26 Sep
2022
26 Sep
'22
3:45 p.m.
On Fri, Sep 23, 2022, 21:50 Ali via cctalk <cctalk(a)classiccmp.org> wrote:
I always thought the i960 was an upgrade to the i860
(sort of like i386 to
i486 upgrade). However, based on the info on wiki it seems as if the i960
actually came first and although a RISC chip it was in no way in the same
league as the i860. Anyone can clarify or verify this?
They're totally unrelated, except that they both came from Intel.
The i960 was the BiiN processor, stripped (in most versions) of the tagged
memory and capability architecture. The BiiN processor was an attempt to
keep the "good parts" of the iAPX 432, without the huge performance penalty
of the 432 as compared to "normal" processors (e.g., MC68000). So the i960
basically threw away the BiiN's vestiges of the 432, transforming it into a
"normal" processor. It was successful in embedded applications, such as
laser printer.
I don't know the development history of the i860, but it is not similar in
any way to the i960. There were some Unix workstations based on the i960,
but many sources claim that it didn't meet expectations because of the
exposed pipeline (making compiler development difficult), imprecise
exceptions, and expensive context switching.