Not to mention power problems! But I have the feeling
that's a
bit small! Nothing on the scale of the Pentium II has ever been
achieved with transistors, never mind relays, and I'm sure they
tried. For example, it would be possible to place transistors at
1 per cubic inch, and have the cool adequately, but it's clearly
never been attempted, because if it were, there would be boxes
to plug into a PC XT to get Pentium II speeds.
I think CDC and IBM did a pretty good job in the mid to late 1960s with
thier mainframes. CDC used extremely tight packed circuit boards, but
fairly standard transistor packages, and manages to get a pretty
respectable performance from their 6000 series. IBM also did a pretty good
job with the classic S/360s. They managed to really pack the things in,
mounting the transistor dies directly to the ceramic "circuit boards"
inside the SLTs (those aluminum covered square packages).
I really do not know how many transistors went into those big bits of
iron, but it certainly was a great deal. A million may not be too far off.
William Donzelli
william(a)ans.net