[sdiy] IN your mind, what is ....

[Rainer Buchty]

> Zilog's Z-80 was yet another 8080 spinoff, basically, and it was everywhere
> in Sinclairs and such.
> IIRC, the progression went 4004 > 8008 > 8080 > Z-80 > 8085 > 8086 > 80186 >
> '286 > '386 > '486 > Pentium and Celeron.

Not entirely true, the Z80 is a "sidearm" of the 8080/8085; the Z80
features did not evolve into the 8086, which in term is not really a
direct offspring of the 8085 but rather started a new family. Just as the
68000 is not really an architectural successor to 6809.

The 80186 in term is basically a microcontroller built around the 8086,
i.e. containing timers and UART; it also introduced some new commands
(e.g. ENTER/LEAVE).

It is also noteworthy, that the Pentium I was the last classic CISC
machine. With the Pentium Pro (which then led to the Pentium II) those
CPUs just look like CISC to the progammer, but internally they are
completely different (depending on the generation either some sort of RISC
machine or VLIW).

> Further off topic, intel maintains 2 separate CPU design teams; they
> work on alternate generations in a game of R&D leapfrog (of course, they
> share information, too). Maybe this is why only IBM is keeping up with
> intel in the CPU race.

Plus, it's the money Intel can afford to pump into R&D. I remember a press
conference in Munich where Hans Geyer of Intel was asked if they fear the
competition with AMD (who had recent success with the K6 back then) and
his answer was something like "No, why? We put more money into research
than they [AMD] have revenues..."

> There will be pure analog DIY as long as parts are available. But this
> "digital stuff" is an increasing part of DIY.

One of the more interesting developments is that at some stage everybody
started to diss analog design, also in education. It was just not
fashionable anymore, somewhat tainted in the new, clean digital ages where
everyone could build machines from Lego parts ... erm ... 74xx TTL chips.

Then frequencies started to rise higher and higher and out of the sudden
all this analog wickednesses started to pop up again playing a major role
in digital design...

Rainer