As Wikpedia states: Sun-1 was the first generation of UNIX computer workstations and servers produced by Sun Microsystems, launched in May 1982. These were based on a CPU board designed by Andy Bechtolsheim while he was a graduate student at Stanford University and funded by DARPA. The Sun-1 systems ran SunOS 0.9, a port of UniSoft's UniPlus V7 port of Seventh Edition UNIX to the Motorola 68000 microprocessor, with no window system. Early Sun-1 workstations and servers used the original Sun logo, a series of red "S"s laid out in a square, rather than the more familiar purple diamond shape used later.
The first Sun-1 workstation was sold to Solo Systems in May of 1982. The Sun-1/100 was used in the original Lucasfilm EditDroid non-linear editing system.
As I have first personally heard Scott McNealy say, "the first serial number was 15 so customers did not think they were getting one of the first systems."
Something cool to check out is the SUN Workstation Architecture, Andreas Bechtolsheim, Forest Baskett, Vaughan Pratt, Stanford University Computer systems Laboratory Technical Report No. 229, March 1982
Another interesting tidbit of Sun history that I learned at the 25th anniversary of Sun Microsystems at The Computer History Musuem was that Vaughan Pratt was the person who designed the famous Sun logo.