HEWLETT-PACKARD 9831A DESKTOP COMPUTER
Contents

Description

Central Processing Unit

Plug-In ROMs

Specifications

Options

Catalog

History

Announcements

Photographs

  The Hewlett-Packard HP 9831 is a BASIC-language desktop computer introduced in mid-1977.

I am interested in finding any 9831 machines, ROMs, manuals, documents or other material, including information on the BPC processor. If you have any such equipment or documentation, please send me an e-mail!

The 9831 is very similar in mechanical and electrical design to the 9825 and nearly identical software-wise to the 9830 desktop computer. In fact, most of the internal parts are prefixed with 09825, meaning they were originally designed for the 9825 computer. For instance, the keyboard assembly is 09825-66537.

The 9831 BASIC operating system is incorporated into a slide-in ROM cartridge. It can replace the 9825A operating system and allow the 9825 machine to behave as a 9831.

DESCRIPTION
The HP 9831A is a desktop computer that can be used as either a stand-alone device or with peripherals in an integrated computing system for industrial, commercial and scientific applications.

One of the main features of the 9831A is its programming language, the powerful BASIC (Beginner's All-purpose Symbolic Instruction Code). Because BASIC is a commonly known computer language and is similar to English, it's easy to learn and apply to programming skills.

To increase the 9831A's capabilities, certain commands have been built in to handle alphanumeric string variables, advanced programming techniques, and input/output operations. In addition, you can work with up to 286 simple variables, 26 one- or two-dimensional arrays, and string variables which are limited only by the available memory space. Extra features like these provide you with greater programming flexibility.

To further enhance the 9831A's capability and at the same time simplify programming even more, you are provided with 24 user-definable Special Function keys (12, plus shift) which can be used to represent text, functions, or entire programs. Three line editing keys and 4 character editing keys allow you to insert, change, and delete characters and lines as well as provide other programming debugging aids.

Another special feature of the 9831A is the error message. If you make a mistake, such as mistyping a statement while programming, the word ERROR, a specified error number, and the line number in which the error occurred will appear on the light-emitting diode (LED) display. Each error message is also accompanied by a "beep".

Built into the 9831A is a 2-track tape cartridge drive. The storage medium, a high-density rapid-access tape cartridge, records up to 250,000 bytes of information and also features automatic verification after recording.

Other physical features of the 9831A include a 32-character LED display, a typewriter-link keyboard with upper- and lower-case alphanumerics, 3 input/output (I/O) slots for peripheral interfaces, and 4 read-only memory (ROM) slots.

The 9831A comes standard with 7162 bytes of read/write memory all of which are available for your use because the BASIC language interpreter is hardwired into the machine. In addition, the memory can be expanded up to 31,738 bytes.

The 9831A also allows flexible system expansion to meet your application's needs. You can choose from a variety of peripherals and software packs to configure a truly personalized desktop computing system.

CENTRAL PROCESSING UNIT
The 9831 (and 9825) use a three-chip central processing unit. The three chips are:
  • Binary Processor Chip (BPC)
    • 59 byte-addressable instructions
    • similar to HP 2100 and HP 21MX instructions
    • Two general purpose 16-bit registers (A and B)
    • Can address 32,768 bytes (16th bit indicates indirect addressing)
    • Program Counter P
    • Stack Pointer
    • Flags
  • Input/Output Chip (IOC)
    • 12 instructions
    • two stack pointers (C and D)
    • Two-level vector interrupt processing
    • Direct Memory Access (DMA)
  • Extended Math Chip (EMC)
    • 15 instructions
    • Binary data
    • Binary Coded Decimal (48-bit words, 12-digit mantissa)

The processor is discussed in the June 1976 issue of the Hewlett-Packard Journal.

PLUG-IN ROMS
To increase its fundamental capabilities, specific commands have been built into the 9831A, as previously mentioned. But, to further extend language capability and peripheral control even further, 2 plug-in ROMs have been designed for use with the 9831A - the 98218A Flexible Disk ROM and the 98223A/B Matrix/Plotter ROM.

The 98218A ROM contains statements and functions to fully regulate the 9885M Flexible Disk Drive. The 98223A/B ROM provides statements for matrix and array operations and for graphic output.

The A version of the 98223 contains statements necessary to control the 9862A Plotter, whereas the B version of the 98223 includes statements for the 9872A Plotter.

SPECIFICATIONS
STORAGE

Dynamic Range: +1099 to +10-99, 0,
-10-99 to -1099
   
9831A read/write memory: 7162 bytes
    Opt. 001: 15,354 bytes
    Opt. 002: 23,546 bytes
    Opt. 003: 31,738 bytes
(will not operate with 98223A/B ROM)
   
Cartridge memory: 250,000 bytes
(varies with file length)
    Typical access rate: 14,300 bytes/s
    Average access time 6 s
    Search speed
        (bidirectional)
2286 mm/s (90 in./s)
    Read/write speed: 559 mm/s (22 in./s)
    Transfer rate: 2750 bytes/s
    Typical rewind time: 19 s (end to end)
    Typical erase time: 40 s (1 entire track)
    Tape length: 42.67 m (140 ft) - 1 track
    Number of tracks: 2
    Error check: check sum
    File length: programmable

OPTIONS AND ACCESSORIES
Item HP Part Number
Operating and Programming Manual 09831-90000
System Test Booklet 09831-90031
BASIC Reference Book 09831-90010
Test cartridge 09831-90035
Peripheral Control Manual 09831-90020
Utility pack 09831-10000
Dust cover 9222-0495
Tape head cleaner 8500-1251
Special Function Key overlays (5) 7120-4802
Vinyl carrying case 98025A
Blank data cartrdige 9162-0061
Software binder 9282-0563
   
16-bit Parallel I/O Interface
    transfers information between 9831A and 9830A/B Computers
98032A, Opt. 030
Serial Interface
    provides bit serial communication between 9831 and asynchronous EIA RS-232-C devices
98036A, Opt. 031
CATALOG
The 9831 only appeared in the 1978 catalog. The catalog copy read:

The HP 9831A is a destop computer that can be used as either a stand-alone device or with peripherals in an integrated computing system for industrial, commercial and scientific applications.

One of the main features of the 9831A is its BASIC language. Because BASIC is a commonly known computer language and is similar to English, it is easy to learn. At the same time the 9831's BASIC is powerful enough to meet the demands of experienced programmers.

To facilitate programming, string variables and general input/output commands have been built into the 9831. These enable the machine to accept and manipulate alphanumeric information and also provide for basic peripheral operations. In addition there are 24 Special Function keys (12 with shift, 12 without) which can be used to represent text, functions or entire programs with keystroke simplicity.

For fast storage and retrieval, a two-track tape cartrdige drive has been built into the 9831A. The storage medium, a high-density, rapid-access tape cartridge, records up to 250k bytes of information and also features automatic verification of data.

The 9831A comes standard with 7,162 bytes of read/write memory and is expandable to 31,738 bytes. Other features of the 9831 include a 32-character LED display, a typewriter-like keyboard with upper- and lower-case alphanumeric and three I/O slots and four ROM channels for extending language capability and peripheral control.

Features

  • Alphanumeric keyboard
  • 32-character LED display
  • Built-in tape cartridge drive
  • Hardwired BASIC language
  • Add-on read-only memory (ROM)
  • Expandable read/write memory
  • Up to 12 significant digits
  • Full trigonometric capability
  • Boolean algebra capability
  • 12-24 Special Function keys (shift included)
  • Broad range of peripherals

HISTORY
The 9831A was conceived in early 1976 as a business product for the new Fort Collins Division (FCD), a spin-off of the Calculator Products Division (CPD), which made the 98xx-series desktop calculators (9810, 9820, 9830, 9825, followed by the 9835 and 9845).

The 9831A project was known internally as "Bucs 77" because it was intended to generate revenue in 1977 for the newly-created FCS. The idea was to port the 9830A BASIC firmware to the new 9825A hardware and then port the existing 9830A business applications to this new platform. The 9830A BASIC code, minus math and I/O, was combined with the 9825A math and I/O code to produce the 9831A.

Except for the strip printer and the replacement ROM drawer and plug-in option ROMs, the 9831A and 9825A hardware was identical, and the 9831A ROM drawer could be directly used in a standard 9825A.

ANNOUNCEMENTS
One publication that carried the announcement of the 9831 was the May 1977 issue of IEEE Spectrum magazine.

Desktop Basic computer has 8k bytes of memory

The HP-9831A desktop computer, priced at $7200, can be used as a stand-alone, Basic-language computer or linked with peripherals to form systems. It comes with 8k bytes of memory, which is expandable to 32k bytes in 8k-byte increments. Basic language commands for string variables, input/output for peripheral control, and "advanced programming II" operations are built-in.

The computer features a built-in, bidirectional tape drive with an average access time of 6 seconds. "Strings variables" programming permits handling of string arrays as large as the total memory of the machine. Input/output to a plotter and flexible disks and other peripherals are provided.

The keyboard has 12 special-function keys that, with a shift function, can handle 24 different operations. The 32-character LED display provides upper- and lower-case alphanumeric readout and covers the full ASCII character set.

Hewlett-Packard Co., 1501 Page Mill Rd., Palo Alto, Calif. 94034.


The May 1977 COMPUTER magazine also carried an announcement:

HP offers Basic-language desktop computing system

The new 26-pound HP 9831A desktop computer can be used as a stand-alone, Basic-language computer or linked with peripherals to form systems, according to its manufacturer, Hewlett-Packard.

The HP 9831 comes with 8K bytes of memory, expandable to 32K bytes in 8K byte increments. Basic language commands for String Variables, Input/Output, and Advanced Programming II operations are built in. String Variables programming permits handling of string arrays as large as the total memory of the machine. Optional matrix/plotter flexible disk ROMs, providing such standard matrix operations as inversion, transportation and multiplication, and two-dimension array operators, are also available.

The desktop computer can work with master and slave flexible-disk drives for additional, fast-access memory; plotters; thermal- and character-impact printers; and CRT terminals. It features a built-in bi-directional tape drive. With 90-ips search and rewind speed and a 22-ips read/write speed, the tape cartridge drive gives an average access time of 6 seconds.

Most software pacs available for use with the HP 9830 desktop computer are directly compatible with the 9831, and program transmission between the two can be accomplished in seconds, according to the company.

The 9831's keyboard has 12 special-function keys that, with a shift function, can handle 24 different operations. The keys can accomodate complete programs and can serve as immediate-execute keys, call keys for subroutines, and as typing aids.

Error locations are identified by a cursor in the display. Fixed- and floating-point formats can be set by the user from the keyboard. The 32-character LED display provides upper- and lower-case alphanumeric readout, covering the full ASCII character set.

The 9831's tape cartridge has two tracks and can hold 250K bytes with a 2750 byte-per-second transfer rate. Using the cartridge, the operator can perform rapid memory-load and record operations.

The 9831 comes with 8K bytes of internal read/write memory, which is expandable in optional 8K increments to a total of 32K bytes. Four plug-in slots in the front of the computer provide space for optional ROMs. Through as many as three interface cards, the 9831 will work with standard HP peripherals.

Initial customer deliveries of the new 9831A desktop computer, priced at $7200, were scheduled to being in March.

PHOTOGRAPHS
 
 

Plug-in ROM
HP 98218A
9885 Flexible Disk ROM

 

09831-67905
BASIC Language plug-in ROM for use in the 9831A


Comments to Webmaster
Last updated June 26, 2012

Thanks to Art Boyne for his recollections on the development of the 9831A.