Honeywell 316

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Honeywell 316
Type 16-bit minicomputer
Release date 1969
Memory 4K to 32K words magnetic core

The Honeywell 316 was a popular 16-bit minicomputer built by Honeywell starting in 1969. It is part of the Series 16 which includes the Models 116, 316, 416, 516 and 716. They were commonly used for data acquisition and control, remote message concentration, clinical laboratory systems and time-sharing. The Series 16 computers are all based on the DDP-116 designed by Gardner Hendrie at Computer Control Company, Inc. (3C) in 1964.

The H-316 was used by Charles H. Moore to develop the first complete, stand-alone implementation of Forth at NRAO.[1] They were used as ARPANET Interface Message Processors (IMP) but could also be configured as a Terminal IMP (TIP) which added support for up to 63 Teletype machines through a multi-line controller.[2]

The original Prime computers were designed to be compatible with the Series 16 minicomputers.[3]

The Honeywell 316 also had industrial applications. A 316 was used at Bradwell nuclear power station in Essex as the primary reactor temperature monitoring computer until summer 2000, when the internal 160k disk failed. Two PDP-11/70s, which had previously been secondary monitors, were moved to primary.

Hardware description

The 316 succeeded the earlier DDP-516 model and was promoted by Honeywell as suitable for industrial process control, data acquisition systems, and as a communications concentrator and processor. The computer processor was made of small-scale integration DTL monolithic integrated circuits. Most parts of the system operated at 2.5 MHz but some elements were clocked at 5 MHz.[4] The computer was a bitwise-parallel 2's complement system with 16 bit word length. The instruction set was a single-address type with an index register.[5] Initially released with a capacity of 4096 through 16,384 words of memory, later expansion options allowed increasing memory space to 32,768 words. Memory cycle time was 1.6 microseconds; an integer register-to-register "add" instruction took 3.2 microseconds. An optional hardware arithmetic option was available to implement integer multiply and divide, double-precision load and store, and double precision (31-bit) integer addition and subtraction operations. It also provided a normalization operation assisting implementation of software floating point operations.

The programmers' model of the H-316 consisted of the following registers:

  • The 16-bit A register was the primary arithmetic and logic accumulator.
  • The 16-bit B register was used for double-length arithmetic operations.
  • The 16-bit program counter holds the address of the next instruction.
  • A carry flag indicated arithmetic overflow.
  • A 16-bit X index register was also provided for modification of the address of operands.

The instruction set had 72 arithmetic, logic, I/O and program flow control instructions.

Input/output instructions used the A register and separate input and output 16-bit buses. A 10 bit I/O control bus, consisting of 6 bits of device address information and 4 bits of function selection, was used. The basic processor had a single interrupt signal line, but an option provided up to 48 interrupts.

In addition to a front panel display of lights and toggle switches, the system supported different types of input/output devices. A Teletype Model 33 ASR teleprinter could be used as a console I/O device, and (in the most basic systems) to load and store data to paper tape. Smaller systems typically used a high-speed paper tape reader and punch for data storage. The Honeywell family of peripherals included card readers and punches, line printers, magnetic tape, and both fixed-head and removable hard disk drives.

A rack-mounted configuration weighed around 150 pounds and used 475 watts of power. Honeywell advertised the system as the first minicomputer selling for less than $10,000.

The Honeywell 316 has the distinction of being the first computer displayed at a computer show with semiconductor RAM memory. In 1972, a Honeywell 316 was displayed with a semiconductor RAM memory board (they used core memory previously). It was never placed into production, as DTL was too power hungry to survive much longer. Honeywell knew that the same technology that enabled the production of RAM spelled the end of DTL computers, but wanted to show that the company was cutting edge.[citation needed]

System software

Honeywell provided up to 500 software packages that could run on the H/316 processor. A FORTRAN IV compiler was available, as well as an assembler, real time disk operating systems and system utilities and libraries.

Kitchen Computer

An ad for the Kitchen Computer. The tagline is "If she can only cook as well as Honeywell can compute". A Honeywell 316 in a pedestal model is on display at the Computer History Museum, Mountain View, California

The Honeywell Kitchen Computer or H316 pedestal model of 1969 was a short-lived product offered by Neiman Marcus as one of a continuing series of extravagant gift ideas.[6] It sold for $10,000 ($63,730 in 2013 dollars), weighed over 100 pounds (over 45kg), and was advertised as useful for storing recipes. Reading or entering these recipes would have been nearly impossible for the average housewife or cook, since the user interface required the user to complete a two-week course just to learn how to program the device, using only toggle-switch input and binary light output. It had a built in cutting board and had a few recipes built in. No evidence has been found that any Honeywell Kitchen Computers were ever sold.[7]

The full text of the Neiman-Marcus Advertisement reads:

"If she can only cook as well as Honeywell can compute."

"Her souffles are supreme, her meal planning a challenge? She's what the Honeywell people had in mind when they devised our Kitchen Computer. She'll learn to program it with a cross-reference to her favorite recipes by N-M's own Helen Corbitt. Then by simply pushing a few buttons obtain a complete menu organized around the entree. And if she pales at reckoning her lunch tabs, she can program it to balance the family checkbook. 84A 10,600.00 complete with two week programming course. 84B Fed with Corbitt data: the original Helen Corbitt cookbook with over 1,000 recipes $100 (.75) 84C Her Potluck, 375 of our famed Zodiac restaurant's best kept secret recipes 3.95 (.75) Corbitt Epicure 84D Her Labaird Apron, one-size, ours alone by Clairdon House, multi-pastel provencial cotton 26.00 (.90) Trophy Room"

Although a fantasy gift, the Kitchen Computer represented the first time a computer was offered as a consumer product, except for Olivietti's Programma 101, which debuted at the 1964 New York World's Fair, and was for sale to the public.[8]


  1. The Evolution of Forth
  2. Lua error in package.lua at line 80: module 'strict' not found.
  3. Comp.Sys.Prime FAQ
  4. Honeywell H316 General Purpose Digital Computer, Honeywell publication 316C-96910
  5. Programmer's Reference, November 1970 retrieved 2010 Jan 31
  6. Lua error in package.lua at line 80: module 'strict' not found.
  7. Lua error in package.lua at line 80: module 'strict' not found.
  8. Lua error in package.lua at line 80: module 'strict' not found.

See also

External links