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Manufacturer: Norsk Data
Form Factor: minicomputer
Word Size: 32 bit
Physical Address Size: 4 megabytes

The NORD-50 computer system is a completely integrated system of NORD-10/S and NORD-50 CPUs. The I/O system, file system and operating system are common to both processors.

The NORD-50 CPU was used in the ND 1100/S, ND 1200/S, ND 1300/S and ND 1400/S systems.

The NORD-50 CPU is designed to be a fast floating point processor which is a total slave to the NORD-10/S.

NORD-50 does not have an I/O system or interrupt system by itself, all I/O is done through the NORD-10/S which submits jobs to NORD-50 for execution in batches. The NORD-10 acts as a system supervisor running the operating system SINTRAN III/VS and the NORD-50 monitor.

In a NORD-50 computer system, the NORD-10/S has the following functions:

  • Supervision and synchronization of the NORD-50s in the system.
  • Running the operating system, SINTRAN III.
  • Generating NORD-50 executable machine code via NORD-50 assembler or FORTRAN compiler.
  • Being the I/O system for the NORD-50s performing I/O transfer to / from the NORD-50 memory.

The NORD-50s in the system perform execution of instructions with data supplied through the NORD-10/S I/O system from byte oriented devices such as terminals, general DMA devices such as disks and magnetic tapes, the universal DMA interface, and special high-speed DMA channels connected directly to ports in the multi-port memory system.

The NORD-50 can use multi-port shared and private memory and also static high-speed, private memory for frequently used code and data.

The NORD-50s themselves do not perform any tasks except for running the application programs.

The slave processor NORD-50 is activated by the NORD-10/S and NORD-50 executes programs in parallel with the activities in NORD-10/S. The NORD-10/S is interrupted when the NORD-50 comes to an end of its tasks.

To the NORD-10 the NORD-50 looks like any other device and is controlled via standard IOX instructions.


The NORD-50 CPU has a word length of 32 bits.

There are a number of registers in the NORD-50 CPU.

  • 64 general data registers with register 0 always containing zero.
  • The 64 general registers can be combined in pairs as 32 64 bit floating point registers.
  • The lower 16 registers can be used as base or index registers for addressing.

Address space

The NORD-50 has 4 megabytes physical address space.

Circuit boards

Main registers and arithmetic, communication registers NORD-10/NORD-50, memory address and data lines, line drivers for external arithmetic are organised on three different boads, each handling four bits:

  • 1501 Address Arithmetic
  • 1502 Register
  • 1503 Arithmetic Buffer

The 32 bit CPU uses eight of each board, making a total of 24 boards.

The timing and control section of the CPU uses eight different boards:

  • 1500 NORD-50 I/O Control
  • 1504 NORD-50 Controller
  • 1505 Register Address
  • 1506 Cycle Counter
  • 1507 Arithmetic Control
  • 1508 Chip Select
  • 1510 Instruction Control
  • 1519 Timing Control