Michael Frank Deering: Hardware: Leo/ZX


Company: Sun Microsystems, Inc.

Year of Commercial Product Release: 1993

Product Code Name/Production Name

The internal code name for this project by was “Leo”, and this was also the name used in the title of the SIGGRAPH paper. However, as usual, the official name the product was different; the commercial name Leo sold under was “ZX”. Why a two character product name? Very simple: in those days the Sun internal product option ordering software could only handle two character labels (names).

Engineering Teams

External vendors supplied custom CMOS circuits as well as back-end support, chip fabrication, and testing. On the software side, other teams supplied OS drivers, XGLTM drivers and support, and extensive test cases. My role on the ZX was as chief architect, but many other people contributed at a high level, most prominently including Scott Nelson.


ZX was my second Sun 3D graphics accelerator product. At the time of release it was the fastest, least expensive, and physically smallest product in its class from any vendor. In the comparable SGI product of the time (Elan/Extreme)(paper given in the same SIGGRAPH session as Leo) just the video back end board was the size of the entire ZX product. By several metrics, the ZX was the most successful of my Sun 3D hardware products, in part because it was on the market for so long while management was delaying my next product (Elite 3D).

In many was the ZX was the GT done right: all custom chips except the VRAMs (and the next machines would fix that).


This was the presentation made about the Leo/ZX chip set at HotChips V (1993):

Michael F. Deering “A Compact 3D Graphics Chip Set” in HotChips V (1993). (Commercial product name ZX.)

pdf (386 KB) (minus photo of HW)

The main publication was the SIGGRAPH paper:

Michael F. Deering, Scott R. Nelson “Leo: A System for Cost Effective 3D Shaded Graphics” in Proc. SIGGRAPH ’93.

pdf (362 KB) (minus photo of HW)