Macintosh Plus

The Macintosh Plus computer is the third model in the Macintosh line, introduced on January 16, 1986, two years after the original Macintosh and a little more than a year after the Macintosh 512K, with a price tag of US$2,599.

As an evolutionary improvement over the 512K, it shipped with 1 MB of RAM standard, expandable to 4 MB, a double-sided (800K bytes) disk drive and an external SCSI peripheral bus, among smaller improvements.

it was the first Macintosh model to include a SCSI port, which launched the popularity of external SCSI devices for Macs, including hard disks, tape drives, CD-ROM drives, printers, Zip drives, and even monitors. The SCSI implementation of the Plus was engineered shortly before the initial SCSI spec was finalized and, as such, is not 100% SCSI-compliant. SCSI ports remained standard equipment for all Macs until the introduction of the iMac in 1998.

Originally, the computer’s case was the same beige color as the original Macintosh, Pantone 453; however, in 1987, the case color was changed to the long-lived, warm gray “Platinum” color.

It is the earliest Macintosh model able to run System Software 5, System 6, and System 7, up to System 7.5.5, but not System 7.5.2.