• D3B_4323

Philips P859

Minicomputer

Manufacturer:Philips
CPU Architecture:P800
Introduction:1980
Dimensions (WxHxD):48 x 27 x 55cm
Bus:GP
CPU: Philips CP7RA
Memory:512KW = 1MB 21-bit ECC RA (max. 512KW = 1MB)
Storage:X1215, X1215 Emulator, 3 x cassette drive, 2 x 8" floppy drive
Peripherals:Serial terminal
Condition:Fully operational
Acquired:2012
Donated by:Bert Thomas
  • rck_D3B_4321

Characteristics

CPU CP7RA, 16-bit CPU built around Am2900 slices
Memory 512 Kword (265KB) 21-bit ECC RAM
I/O Slots 10 GP Slots
Enclosure M4 (48cm x 27cm x 55cm, 6U)
Introduced 1980

Description

The Philips P859 was part of the third and last generation of minicomputers in the P800 family. While other systems of this generation are built on double-euro-size cards (200 x 160 mm), the P858 and P859 are built around the older large square card format with the GP bus in the middle. My guess is that this was done to let customers preserve their investment in I/O cards.

I believe that the difference between the P858 and P859 was that the first used core memory and the latter uses MOS RAM. The P858/P859 reference manual doesn't describe the differences anywhere, but there's a table in section 1.15 that lists memory options and their applicable system. P858 is listed against all core memory modules, and P859 against all MOS memory options.

The P858 and P859 have an expanded memory management unit built into the CPU, that allows up to 512 Kwords of memory to be addressed (the Philips P857 with its MMU could address up to 128 Kwords). This requires 2 extra address lines on the GP bus, which need to be added using wire wrap technique for those cards that need it.

My P859 enclusure is filled with the maximum of 10 cards. I don't have a floating point processor. The P859 is connected to the following peripherals:

  • Serial console
  • X1215 cartridge disk drive
  • X1215 emulator (PC + FPGA based)
  • P830-010 enclosure with 2 8" floppy drives
  • P833 enclosure with 3 cassette drives

The picture of the entire rack shows (from top to bottom): 2 8" floppy drives, 3 cassette drives, P857, X1215, control panel for emulated X1215, P859.

Modules

1 CP7RA CPU
2 M128E 128Kword RAM
3 M128E 128Kword RAM
4 M128E 128Kword RAM
5 M128E 128Kword RAM
6 IOP First I/O Processor
7 MCU3 Serial port, paper tape reader and punch interface
8 MCU2 Card reader and line printer interface
9 CDD Cartridge Disk Drive controller
10 FM1B 8" Floppy Disk controller
CC K7S2 Cassette Drive controller (in cassette drive enclosure)

Read about this system's acquisition here: Acquired Philips P800 mini computer systems.