Data Acquisition Corp. DAC-512
The Data Acquisition Corp. DAC-512 "Digital Computer"
Image Courtesy Charles Falconer
DAC-512 in use. Note electronics package containing the logic behind the keyboard unit.
Image Courtesy Charles Falconer
The Data Acquisition Corp. DAC-512 is a very early
programmable desktop electronic calculator. Although Data Acquisition Corp.
called the machine a "Digital Computer", it was most definitely a calculator,
albeit a capable programmable machine. At the time it was introduced
(mid-1965), it was arguably the most powerful desktop electronic calculating
The machine was designed by the founder of Data Acquisisition Corp., Charles
B. Falconer (9/13/1931-6/4/2012). Falconer was born in Geneva, Switzerland
Through his schooling, he studied physics, with a particular interest
in nuclear physics.
He worked at
Chalk River Nuclear, where he was deeply involved in the development of
computer software along with custom hardware used for simulation and managment
of nuclear power facilities.
He became well-known for his skills through his work at Chalk River,
which resulted in Falconer spending a lot of time traveling around the
world as an expert in the field.
In 1958, he left Canada to move to Boston, MA, a hub of technology enterprise.
with the intention of starting his own business
developing custom hardware and software
solutions for the nuclear power and other industries that needed precise and
fail-safe real-time control systems. He started up Data Acquisition Corp.
in Hamden, CT. In 1964, Falconer realized that some form of generalized
computing machine would greatly aid in the complex math required for
development of control systems, and the DAC-512 Digital Computer was developed,
with the first machine running in mid-1965. Initially, the machine was
a standlone programmable calculator, but shortly after it was introduced,
Falconer developed an I/O interface for the machine that allowed it to "talk"
to other equipment, such as reading the state of switches, temperature, pressure,
voltage, or other external devices, as well as actuating solenoids, relays,
and generating control voltages. With this interface, it became possible
for the DAC-512 to become the brains of a process control system.
The DAC-512 consists of two parts, a relatively small desktop
operator's console that contains the keyboard and Nixie tube display,
and another sizable (and heavy -- approx. 60 pound) box containing the calculating electronics.
The two units are connected by a cable that carries digital signals and power
The electronics package of the DAC-512 was built with
transistorized logic, and an 8K-bit magnetic core memory for working, program,
and memory register storage. There were about 40 circuit boards that
made up the electronics package, densely packed with components.
The machine was microcoded, but not in the traditional sense of
a microcode store that provides the microinstructions. Instead, the
microcode of the DAC-512 was hard-wired within the logic.
The machine operated with full algebraic logic, which had only been
implemented by Mathatronics up to that time, with one level
of parentheses. The machine provided the basic four math functions,
with operating speeds of addition/subtraction in 10ms, multiplication in 50ms,
and division in 70ms -- quite fast for the time.
The machine utilized true floating point numeric representation
with nine significant digits, and a two-digit exponent ranging from +50
to -49. The machine provided 120 memory storage registers, and a total
of 512 steps of program memory. Program memory was divided into eight
areas of 64 steps each. Each area could be used as a standalone program
or a subroutine. Conditional instructions allowed decision making within
a program, and program looping for iterative algorithms. A comprehensive
program library of advanced math functions was available to provide
higher-level math functions, such as logarithms, square roots, raising numbers
to powers, statistical functions, and much more.
Picker Nuclear-badged DAC-512, circa 1967.
Approximately 100 units were built and sold at a cost of $7500, but
due to poor marketing, and ever-increasing competition, Data Acquisition
Corp. lost money, and was purchased by Picker Nuclear in 1967, who continued
to market the DAC-512 under the Picker Nuclear name for a short time.
Various enhancements to the basic design were made during the machine's
short lifetime, including adding more memory registers, a teletype
interface, and others. Picker Nuclear, a division of Picker Corp.,
made its name in developing early Ultrasound medical imaging equipment.
The museum is looking for any examples of the machine, literature,
or reflections from anyone who may have had experience with the machine, either
at Data Acquisition Corp., Picker Nuclear, or were perhaps a customer of
these companies who used the calculator. Click the EMail button at the top of this page to contact the curator.