I have a TRS-80 Model 16 with an 8 Megabyte drive, but unfortunately the drive is a secondary, not a primary, so it doesn't contain a controller and I can't actually use it with the Model 16 at the moment. Does anyone have an extra 8MB primary drive they'd care to part with? Or the controller board from inside an 8MB primary drive? (Or, for that matter, another secondary?) The Model 16 (or Model II) with the original hard disk interface[*] will ONLY work with 8MB drives, and not with the later 5, 12, 35, or 70 MB drives. Similarly, the 8MB drives will only work on the Model II or 16 with that original interface, and not on the Model I, III, 4, etc. The pinout and signals of the cable between the interface card in the computer and the controller in the primary drive is different than all of the later ones. Both the old and new TRS-80 hard drive interfaces use a 50-pin cable with signals similar to those used by a WD1000 controller, but neither are actually directly compatible with the WD1000 or each other. Radio Shack added some functionality beyond what the standard WD1000 has, and changed the pinout. Thanks, Eric [*] The original Model II/16 hard disk interface can be recognized by the red power distribution strips under the DIP ICs.