HP 9800 series

HP 9800 series
Company type	Product line
Industry	Computer hardware
Predecessor	HP 9100 calculator
Founded	1971
Founder	Hewlett-Packard
Fate	Replaced by personal computers from Apple and IBM
Successor	HP Series 80 family (HP 85, HP 87)
Headquarters	Loveland, Colorado; Fort Collins, Colorado; Corvallis, Oregon (Advanced Products Division), United States
Area served	Worldwide
Products	Programmable calculators and desktop computers (models include HP 9810A, 9820A, 9821A, 9830A, 9805A, 9815A/S, 9825A/B, 9831, 9835, 9845)
Owner	Hewlett-Packard
Parent	Hewlett-Packard

The HP 9800 series represents a range of programmable calculators and subsequent desktop computers created by Hewlett-Packard, following the HP 9100 calculator. The 9830 model and those that followed were complete computers equipped with a robust BASIC interpreter.

Second generation

Prominent units in this lineup include:

HP 9810A (1971), a keystroke programmable machine featuring magnetic cards and an LED display,
HP 9820A (1972), the first HP device to support algebraic entry and incorporate a high-level programming language later known as high performance language (HPL),
HP 9821A, closely resembling the 9820A but substituting magnetic cards with a software-driven Compact Cassette tape drive compatible with the HP 9830A,
HP 9830A (1972), the flagship offering that included a BASIC interpreter embedded in read-only memory (ROM).

All models from the 98x0 series and the 9821 shared identical input/output interfaces, allowing cross-compatibility throughout the series. An optional thermal printer capable of printing 400 lines per minute on 80 columns was designed to be mounted above the 9820 and 9830 units, enhancing their output capabilities for business use.

Third generation

Expanding upon the achievements of the HP9830, the third generation introduced faster processing components and included:

HP 9805A, released in 1973, an economical programmable calculator with interchangeable personality modules, housed in the same case as HP46 and HP81 handheld calculators.
HP 9815A/S, unveiled in 1975 as HP’s third-generation advanced RPN desktop computer, more compact, lighter, and cost-effective than its forerunner, featuring a single-line display and replacing card readers with tape drives.
HP 9825A/B, launched in 1976 and discontinued by 1983, offering HPL programming, a single-line alphanumeric screen, and an optional thermal printer.
HP 9831, a variant of the HP9825 running BASIC instead of HPL.
HP 9835, furnished with BASIC and serving as the basis for the HP 250 business computer series; available in two versions—model A with CRT display and model B with single-line display.
HP 9845, initially released as monochrome models (9845A/S), later upgraded to high-performance monochrome (9845B/T) and color versions (9845C/T), integrating tape drives and an optional thermal printer with an 80-column output positioned beneath the screen.

Except for the HP 9805, these devices utilized DC200 cartridge tapes instead of cassettes. The HP 9825, HP 9831, HP 9835, and HP 9845 shared common I/O interfaces, whereas the HP 9815 featured a distinct interface.

A precursor to modern personal computers

Originating from HP’s Loveland facility (Calculator Products Division) and subsequently Fort Collins (Desktop Computer Division), the HP 9800 series was initially labeled as "Calculators" to facilitate purchasing processes amid varying company policies regarding computers. This series paved the way for the HP Series 80 family—comprising models like the HP 85 and HP 87—which were smaller BASIC-based computers equipped with CRT displays developed by HP’s Advanced Products Division located in Corvallis.

During the late 1970s through early 1980s, these desktop systems competed against machines such as the Tektronix 4051, IBM 5100, and Wang 2200. Eventually, they were replaced by personal computers from manufacturers like Apple and IBM.

Applications of the HP 9830

The HP 9830 was adopted by aerospace companies such as Boeing and integrated into educational environments in locations like Arlington, Virginia, and Renton, Washington, where pencil mark-sense cards enabled classroom interaction. During the early 1970s, National Real Estate Exchange, Inc. utilized an HP 9830 system equipped with a built-in hard drive to pioneer real estate software solutions.

The U.S. Coast Guard employed HP9825A units for experimental teletype message forwarding and to manage LORAN radionavigation chain coordination. Furthermore, HP9825 models combined with Oscor software were used to score one-design sailing regattas at distant sites—including the 1976 World Fireball championships in Nova Scotia and Windsurfing contests held in Cancún and the Bahamas—chosen for their portability compared to unreliable telephone-based time-sharing systems.

Overview of the HP 9830

The architecture of the HP 9830’s processor resembled that of the HP 1000/2100 minicomputer family, featuring a 16-bit memory address space along with AX and BX general-purpose registers. Its computational power was on par with early IBM personal computers, capable of producing intricate three-dimensional plots such as the SIN(X)/X function with hidden-line removal within several minutes—a notable technological achievement during that era.

Software executed directly from ROM, necessitating a specialized subroutine call instruction that utilized a distinct stack register for return addresses, which supported advanced capabilities like recursion. Certain variants (for example, the 9835B) incorporated a single-line uppercase LED display capable of showing 32 characters, offering an early form of interactive editing including cursor positioning and line scrolling—features that anticipated later screen editor developments.

For data storage, the system relied on a computer-controlled cassette drive equipped with optical tape-end detection, allowing file retrieval by number; optional hard disk drives were also available. The built-in line thermal printer provided rapid output by printing entire horizontal lines simultaneously—surpassing the speed of many subsequent dot matrix printers and rivaling modern inkjet devices. HP applied this thermal printing technology in numerous later plotting and terminal products.

Programming

Although its processor derived from minicomputer designs, the HP 9830’s system software was reengineered to include an operating system and programming language embedded within ROM. It featured an interpreted BASIC dialect that was simpler than the FORTRAN language commonly used by engineers on HP 1000 minicomputers, enhanced by arrow keys for interactive line editing and variable inspection—capabilities uncommon before screen editors became widespread.

Users could assign custom functions to function keys labeled on paper overlays, introducing concepts that influenced subsequent screen labeled function keys found in Hewlett Packard and IBM terminals; these features have since become standard across devices such as calculators, banking terminals, and fuel dispensers.

The BASIC environment could be expanded through ROM cartridges that added functionalities like graphical plotting, matrix operations, and string manipulation—similar in principle to video game console cartridges. The Plotter ROM facilitated chart generation using user-defined or world coordinate systems rather than raw plotter units. These commands formed the foundation for HP’s device-independent AGL graphics language standard implemented across HP computers including the HP 1000 minicomputer and the HP 2647 graphics terminal. <syntaxhighlight lang="basic">

10 REMARK DRAW A PARABOLA
20 SCALE -1.0, 1.0, -1.0, 1.0
30 FOR X = -1.0 TO 1.0 STEP 0.10
40 PLOT X, X*X
50 NEXT X
60 END

</syntaxhighlight> Additionally, a bootable development platform based on UCSD Pascal was offered for programming within the HP 9800 series environment.

Overview of HPL Language

Instead of using variable names like A1 or J2, HPL employed numbered registers ranging from r1 up to r199999.

Here is a sample HPL script designed for the HP 9825 that produces a sequence of prime numbers:

0: fxd 0  
1: prt 2  
2: 1→P  
3: for C=2 to 1000000  
4: P+2→P  
5: for N=3 to P/3  
6: if int(P/N)*N = P; gto 3  
7: next N  
8: prt P  
9: next C

A notable characteristic was the use of the rightward arrow symbol, termed the gazinta ("goes into"), so the expression "1→P" would be verbalized as "One gazinta P."

Additional BASIC-Based HP Systems

The Data Terminals Division at HP introduced the HP 2647a, a BASIC-programmable variant of the HP2640 terminal, which incorporated AGL—a standardized set of HP 9830 plotter command protocols.

HP 2647 BASIC was fundamentally Microsoft BASIC enhanced with HP-specific plotting instructions, representing one of Microsoft's earliest substantial collaborations with a prominent computer manufacturer.

HP also ventured into handheld computing devices such as the HP-75, although these achieved limited commercial traction. The HP 9835 model laid groundwork for business-oriented systems, ultimately influencing the development of the HP 250 series.

In 1979, HP unveiled the HP 85, inaugurating the HP Series 80 line of desktop scientific computers. It offered a robust BASIC interpreter and was priced accessibly for individual professionals compared to the more costly HP 9845.

This division later transitioned into producing UNIX-based HP 9000 workstations and acquired Apollo Computer. The evolution of HP Basic culminated in Rocky Mountain BASIC, which remains in use to maintain legacy software on these workstations.

External links