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Manufacturer Computer Control Company
Identification,ID DDP-116
Date of first manufacture-
Number produced -
Estimated price or cost-
location in museum -
donor -

Contents of this page:



The DDP-116 was designed by Gardner Hendrie and is the first 16-bit minicomputer. The memory cycle time is rated at 1.7 usec with memory available in 1, 4 and 8K-word modules. The instruction set has 63 commands. A paper tape machinepunch and teleprinter were standard equipment.


Special features

Historical Notes
from Bill McAdams
... started at 3Cs in Jan. of '64 working for Bill Sparks. Used to fire up the DDP-24s as they came off the production line and make sure they worked. ... Moved into Field engineering in June or July of '64 and transferred to the Los Angeles office in Nov. Saw the early 116s and liked them a lot. I installed most of the 116's west of the Mississippi in the mid 1960's. Became the West Coast expert on those and also fixed DDP-24, 124, and later the 516, 416, 316 line of machines. Installed Serial #1 of the 516 at Stromberg Carlson in San Diego.



The DDP-116 was announced at the 1965 Spring Joint Computer Conference. It was the first 16 bit machine. Prior to that time the company produced a 24 bit machine (DDP-24) and before that a 19 bit machine. The 116 was the first [ CCC?? ] product that used wire-wrapped wiring instead of the taper pin connections.

The basic 116 was housed in a single cabinet that did not have any multiply/divide hardware and used an ASR-33 Teletypewriter for an I/O device. Its speed was a blistering 10 characters per second. Typing was therefore slow but manageable but the reading and punching of paper tapes was a brutal experience that often failed.

An ASR-35 was sometimes used at additional cost but was more reliable in operation.

Memory was available in either 4K or 8K 16 bit word configurations. I believe the speed was 1.7 microseconds which was quite a jump from the 5 microsecond DDP-24.

The machine described so far cost $25,000 (for the 4K version). This was a significant reduction in computing cost when one considers that the basic DDP-24 cost about $75,000.

When a customer required multiply/divide capabilities an additional cabinet was required with a necessary power supply. This additional cabinet could also contain additional core stacks of 4 or 8K with the necessary supporting circuitry. Only 2 or 3 additional rows of cards were required. This left room for more optional hardware additions.

Additional speed when using paper tape was provided if the customer ordered a BRPE 1100 high speed paper tape punch which created tapes at about 100 characters per second. Some customers decided to avoid torn paper tapes by using mylar tape. It worked fine but the punch pins rapidly became dull and had to be replaced (the whole head was replaced).

Loading paper tapes was much less of a chore if the system included a high speed (300 cps) paper tape reader. I think the manufacturer was Digitronics.

The circuitry used to create the 116 was the same as that used to create the DDP-24. The electronics cards were called S Pacs and there were several different types. Cards that contained nand gates were called DI or DL. Flip Flops were FF or FA. Cards used to control memory were BR or SS. Each card contained multiple copies of a particular type of circuitry such as nand gates (up to 7 per card) or flip flops (4). The BR cards usually were Bit Register cards in memory. S-Pacs usually had a number after the letters that indicated the speed of the circuitry. My memory is a little vague here. Each S-Pac had 35 pins and a row in the cabinet had either 24 or 28 cards (canít remember).

The Assembler for the DDP-24 was modified to handle the 16 bit machine. Then a whole new collection of programs was created to run upon and/or test the 116. These programs were subsequently used on the DDP-516, 416, 316 and 716.

I can answer questions . . .

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Updated July 15, 2001