HP 9845C

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HP 9845C
HP 9845C.jpg
TypeDesktop computer
Release date1980[1]
Introductory priceUS$39,500 (today $120,111.27)[1]
Discontinued1984 (being outcompeted by the 200 series)[2]
CPUStandard option 1xx:

2 x 16-bit (LPU,[3] PPU) 3-chip hybrid processor with BPC, IOC and EMC

Enhanced option 2xx:
1 x bit-slice processor (LPU)
1 x 16-bit hybrid (PPU)

@ 5.7 MHz[1]
Memory64 - 1600 kB RAM ; 128 kB ROM[1]
Graphics560 x 455 pixels @ 3 bpp[1]
PowerMainframe: 275 W (max), CRT display: 550 W (max)[1]
Mass48.1 kg[1]

The HP 9845C was one of the first desktop computers in 1980 equipped with color screen and light pen for design and illustration work. It was used to create the color war room graphics in the 1983 movie WarGames.


The attached HP 98770A color display enabled the color graphics with its own CPU and separate power supply, a vector generator based on the AMD2900 bit-slice architecture, graphics memory with three planes of 32 kB each, the connection interface to the mainframe consists of a direct data bus attachment, and a light-pen logic.[1] 4913 colors were available.[1]

The system is a big-endian 16-bit architecture with roots in the HP 2116A which were one of the first 16-bit microprocessors created.[4]

The display showed 8 soft keys on the lower end of the screen, 39 alignment controllers behind a door enabled fine tuning of color convergence.[1]

The speed of the builtin BASIC language was accomplished by implementing time critical parts of it in CPU microcode.[1]

A builtin tape cartridge device with a capacity of 217 kB and transfer speed of 1440 bytes/s enabled storage of data.[1] Average access time for the unit is 6s and a rewind end to end takes 20s. The directory is stored in r/w memory to enable quick access.[5]

Graphics display speed (vectors/sec, overlapped and not clipped)
Option 1xx Option 2xx
For/Next ~95 ~145
Matrix Plot ~200 ~240
Absolute Plot ~5 000 ~5 000
Circles/s not clipped ~2 ~5

See also[edit]


  1. ^ a b c d e f g h i j k l "The 9845C". 2012-08-29. Retrieved 2013-06-30.
  2. ^ "HP Computer Museum". Retrieved 2013-06-30.
  3. ^ "The HP 9845 Assembler Project". 2010-02-21. Retrieved 2013-07-02.
  4. ^ "The 9845 System Architecture". 2013-06-09. Retrieved 2013-07-02.
  5. ^ "9845B/C CE Handbook" (PDF). 2009-08-17. Retrieved 2013-06-30.

External links[edit]