APPLE MAC PLUS COMPUTER MAC OS

The 800 KB drive has two read/write heads, enabling it to simultaneously use both sides of the floppy disk and thereby double storage capacity. The drive was still completely incompatible with PC drives. The then-new drive is controlled by the same IWM chip as in previous models, implementing variable speed GCR.

It has what was then a new 3 1⁄ 2-inch double-sided 800 KB floppy drive, offering double the capacity of floppy disks from previous Macs, along with backward compatibility. (Although 30-pin SIMMs could support up to 16MB total RAM, the Mac Plus motherboard had only 22 address lines connected, for a 4MB maximum.) By replacing them with 1MB SIMMs, it was possible to have 4MB of RAM. Four SIMM slots were provided and the computer shipped with four 256K SIMMs, for 1MB total RAM. The Mac Plus was the first Apple computer to utilize user-upgradable SIMM memory modules instead of single DIP DRAM chips. The Macintosh Plus was the last classic Mac to have a phone cord-like port on the front of the unit for the keyboard, as well as the DE-9 connector for the mouse models released after the Macintosh Plus would use ADB ports.

APPLE MAC PLUS COMPUTER MAC OS

It is the earliest Macintosh model able to run Mac OS System 7. 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. As an evolutionary improvement over the 512K, it shipped with 1 MB of RAM standard, expandable to 4 MB, and an external SCSI peripheral bus, among smaller improvements. 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$2599.

Apple mac plus computer