How to Install an IOMEGA internal 100 Zip drive in a Power Mac G4

What OS is running on the G4? Assuming that it's a mini-tower, you can install an internal ATAPI Zip 100 or 250, depending on which better suits your needs. It would be connected to the same ribbon cable as the optical drive and should be configured for Cable Select, if that's how the optical drive is configured. If the optical drive is configured for Master, then set the Zip drive to Slave. You'll need to release the tabs that secure the blank bezel covering the expansion bay below the optical drive, then swing it out to release it on the left side. There were suppliers that carried specific Zip drive bezels for G3 and G4 Mac towers some years ago. At this point, ebay might be the best source for one, if you want a finished look.

Prior to the Mirrored Drive Door G4s, all previous G4 towers had a specially-designed, aluminum drive carrier for the 5.25" optical drive, with a narrower bay beneath it for the (optional) 3.5" Zip drive. If you have any of these earlier G4 models, you must install the bare drive beneath the optical drive in that carrier. The Mirrored Drive Door G4s had 2 full-sized, 5.25" bays. If you have a MDD G4 and want to use the sled that's included with the retail-boxed, internal Zip 100 or 250 drive, you may have to remove the beige plastic trim piece from the front to clear the MDD's main front panel.

I'd be reluctant to buy a used Zip drive at this point. Any fine lubrication used on the moving parts would likely be dried up by now. Also, there was a widely-known problem that many users experienced (referred to as the "click of death"), where an inserted disk wouldn't mount. The drive continued to make a clicking sound, while unsuccessfully trying to recognize the disk. Ejecting it was the only thing to do. Some users reported that problematic drives were physically damaging their disks. If you can find a new-in-box, internal Zip drive, you'd be better off.

A Zip 250 reads and writes Zip 100 disks, but takes longer to write to them and format them. Internal (ATAPI) Zip drives were never marketed for use in Macs, so it's unlikely that the very useful IomegaWare software suite would be included in the box. If you'd like to take the easier approach, you could just get a USB Zip drive and eliminate the installation headache. Since they were marketed for Macs & PCs, the IomegaWare software should be included. You can still find drives on ebay that the sellers show as "new in box," like this one. This is the 1st generation of Iomega's USB models and uses a DC power supply. The final, smaller USB versions were powered by the USB bus. In terms of reliability, there may be no definitive comparisons made between the models. The last USB Zip drive that Iomega produced was the Zip 750. At that time, CD burners were becoming popular and Iomega shifted its focus toward them.

I actually posted the wrong link for a 1st generation USB Zip 100 drive. The case resembled the parallel and SCSI versions, but the plastic was transparent. As an FYI, it can be seen here. The price is quite high, but some sellers think they're sitting on a gold mine, when they have a discontinued piece of tech hardware. As you saw, the link I provided was for the latter-style Zip 250, which was bus-powered.

Hi,

https://lowendmac.com/2015/low-end-macs-compleat-guide-to-zip-drive-and-disks/

(see Incompatibilities)

You're welcome! Good luck!