NORD-12

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Differences between NORD-10 and NORD-12

This appendix is provided for those comparing NORD-10 with NORD-12.

1. Maximum memory size of the NORD-12 is 64K words. The Memory Management System option is not available for the NORD-12. With this option the maximum memory size for NORD-10 is 256K words.
2. The speed of the NORD-10 is 300 ns per micro-instruction for NORD-12 it is 500 ns per micro-instruction. This gives a 5/3 ratio for floating point, for all other instructions consult the NORD-10 and NORD-12 Reference Manuals.
3. Internal hardware error interrupts are not connected to level 14 on the NORD-12, and there is no IIE (Internal Interrupt Enable) register and no IIC (Internal Interrupt Code). However, on the NORD-12 it is possible to hardwire interrupts to level 14.
4. NORD-12 is only available with dynamic MOS memories (4096 bit/chip), while NORD-10 is offered with a range of different memories.
5. The rounding algorithm for floating point differs between NORD-10 and NORD-12. On NORD-12 there is no TG (Rounding) flip-flop in the Status Register (bit 1 in Status on NORD-1), and for NORD-12 all floating point results are truncated. On the NORD-10 the least significant bit in the result is forced to one if the result could not be exactly represented. For both the NORD-10 and NORD-12 all integers up to 2³²-1 will be exactly represented in floating point format, and all results to this limit will also be exact.
6. Only NORD-10 may have a NORD-1 Input/Output Channel as option.
7. The Memory Parity systems differs between NORD-10 and NORD-12. On NORD-10 TRA instructions are used for reading memory parity error information, on NORD-12 the parity mechanism is an Input/Output device which plugs into an I/O Slot. For both NORD-10 and NORD-12 Memory Parity is an option.
8. On NORD-10 the Bus Transceiver or Bus Extender is standard, this is an option on NORD-12.