How old is mac computers?

The IBM SCAMP project (Special Computer APL Machine Portable), was demonstrated in 1973. This prototype was based on the PALM processor (Put All Logic In Microcode).

The IBM 5100, the first commercially available portable computer, appeared in September 1975, and was based on the SCAMP prototype.

References:

www.wikipedia.org

http://en.wikipedia.org/wiki/Laptops