Hewlett-Packard's first computer, the 2116A of the HP-2100 series, was developed in the late 1960s. It is a 16-bit word-addressed general purpose computer. Main memory is 4096 words (4K), expandable to 32K magnetic core. The memory cycle time is 1.6 microseconds.

There are two 16-bit accumulators, called A and B. There are two 1-bit flags, called Overflow and Extend. The program counter, 15 bits, is called P. All instructions in the standard instruction set are 16 bits long. Conditional branching is done with a conditional skip followed by a jump instruction.

Instruction overview

• Arithmetic – Add, Increment, And, Or, Exclusive or
• Program Control – Skip, Jump, Jump to Subroutine
• Shift/Rotate – Arithmetic and Logical Shifts, 16- and 17-bit Rotates
• Optional – Multiply, Divide, 32-bit Load and Store, 32-bit Shifts

Model overview

Early models (1966-1969)

Core memory, hardwired CPU. Essentially a PDP-8 that has been pumped up to 16 bits and two accumulators.

• 2116A
• 2116B
• 2116C
• 2115A
• 2114A
• 2114B

Second generation (1970-1974)

Core memory, microprogrammed CPU. An option allowed user microprogramming.

• 2100A
• 2100S

21MX (1975-????)

Semiconductor memory, expandable to 1,048,576 words (one megaword).

• M-series – 2105A, 2108A, 2112A
• E-series – 2109A, 2113A
• F-series – 2111F, 2117F

Introduction dates

According to the alt.folklore.computers (news:alt.folklore.computers) Big List the early computers were introduced at the following times:

• Hewlett-Packard 2116A – Nov 1966
• HP 2115A – Nov 1967
• HP 2116A – Sep 1968
• HP 2114A – Oct 1968
• HP 2000A – Nov 1968
• HP 2114B – Nov 1969

(Note the conflicting entries for the 2116A, also the presence of the 2000A which is a time sharing system and not an actual computer as such.)

References

• Moffatt, Jeff (1999). HP 2100 Hardware Info. (http://oscar.taurus.com/~jeff/2100/)