From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: tuhs-bounces@minnie.tuhs.org X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, LOTS_OF_MONEY,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.1 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id ebd558a2 for ; Fri, 29 Jun 2018 18:13:14 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id B896BA1B14; Sat, 30 Jun 2018 04:13:13 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 4A8B7A1849; Sat, 30 Jun 2018 04:13:07 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 3953AA1849; Sat, 30 Jun 2018 04:13:06 +1000 (AEST) Received: from hacklheber.piermont.com (hacklheber.piermont.com [166.84.7.14]) by minnie.tuhs.org (Postfix) with ESMTPS id C0594A1815 for ; Sat, 30 Jun 2018 04:13:05 +1000 (AEST) Received: from snark.cb.piermont.com (localhost [127.0.0.1]) by hacklheber.piermont.com (Postfix) with ESMTP id CD9D711B; Fri, 29 Jun 2018 14:13:04 -0400 (EDT) Received: from jabberwock.cb.piermont.com (jabberwock.cb.piermont.com [10.160.2.107]) by snark.cb.piermont.com (Postfix) with ESMTP id ACF9E2DED82; Fri, 29 Jun 2018 14:13:04 -0400 (EDT) Date: Fri, 29 Jun 2018 14:13:04 -0400 From: "Perry E. Metzger" To: "Steve Simon" Message-ID: <20180629141304.4f10ed7f@jabberwock.cb.piermont.com> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [TUHS] Faster cpus at any cost X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tuhs@minnie.tuhs.org Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" On Fri, 29 Jun 2018 09:51:55 +0100 "Steve Simon" wrote: > I know this is a dangerous game to play, but what of the future? > > I am intrigued by the idea of true optical computers, > perhaps the $10M super-computer will return? One problem with optical is feature size. Even ultraviolet 200nm light waves are pretty big compared to the feature size we now have in the best chips (which is under 10nm at this point, though it will soon stall out.) If you want EM waves that are close to the size of current features, you're in the range of X-rays and aren't going to have an easy time manipulating them. All that said, a different kind of gedankenexperiment: Say you wanted to store data as densely as possible. Lets ignore how you would manage to read it and consider things on the same order of magnitude of "as dense as we're going to get". If you stored 1s and 0s as C12 and C13 atoms in a diamond lattice, you get about 1.75e23 bits per cc, or about 12 zettabytes per cc. (Someone should check my math.) I think it might be hard to do more than an order of magnitude better than that. So, that's a crazy amount of storage, but it looks like a pretty strong limit. > GPUs have definitely taken over in some areas - even where > SIMD would not seem a good fit. My previous employer does motion > estimation of realtime video and has moved from custom electronics > and FPGAs to using off the shelf GPUs in PCs. Not surprised to hear. They're kind of everywhere at this point, especially in scientific computation. Perry -- Perry E. Metzger perry@piermont.com