Let’s take a look at the hardware of the Macintosh Plus, the third Mac to be released, back in 1986, as the successor to the Macintosh 512K.
Here is a snippet:
“Following the release of the original Macintosh in 1984 and the Macintosh 512K in 1985, Apple released the Macintosh Plus in 1986, now with 1 MB of RAM, an 800 kB 3.5″ floppy disk drive, and a SCSI port. Let’s check it out.”
Link: http://www.hardwaresecrets.