View source for HP-71B

{{Short description|Late 1980s programmable handheld computer}}
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{{Infobox Calculator
| name         = HP-71B
| image        = HP-71B_Taschencomputer.jpg
| caption      = HP-71B handheld BASIC computer
| entry        = [[Calculator input methods#BASIC notation|BASIC]]
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The '''HP-71B''' was a hand-held computer or calculator programmable in [[BASIC]], made by [[Hewlett-Packard]] from 1984 to 1989.

==Description==
Smaller and less expensive than the preceding model [[HP-75]], the 71B has a single-line 22-character [[liquid crystal display]], 64K system ROM and 17.5K user memory.  Priced at US$595 MSRP (US${{Inflation|US|595|1984|r=-2|fmt=c}} in {{#expr:{{CURRENTYEAR}}-1}}), it operates on four [[AAA battery|AAA batteries]] or on AC adaptor. Four plug-in ports permits ROM-based programs or additional user memory to be added.  Separate compartments could accommodate an optional magnetic card reader and an optional [[HP-IL]] interface (HP 82401A) that could be used to connect printers, storage and electronic test equipment.

The 71B was the first handheld to implement the [[IEEE  854-1987]] radix-independent floating-point standard.  Programming features included a real-time clock, programmable timers and subroutine calls with parameter passing and recursion.  It was also HP's first calculator based on the [[Saturn (microprocessor)|''Saturn'' processor]], later versions of which are found in the popular [[HP-48 series]] calculators and most more recent [[HP calculators|HP calculator]] models.

Since the hand-pulled magnetic cards (HP-75 compatible) could only store two tracks of 650 bytes each, the card reader (installed under the logo plate above the numeric keyboard) was not a very popular option.{{citation needed|date=June 2020}}  Larger storage capacities could be accommodated through HP-IL peripherals such as the 82161A cassette drive or 9114A [[floppy disk|diskette drive]] that were also battery-powered and portable, if rather bulky compared to the 71B.  Subsequently, memory expansion modules to fit the card reader compartment became available from third-party vendors.

Other third-party options included a [[bar code]] wand and application ROMs to plug into one of the four memory ports.  A HP-71 configuration with bar code wand and a custom application was widely used for data collection in the British Department of Health and Social Security (DHSS).

Unlike HP-75 or [[HP-41]], the 71B could also act as a device in a [[HP-IL]] loop controlled by another device, allowing several of them in the same loop, communicating with each other (or an HP-75 or HP-41) or sharing peripherals. Using an HP 82402 Dual HP-IL controller, it was even possible to connect one 71B to two HP-IL loops simultaneously, possibly as a controller in one and as a device in another.

The HP-71B could optionally be made compatible with the large volume of programs written for the [[HP-41]]  series of calculators via a plug-in ROM that emulated the HP-41 at about 5x the original speed.

==Internal Design Specification==
Another notable "feature" of the 71B was that HP sold to the public a series of documents (IDS: Internal Design Specification) containing the nearly complete internal engineering details of the unit.  A series of four IDSes were published about the software contained in the 71B's ROM; this included the complete source code (in assembly language) for the entire contents of ROM, and extensive additional design documentation of the ROM software.  Other IDSes were released covering the 71B's hardware, the Forth/Assembler add-in ROM, and the add-in HP-IL controller.

==External links==
* [http://www.hpmuseum.org/hp71.htm HP-71B at the MoHPC]
* [http://www.hp41.org/LibView.cfm?Command=View&ItemID=180 HP Journal, July 1984] Issue dedicated to HP-71B, articles on design and packaging (with exploded views)
* [http://mycalcdb.free.fr/main.php?l=0&id=823 HP-71B pictures] on [http://mycalcdb.free.fr MyCalcDB] (database about 70s and 80s pocket calculators)
* [http://www.hpmuseum.org/forum/thread-5286.html HP-71B Compendium] of information related to the handheld computer
*[https://hpmuseum.net/document.php?hwfile=2039 HP-71 Reference Manual]
{{HP calculators}}
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[[Category:HP programmable calculators|71B]]
[[Category:Pocket computers]]
[[Category:Computer-related introductions in 1984]]