The HP 9800 is a family of what were initially called programmable calculators and later desktop computers that were made by Hewlett-Packard, replacing their first HP 9100 calculator. It is also named "98 line". The 9830 and its successors were true computers in the modern sense of the term, complete with a powerful BASIC language interpreter.
Models
Second generation
Chronologically, the models of the family were: HP 9810A, a keystroke programmable computer with magnetic cards and LED display, introduced in 1971, HP 9820A, introduced in 1972, was the first HP model that deals with algebraic input (not only RPN) featured a high level language simpler than BASIC that was later named high performance language (HPL), HP 9821A, similar to the HP 9820A, however, with Compact Cassette tape drive with clear leaders instead of using magnetic cards. Tapes created on the HP 9821A could be read by the HP 9830A. Unlike later home computers which used standard cassette audio recorders which had to be manually put into record or play mode, it was completely controlled by software command, and could save and load to a file by number. HP 9830A, introduced in 1972, was the top of the 9800 line, with the addition of a BASIC interpreter in read-only memory (ROM). HP itself referred to it as a "calculator".
All 98x0 and 9821 systems used the same I/O interfaces. A 400 line per minute 80-column thermal line printer was designed to fit on top of the 9820 and 9830.
Third generation
The success of the HP9830 led to a next generation with faster logic: HP 9805A, the least expensive model using the same chassis as the HP46 (scientific) and HP81 (business) pocket calculators. This was a Programmable Calculator and had plug-in personality modules. It was introduced in 1973. HP 9815A/S, the HP 9815A was HP's third generation high end RPN desktop and was introduced in 1975. It was much smaller, lighter and less expensive than its predecessor. It provided only a single line display but replaced the earlier card drives with a tape drive. HP 9825A/B, introduced in 1976, and retired in 1983, featured HPL, a single-line alphanumeric display, and optional thermal printer, HP 9831, an HP9825 with BASIC instead of HPL, HP 9835, featured BASIC. There were two models, the A and B. The A had a CRT, and the B had a single-line display, HP 9845 introduced first as a monochrome (9845A/S), then a high-performance monochrome (9845B/T) and a high performance color (9845C/T) model. The 9845 came with one tape drive, and optional second tape drive and 80 column wide thermal printer integrated into the base under the pillar-mounted display unit. All the 98x5, with the exception of the 9805, used DC200 cartridge tapes, instead of cassette tapes. The 9825, 9831, 9835, and 9845 all used the same I/O interfaces. the 9815 had a unique I/O interface.
An ancestor of modern personal computers
The HP 9800 series were developed by HP's Loveland division (Calculator Products Division), and later Fort Collins division (Desktop Computer Division). Early desktop computers were marketed as "Calculators" to make purchasing easier. At the time, some companies had different procedures for purchasing "Computers".
They spawned development of HP series 80, namely HP 85 and HP 87, that were smaller BASIC language computers with CRT displays. They came from HP's Advanced Products Division based in Corvallis.
For a short time in the late 1970s and early 1980s there was a class of similar desktop computers, such as the Tektronix 4051, IBM 5100 and Wang 2200 - before they were replaced in the marketplace by personal computers such as the Apple and IBM PC.