Yes, the hot swap feature with those trays depends on a little-known feature of Win 98. That is you can set the hard drives to removable in Device Manager. Not available in later versions of Win.
. You can use them as plain removable trays where you have to power down when swapping with the other versions of Win.
. If you want hot swap, use your drives in an external Firewire or USB case. Or you can get IDE to USB converter cables and make your mobile racks hotswappable via USB. Newegg, Compgeeks, et al. have the IDE to USB converter cables... It still won't be a simple turn the switch and swap the drives. The process should be explained in the instructions that come with the converter cable.
It will be obvious when you open up the drive cassette to mount the drive - basically the D connector (which is not a D connector, but a Centronics type connector like that on a parallel printer) has more than the 40 contacts needed for IDE - guess what some of the extra contacts are for...
And make sure that rack is ATA compatible if you want more than 33MB/s from your drive.
Here, have a :beer: !