HP-9830A
Manufacturer:Hewlett-Packard
Announced:December 1972
Available:Early 1973
Price:$5,975
CPU:Custom 4-boards @ 8MHz
RAM:4KB or 8KB
Display:32 character LED
 Optional thermal printer
StorageBuilt-in cassette drive
Ports:Printer, ROM and I/O
OS:'BASIC Plus' in ROM






Founded in 1935, Hewlett-Packard was known for their quality, professional electronic test equipment and signal generators.

In 1968, they introduced their first electronic computing device - the $4,900 HP-9100A desktop calculator.

Beginning in th early 1970s, HP released newer, more advanced systems to replace the aging and limited HP-9100A. These include the HP-9810A (model 10) in 1971, HP-9820A (model 20) in 1972, and the HP-9830A (model 30) in 1973.

The HP-9830A is the most powerful of the 9800 series of calculators. Calculators? Yes - most Hewlett-Packard documentation refers to the HP-9830A as a calculator - even the owners manual calls it a calculator. But the December 1972 Hewlett-Packard Journal (15MB pdf file from Hewlett-Packard Archive) declares "The BASIC-Language Model 30 can be Calculator, Computer, or Terminal. It has an alphanumeric keyboard like a teleprinter. Its language is BASIC. It can be used as a desktop computer or a remote computer terminal, yet it maintains the convenience and user interaction of a programmable calculator."

Additionally, according to HP.com, HP co-founder Bill Hewlett described the earlier HP-9100A: "If we had called it a computer, it would have been rejected by our customer's computer gurus because it didn't look like an IBM. We, therefore, decided to call it a calculator and all such nonsense disappeared."

The attractive and stylish HP-9830A is actually one of the very first desktop computer systems ever - it includes everything to fullfill that title, and as a bonus, it's entirely self-contained - practically portable:
  • A standard QWERTY keyboard for data and text entry.
  • An alphanuneric display - single line, 32 character LED.
  • A programming language - BASIC - an existing, standard computer language.
  • A method to load and store programs and data - the built-in cassette tape drive.

    • While the system memory is limited to only 4K (an additional 4K cost $1,475) - semiconductor memory was very expensive at the time - the operating system and BASIC programming language are store in permanent ROM, always available and leaving the main memory completely free for programs and data.



    Designed before the time of common computer microprocessor chips, the HP-9830A is comprised mostly of 7400-series gates, shift registers, and decoders. It requires sixteen (or more) circuit boards to operate:
  • CPU I/O register and device flags
  • CPU clock and I/O state machine
  • CPU registers and ALU
  • CPU microcode engine
  • BASIC ROM 1
  • BASIC ROM 2
  • ROM buffer
  • M-register
  • T-register
  • RAM 1
  • RAM 2
  • Keyboard logic
  • Display (LEDs)
  • Display controller
  • Tape drive control
  • Tape drive read/write
  • Tape drive motor control
  • Tape drive device interface
  • Up to eight optional internal/external ROM boards

    • All of the original HP circuit boards are gold plated. The 'green' ones are from Infotek Systems, of Anaheim California. Infotek was a popular provider of replacement boards, upgrades, and option ROMs for the HP-9830A and later models.

    The Hewlet-Packard HP-9830A is pretty big and heavy - 45 lbs / 20kg - but also very expandable with many options.
  • On the back there are four external slots to interface with printer, plotters, and other input/output devices.
  • Internally are three slots to install read-only-memory (ROM) modules for additional capacity and peripheral control.
  • Externally are five more slots for additional ROM modules, identical in function to the three internal slots. Each ROM module, costing about $485, is limited to 2K of data.

    • The built-in cassette drive holds up to 64K of data, with search speed of 26 ips (inches per second), and read speed of 10 ips - about 3K/sec. The cassette drive can be operated using control keys on the keyboard, or under computer program control.

    The optional, matching HP-9866A Printer ($2,975) is a full page-width, high speed, thermal line-printer capable of printing up to 240 lines per minute with 80 characters per line. It obtains its incredibly high speed (4 lines per second) by utilizing a thermal print head that is a full 80 characters wide - it doesn't even move while printing. It prints one row of dots, the full page wide, all at once. The paper scrolls while printing to complete the characters.


    Related Links

  • Old Calculator Web Museum - oldcalculatormuseum.com
  • The Museum of HP Calculators - hpmuseum.org
  • HP Computer Museum - hpmuseum.net
  • "Vintage Hewlett-Packard Archive"
  • Brent Hilpert's HP-9830A page
  • hp9830.com