HP 9845C

The HP 9845C from Hewlett-Packard was one of the first desktop computers to be equipped with a color display and light pen for design and illustration work. It was used to create the color war room graphics in the 1983 movie WarGames.^[4][5]

HP 9845C

Developer	Hewlett-Packard
Type	Desktop computer
Release date	1980[1]
Introductory price	US$39,500 (today $150,700)[1]
Discontinued	1984 (being outcompeted by the 200 series)[2]
CPU	Standard 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]
Memory	64 - 1600 KB RAM 128 KB ROM[1]
Graphics	560 x 455 pixels @ 3 bpp (8 color)[1]
Power	Mainframe: 275 W (max), CRT display: 550 W (max)[1]
Weight	48.1 kg (106 lb)[1]

HP 5061-3001 16-bit 4-chip hybrid processor used as the LPU & PPU processors in the HP 9845 series computers. Contains the BPC, IOC, EMC and AEC die.

Features

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, the BPC, with roots in the HP 2116A which were one of the first 16-bit microprocessors created.^[6]

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.^[7]

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

• HP 9800 series HP desktop computer product line
• HP DC100 - DC100 tape format and drive
• LDS-1 (Line Drawing System-1)