The HP-87 was the follow-on model to the HP-85 in the 'Series 80'. It was a logical development, keeping the same processor and clock speed, but with the following changes:
• Basic language extended ie long variable names added, support for larger graphical display, total 48K in ROM.
• Allows programs to address memory above 64K, through use of an extended memory controller.
• HP-87 has 32K RAM built in, and allows up to 4 extra RAM modules of either 32K, 64K or 128K ie 534K max.
• Built in HP-IB interface, together with software support for basic I/O, mass-storage and printing without additional ROMs.
• Bigger screen allowing 80 column text, with either 16 or 25 lines.
• No built in tape or printer.
• Support for multiple (up to 5) binary programs in RAM.
The HP-87 was followed by the HP-86 and HP-87XM. The HP-86 lost the internal monitor in favour of an external monitor, and lost the built in HP-IB connector in favour of a Centronics parallel printer port and two connectors for HP floppy disks.
The HP-86 also had 64K RAM while the HP-87XM included 128K RAM. The final machine in the series 80 family was the HP-86B, which went back to having a built-in HP-IB port and featured 128K of RAM.
Thanks to John Shadbolt and his site for this information
END OF PRODUCTION
BUILT IN LANGUAGE
HP Basic interpreter
Full stroke 93 keys with numeric keypad and user definable keys
'Capricorn' custom HP 8-bit CPU
Custom HP I/O circuits
32 KB up to 534 KB max.
80 chars x 16 or 24 lines (software switch)
544 x 240 dots
SIZE / WEIGHT
Four I/O Ports, HP-IB
BUILT IN MEDIA
Built-in BASIC language. Optional CP/M O.S. Needed external FD/HD unit
Built-in power supply unit - 110V / 240V switchable