1.4.1.8 - Norsk Data hardware - ND-5000

324715 - PCB 5615 - Samson Additional Arithmetic Processor (AAP) module

Description

A baby module for the Samson CPU.
An additional arithmetic processor, speeding up integer and floating point arithmetic.
This module has a nicely designed LSI chip with the Norsk Data logo. It is visible on the ND-320002 but unfortunately hidden under the IDAC module on the ND-320003 CPU.
The chip (FPU) is designed by ND and produced by Weitek.
Ole Christian Bendixen
Steinar Forsmo
Bjørn Solberg
Torstein Gleditsch
13. nov. 1990: Me and a colleague were at a customer site, debugging Sibas.
Sibas runs perfectly all day but crashed in the nightly verify.
The reported error was: Status -4; Realm header damaged.
SIBR-DBM read the whole database file into memory and then calculated the memory offset where each realm header should be found.
The ND-IMU chip was doing the integer address arithmetic but got it wrong :-(
The expression was quite simple: 11400B * 2B * 1000B with the expected result 23000000B.
Unfortunately the ND-IMU presented the wrong memory address 21000000B where no realm header could be found and SIBR-DBM crashed.
The ND-5000 CPU was replaced in the customer's computer and has been working perfectly ever since.
Back at the ND repair center we retest the ND-5000 CPU to confirm that it still failed, replaced the ND-IMU chip and voila.
I have the actual faulty ND-IMU chip as a souvenir for serious debugging.
ND-320001; ND-5200 systems: Not present.
ND-320002; ND-5400/5500/5700 systems: Found on the 2. layer of baby modules.
ND-320003; ND-5800/5900 systems: Found on the 2. layer of baby modules.
Print: A1 ECO: 3
PCB size 95 x 183 mm, x layers
Release date 19. Oct. 1988