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The Nord-100 was a 16-bit minicomputer series made by Norsk Data, introduced in 1979. It shipped with the Sintran III operating system, and the architecture was based on, and backwards compatible with, the Nord-10 line.
The Nord-100 was originally named the Nord-10/M (M for Micro) as a bitsliced OEM processor. The board was laid out and finished and tested when they realized that the CPU was far faster than the Nord-10/S. The result was that all the marketing material for the new NORD-10/M was discarded, the board was rechristened the Nord-100, and extensively advertised as the successor of the Nord-10 line. Later, in an effort to internationalize their line, the machine was renamed ND-100.
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The ND-100 line used a custom processor, and like the PDP-11 line, the CPU decided the name of the computer.
- Nord-100/CE, Commercial Extended, with decimal arithmetic instructions (The decimal instruction set was later renamed CX)
- ND-110, incrementally improved ND-100
- ND-110/CX, an ND-110 with the decimal instructions.
- ND-120/CX, completely redesigned.
The ND-100 line was machine-instruction compatible with the Nord-10 line, except for some "extended instructions", all in supervisor mode, mostly used by the operating system. Like most processors of its time, the native bit grouping was octal, despite the 16-bit word length.
The ND-100 was frequently sold together with a memory management card, the MMS. The combined power use of these boards was 90 watts. These boards would usually occupy slots 2 and 3, for the CPU and MMS, respectively. Slot 1 was reserved for the Tracer, a hardware debugger system.
The CE stood for Commercial Extended. The processor was upgraded by replacing the microcode PROM.
It added instruction for decimal arithmetic and conversion, stack instructions, segment-change instructions used by the OS, a block move, test-and-set, and a read-without-cache instruction.
The ND-110 was an incremental improvement over the ND-100.
The ND-110 combined the Memory Management System and CPU, previously separate cards, on one board. The single CPU/MMS board was plugged into the memory management board slot, usually numbered 3. The power consumption was reduced from 90 watts to 60.
The ND-110 had three gate arrays:
- The Micro Instruction Controller, the MIC – also known as RMIC, for "Rask MIC" ("Speedy MIC"). It replaced three 74S482 sequencers and about 30 other ICs.
- The Arithmetical and Logical Unit gate array (ALU, also known as the "BUFALU"). Replaced four Am2901 bit-slice processors, and some additional registers like the data bus register the general purpose register, and the internal register block.
- The Micro Address Controller (The MAC, also called RMAC, for "Rask MAC" ("Speedy MAC"). It implemented hardware address arithmetic, which in the ND-100 had been done in microcode.
In addition to the macro-instruction cache memory also found in the ND-100, the ND-110 had a unique implementation of cache memory on the micro-instruction level. The step known as mapping in the ND-100 was then avoided because the first micro-instruction word of a macro-instruction was written into the control store cache.
Unlike the ND-100 CPU, it handled synchronous interrupts as traps, similar to how it was handled by the ND-500.
The CPU clock and the bus arbitration network were implemented using 15ns PALs.
The main oscillator was a 39.3216 MHz crystal oscillator.
This was the ND-110 with the CX microcode PROM. The added instructions were the same as the /CE.
The ND-120 CPU was a complete reimplementation on an LSI chip (The so-called Delilah chip), and was originally intended to be sold as the ND-1000, to reflect the technology change, which paralleled the change from the ND-500 series to the ND-5000 (Codenamed Samson).
The Samson/Delilah naming scheme may reflect that around the time of the development of the ND-120, it was increasingly clear that the mixed 16/32-bit architecture was a bottleneck for the ND-500(0) architecture; Internal technical documentation used at Norsk Data for the Delilah chip has a drawing of a grinning woman with hair in her clenched fist.