been done. Physical space is the great limiter along with pumping money into a 15 year old machine. trying to do this with available parts on hand.

Eriamjh1138@DAN · Feb 16, 2017

May I ask for what you plan on using the machine?

bunnspecial · Feb 16, 2017

Read what @Intell posted carefully.

It doesn't matter how many ports are on the LoBo-you're not going to get more than two IDE/ATA/ATAPI devices in one of these systems. Stick a two connector ribbon cable in and you're going to end up with a computer that doesn't boot.

If you want a second internal drive, your only option is to lose the optical drive. If you don't want to lose your optical drive, you have Firewire...

kge420 · Feb 16, 2017

Eriamjh1138@DAN said:
May I ask for what you plan on using the machine?

I have no real need for a 2nd hdd. This was a kind of 'try to see if it can be done' type of thing. This iMac is used for reading repair articles and for itunes. Thanks to all who replied with suggestions.

0248294 · Feb 17, 2017

What you could do, but I definitely would not suggest, is hacking in a second IDE or SATA drive by using a SATA/IDE to FireWire adapter, one as small as you can get, and soldering the FireWire connections from the adapter to the logic board. You would also need to tap power from the PSU to the adapter, and use small hard drives due to the lack of space. All this would be a very messy system with one FireWire port sacrificed to get two internal, bootable hard drives. But as I said, I really don't think anyone should even attempt this.

CooperBox · Feb 18, 2017

Eriamjh1138@DAN said:
Yeah. You can either have a HDD and an optical or two HDDs. So either you decide to lose the optical drive to add internal storage and go with an external optical (which you really can't do with USB 1.1), or just upgrade the one HDD and stick with the setup.

Apple built the early G4s on the cheap.

Note, because there is only on PATA bus, technically, only ONE device on the bus can talk at a time. The other device has to stop talking to send data from the first. Adding a second HDD would not give you the same speed increase as two separate busses.

I fear there has been a case of mis-information in this thread.
As the subject matter is the G4 iMac, I was frankly amazed to see the comment, "Apple built the early G4s on the cheap." Arguably the early G4 'snow' iBook may be considered an exception, but in my experience (and I've worked on many) the G4's both desktop and laptops are exceptional pieces of equipment, and in no way can be considered to be "built on the cheap".
As for the G4 iMac's, they are not only a piece of art, a wonder of technical acheivement, but also very ruggedly built, which obviously required an exceptional R&D effort, the manufacture of which in no way bordered on the cheap.

Eriamjh1138@DAN · Feb 18, 2017

Perhaps my comment was a little too strong. The cheapness was only with reference to using one IDE bus when they should have (and eventually did) use two.

iMacs have almost always used superior screens and materials when equivalent PCs were comparatively inferior. Only some education macs, the occasional use of 5400 RPMs HDDs, and, now, soldered RAM, are cheap moves by Apple to maintain their high profit margins.

Generally, with Apple, you get what you pay for.

reddrag0n · Jul 25, 2024

i know this is an old thread, and i saw it so i had to see if it's true...

short answer, yes, you can run more than 2 drives in an imac g4. i have done so in mine and no mine is not a 20". mine is the 17" 1ghz model and yes, it has 2 pata buses. for me this is only possible using brackets, adapters and very slim components.

i used an icydock slimline cd to 5.25" to hold the sata dvd drive.
i used a dual 2.5" to 3.5" hard drive adapter for the ssd and the storage drive.
i used 3 starteck ide to sata adapters and various extensions and bends in order to make everything fit and work in the imac.
i used a dual ide cable from an mdd to connect the hard drives, and the regular cd cable to connect the cd.
up top it's a tight fit with the sata adapters but no metal is touching due to the ata cable being plastic and bulging out just a hair more than the adapters.

here are some pic, i was in my glory and i didn't take some pics in the middle figuring out how everything fits together, but the beginnings you will get the idea and pics of the end result.