comp.arch Google Group

Re: Computer on a chip...

acol...@efunct.com (mac) — Mon, 20 May 2013 17:55:29 UT

You don't really need the same delay. Just the same delay modulo the clock
period. The latter is usually bounded

--
mac the naïf

Re: Computer on a chip...

r...@127.0.0.1 (Noob) — Mon, 20 May 2013 11:15:26 UT

Noob wrote:

I just came across RWT's take on the subject:

[link]

RWT wrote:

Regards.

Call for Papers: World Congress on Engineering and Computer Science WCECS 2013

iaeng_imecs_wce_wcec...@iaeng.org (iaeng_imecs_wce_wcecs_e) — Mon, 20 May 2013 08:20:27 UT

Call for Papers: World Congress on Engineering and Computer Science
WCECS 2013

CFP: World Congress on Engineering and Computer Science WCECS 2013
Draft Paper Submission Deadline: 2 July, 2013
Camera-Ready Papers Due & Registration Deadline: 30 July, 2013
WCECS 2013: San Francisco, USA, 23-25 October, 2013

Re: Computer on a chip...

i...@ootbcomp.com (Ivan Godard) — Sat, 18 May 2013 19:24:59 UT

The boundary between a signal on a wire and RF in a waveguide blurs,
even in old tech. On the B6500 circa 1970, the Gardner-Denver backplanes
that the cards fit into (roughly five flip-flops per card) were subject
to spurious ringing; frequency and hot spot varied from machine to
machine due to parts tolerance variation. Jake Vigil, the brilliant

Re: Computer on a chip...

mitchal...@aol.com (MitchAlsup) — Sat, 18 May 2013 18:51:03 UT

I used to make a joke about just putting the entire chip inside a magnetron
and sticking a wire up everywhere you wanted a clock signal.

Mitch

Re: Computer on a chip...

twom...@chiark.greenend.org.uk (Thomas Womack) — Sat, 18 May 2013 16:28:21 UT

In article <4dfep8hn5ecppfmbl93ih4nd1308e 4g...@4ax.com>,

We already have 2GB of on-package RAM for some cellphone apps, though
that's BGA-on-BGA mounting and no faster than contemporary PC main
memory.

[link]
is one you can get off the shelf for a fairly trivial sum.

Re: Computer on a chip...

colin_paul_glos...@acm.org (Paul Colin de Gloucester) — Sat, 18 May 2013 14:01:57 UT

On May 14th, 2013, UnixRun...@GMail.com sent:

You might enjoy reading the SoC (System-on-a-Chip) literature.

Re: Computer on a chip...

jsav...@ecn.ab.ca (Quadibloc) — Sat, 18 May 2013 11:05:19 UT

Well, if I wanted to transmit a clock signal to every part of a chip
with the same delay wherever it is used, I would be able to solve that
problem by using a trace that looked like little versions of the
letter H on the points of larger versions...

A curve like that for the flow of liquid inside a heat sink would also

Re: Computer on a chip...

robertwess...@yahoo.com (Robert Wessel) — Sat, 18 May 2013 08:56:19 UT

On Fri, 17 May 2013 17:25:17 -0700, "Chris M. Thomasson"

I basically agree - some amount of local memory (but still globally
visible and cache coherent) that is significantly faster than the
global memory would be a significant performance boost. Most OS's are
already NUMA aware, so tweaking them to improve page placement to take

Re: Computer on a chip...

n...@spam.invalid (Chris M. Thomasson) — Sat, 18 May 2013 00:25:17 UT

On Fri, 17 May 2013 13:24:47 -0700, "Chris M. Thomasson"

I was thinking along the lines of the 8GB of memory being directly
integrated with
the 2 processors such that the main 8gb "local" memory and its CPU's are
one...

Literally a fraction of a millimeter/nanometer away. 3d stacked perhaps.

Re: Computer on a chip...

robertwess...@yahoo.com (Robert Wessel) — Fri, 17 May 2013 22:27:45 UT

On Fri, 17 May 2013 13:24:47 -0700, "Chris M. Thomasson"

That's basically the "book" design IBM uses on mainframes. Current
mainframes can hold up to four books, each of which contains
processors (six multi-core chips, plus L4 cache in an MCM), memory
(all memory is on-book), and the top of the I/O hierarchy.

Re: Computer on a chip...

n...@spam.invalid (Chris M. Thomasson) — Fri, 17 May 2013 20:24:47 UT

I have always wanted the chip makers to create their own memory and
try to directly integrate it with several multi-core processors.

Can you directly integrate, say 8GB of memory and 2 multi-core processors
on a pluggable board? The motherboard would have high-speed bays for
these boards and several processors dedicated to system work like

Re: Computer on a chip...

exoph...@gmail.com — Fri, 17 May 2013 16:14:01 UT

It's package on package. Two separate packages on top of each other. Not really
a single package, although I guess you could look at it that way if you purchase
the SoC and RAM already soldered together.

The memory package itself does have multiple stacked dies to achieve the
necessary density and interface width. There have even been combo chips that

Re: Computer on a chip...

jsav...@ecn.ab.ca (Quadibloc) — Fri, 17 May 2013 11:16:17 UT

That is true enough. Even there, though, history records many failed
attempts at things like "wafer-scale technology".

It is true caches have limitations and overhead. I would be very
pleased to have a big chip which not only has all the memory on the
chip, but, say, a 4,096-bit-wide path between the memory and the CPU.

Re: Fractal heat transfer...

n...@spam.invalid (Chris M. Thomasson) — Thu, 16 May 2013 23:36:53 UT

[link]