ND-500¶
ND's 32-bit architecture. One design, four hardware generations, twenty model numbers.
| Introduced | 1981 |
| Type | Coprocessor architecture |
| Word length | 32-bit |
| Needs a host? | Yes - needs an ND-100 or ND-110 |
| Replaced | NORD-50 |
| Replaced by | - |
| Survivors | 42 on the machine list (7 dismantled, 35 unknown) |
The short version¶
A 32-bit supermini that cannot run on its own: an ND-100 or ND-110 sits beside it as the I/O processor, running SINTRAN III and doing all its input and output. ND's own reference manual defines the term that way.
It is best thought of as one architecture with four implementations - ND-500/1, ND-500/2, Samson and Rallar - sold under many model numbers. The manual covers the ND-500 and ND-5000 together and says so: "this manual is valid for both".
Its register set shows what it was built for: dedicated bases for local variables and records, a top-of-stack register with limit traps, and whole chapters of string instructions. This is a machine designed for compiled high-level languages - FORTRAN loops and COBOL string handling - not a scaled-up accumulator machine.
Specification¶
| Item | Value |
|---|---|
| Role | Compute processor. The ND-100/110 is the I/O processor |
| Addressing registers | P program counter, L subroutine link, B local variable base, R record base |
| Integer registers | I1-I4, 32-bit. Work on word, halfword, byte, bit and bit field |
| Floating registers | A1-A4, 32-bit, each extendable by E1-E4 into four 64-bit double-precision accumulators |
| Trap registers | ST status, plus own / child / mother trap enables and a modification mask, all 64-bit |
| Limit registers | TOS top of stack, LL and HL limit traps, THA trap handler address |
| Memory management | CED, CAD, PS, PSTP - microprogram only. Domains and process segments |
| Word size | "Word" means 32 bits. 16-bit ND-100 words are called halfwords |
| Host link | DMA over PCB 3022 - a bank of 16 IOX registers |
| Multiprocessor | Up to four CPUs sharing memory, sold as ND-580/n and ND-590n |
| Operating system | SINTRAN III, running on the host |
What was new¶
- ND's first 32-bit architecture that was a product line rather than one attached box.
- Built around procedure calls, records and strings - a language-oriented design.
- A trap system with mother/child inheritance.
- Up to four processors on shared memory.
Configurations¶
| Machine | What differs |
|---|---|
| ND-500/1 | First implementation - sold as ND-520, 540, 560 |
| ND-500/2 | Second implementation - sold as ND-510, 530, 550, 560, 570 |
| ND-505 | Cut-down export model for the CoCom embargo |
| ND-5000 | Third and fourth implementations - Samson and Rallar |
Sources¶
- Primary:
Reference-Manuals/ND-05.009.4 EN ND-500 Reference Manual.md - Secondary: ndwiki ND-500
Full context: MACHINE-TIMELINE.md.