Sorry, the only photo I have is monochrome (linked above). Maybe Bob Bane has some color photos! It ran a "Dining Philosophers" simulation that did a lot of cool blinking, and I ported FIG-FORTH to it, which was great for writing LED blinking programs.
Laboratory for Parallel Computation and Z-MOB
Around 1980, Dr. Charles (Chuck) Rieger
(Figure 3.12) designed a computing system to
run as a network of processors. The initial
design consisted of 256 Z80A processors.
Each contained 64K memory, linked together
on a “conveyor belt” (a 48-bit wide slotted
ring architecture), as packets of information
were passed from one processor (or “moblet”)
to another. This “mob of Z80s” soon became
known as Zmob. The system was programmed
and controlled by a host VAX 11/780
computer. An Air Force Office of Scientific
Research grant was obtained for building the
basic Zmob hardware.
It was apparent to both Minker and Basili
(after addressing the crush of student majors)
that to be a top department, we needed more
equipment. Minker was behind the acquisition of the VAX 11/780 (Mimsy) in 1980, which was a good
start, but was insufficient. We needed terminals on every desk, additional machines like Mimsy, and a
laboratory under our own control. Computers were our technology and if we couldn’t have and control
our own machines, our research in this area would always be hampered.
In 1982 Basili organized a proposal team, consisting of Agrawala, Minker, Rosenfeld, Stewart, and
Weiser. They met and came up with the idea of a parallel computation laboratory, using some of the ideas
in Zmob as a starting point. A Coordinated Experimental Research (CER) proposal was written to NSF,
and in 1983 it was funded as a 5-year $4.3M grant. This grant greatly expanded the departmental
laboratory, purchasing machines tove, gyre and gymble, as discussed earlier.
PRISM, under the direction of Minker, was the core of the CER project. It was conceived as the
software system designed to run on Zmob, and was run as a simulator on the VAX. It used Horn clause
logic (similar to the design of Prolog) to implement AND/OR parallelism. Users could specify the
number of problem solving machines (i.e., moblets) to use, the number of database machines to use, and
the number of machines to handle executable procedures. Statistics were collected to determine how
effective the search strategy was. Users could also run PRISM in a sequential Prolog-like manner.
Continued Zmob research was funded by this grant and a
version consisting of 128 moblets was built and installed in the
Department laboratory (Figure 3.13). Moblets were accessed by
physical address or by pattern matching. Programming in Prolog like languages was seen as the mechanism for using Zmob. Mobix
was the operating system designed to run on Zmob, which would
hide many of the complexities of the Zmob hardware.
Due to inexperience in hardware design, Zmob ran, but not as
reliably as desired. The Z80s were 8-bit processors and became
obsolete too soon. 16 bit and 32 bit versions of Zmob were
designed, and a 16 node ring of 16-bit processors using the
Motorola 68010 processor, called McMob, was built and used for
several years. Initial design work for a further advancement,
called Chessie, was started, but a prototype Chessie was never
built. Work continued for several years, but after the NSF grant
that suppported most of the development ended, work slowly
stopped on that activity.
Mark Weiser’s foot “mole” of 1986 was another interesting
idea that grew out of the CER grant. Instead of using a mouse
controlled by the hand, a foot pedal was developed, eliminating
the need to move the hands off the keyboard in order to control
the screen. Several variations were built and tested on Sun workstations, but the concept never became
fully operational. Unfortunately for the Department, Weiser soon left for a research position at Xerox
Palo Alto Research Center and this activity also ended.
Funny story, in my undergrad I worked at UMIACS and we had to install a set of foot pedal mice buttons in an office next to Minker's. The user would move the mouse on their desk, but click with their feet.
