HP 2116A

HP 2116A. The HP 2116A was a pioneering minicomputer introduced by Hewlett-Packard in 1966. Designed initially as a controller for the company's line of test and measurement instruments, it evolved into a versatile general-purpose computer. Its robust architecture and I/O capabilities made it a significant product in the early commercial minicomputer market, influencing later HP computer families.

Overview

Announced in November 1966, the HP 2116A marked Hewlett-Packard's first foray into the commercial computer market. It was developed by a team led by engineers like Paul Ely and Tom Whitney, responding to the need for automated control in laboratories. Competing directly with established models like the DEC PDP-8, the 2116A found success in scientific, industrial, and educational environments. Its introduction coincided with the rise of computer-aided engineering and real-time data acquisition.

Design and features

The HP 2116A utilized a 16-bit word length and a memory-mapped I/O architecture, which simplified interfacing with external devices. Its printed circuit board construction and modular backplane design enhanced reliability and serviceability. A key innovation was its extensive Direct Memory Access (DMA) channel system, allowing high-speed data transfer from peripherals without burdening the CPU. This made it exceptionally well-suited for connecting to oscilloscopes, digital voltmeters, and other HP interface bus instruments.

Technical specifications

The system's CPU operated at a clock speed of approximately 1 MHz. Standard magnetic core memory ranged from 4 KB to 32 KB, expandable through external cabinets. It supported up to 16 priority-interrupt levels and 16 DMA channels. Physical I/O was handled through a flexible plugboard system and later the HP Interface Bus (later standardized as IEEE-488). Typical peripherals included teleprinters like the ASR-33, paper tape readers, and early hard disk drives.

Software and programming

Initial programming was done in assembly language or machine code, often entered via front panel switches or paper tape. A significant software advancement was the introduction of HP Time-Shared BASIC in 1969, one of the first time-sharing BASIC systems for minicomputers. This operating environment, developed by a team that included Bob Ragen, allowed multiple users to access the system concurrently via teletype terminals. Other supported languages included FORTRAN and ALGOL, facilitated by cross-compilers from larger systems.

Historical significance

The HP 2116A established Hewlett-Packard as a serious competitor in the minicomputer industry, challenging the dominance of Digital Equipment Corporation. Its design philosophy, emphasizing ruggedness and excellent I/O for real-time applications, set a standard for subsequent HP 21xx series machines. The computer played a crucial role in automating R&D laboratories and was used in major projects like the Arecibo radio telescope. Its success provided the foundation for HP's calculator and computer divisions, directly influencing the development of the HP 3000 business system.

Variants and successors

The original 2116A was quickly followed by the enhanced 2116B with faster memory cycles. The 2114A was a cost-reduced version with a smaller memory capacity. The most direct successor line was the HP 2100 series, which maintained software compatibility while offering improved performance. These evolved into the HP 1000 series, which continued the architecture for decades using LSI and VLSI technology. The 2116A's I/O bus concept lived on in the ubiquitous General Purpose Interface Bus (GPIB), standardized as IEEE-488. Category:Hewlett-Packard computers Category:Minicomputers Category:1966 introductions