Hard Drives and MPC3000
It is possible to use a hard drive with the MPC3000. It will need to be a SCSI drive in an external case (in other words, external SCSI hard drive). Just connect the external drive to the SCSI port on the MPC. The MPC has a 25-pin SCSI connector.
What size? Well, you can use just about any size with the MPC, it's just that the MPC will only use about the first 780Meg of space. 1Gig drives are pretty common, but they can be a bit noisy due to their older design.
Since the MPC uses it's own proprietary format, do not even bother attempting to connect this drive to your computer. You risk damaging the file system since PC's tend to `mark` foreign drives. So this makes the drive only available to the MPC.