Harvard vs. vonNeuman

From: Andy Holt <andyh_at_andyh-rayleigh.freeserve.co.uk>
Date: Wed Sep 29 01:19:14 2004

> That machine had an instruction to execute an instruction that was held
> in a register! ...

Another set of memories from vaious 3rd gen machines ...

All three of ICT 1900, IBM 360, Honeywell Level 66 (=6000) have instructions
to obey the instruction at <memory address> which, at the time they were
designed, must have seemed a way of getting the benefits of
self-modification without the problems.

IBM's EX and ICT's OBEY both were simple (indexed) instructions - Honeywell,
of course, also did something* too clever to the target instruction.

* I forget what ... but then I only wrote two small modules in assembler for
our L66 - everything else I did on that machine was either in Fortran or B.

Received on Wed Sep 29 2004 - 01:19:14 BST

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