The Macintosh SE has a number of new features and upgrades that its predecessor, the Macintosh Plus, does not:
- First compact Macintosh with a slot for a hard drive (originally 20 MB or 40 MB) or a second floppy drive.
- First compact Macintosh with an internal expansion slot.
- Uses the Apple Desktop Bus (ADB), first deployed with the Apple IIGS, as a keyboard and mouse port.
- Improved SCSI support with faster data transfers.
- Introducing the superdrive floppy drive. This allows the SE to read and write both Apple and MS-DOS formatted floppy disks.
- Improved stability and longer life due to the addition of a fan.
The SE was designed to contain either one or two floppy drives or one floppy drive in conjunction with one hard drive. Several configurations were possible, allowing for both two floppy drives and one hard drive. However, this configuration was not supported by Apple itself.