Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!linus!encore!fay From: fay@encore.UUCP (Peter Fay) Newsgroups: comp.society.futures Subject: Re: 500MB/sec is only local, I think... Message-ID: <2216@encore.UUCP> Date: Mon, 23-Nov-87 14:20:29 EST Article-I.D.: encore.2216 Posted: Mon Nov 23 14:20:29 1987 Date-Received: Thu, 26-Nov-87 06:24:26 EST References: <19211@yale-celray.yale.UUCP> <8711201132.AA03014@hop.toad.com> <871@pbhyc.UUCP> <282@erc3bb.UUCP> Reply-To: fay@encore.UUCP (Peter Fay) Organization: Encore Computer Corp, Marlboro, MA Lines: 48 In article <282@erc3bb.UUCP> netnews@erc3bb.UUCP (Network_News) writes: >In article <8711201132.AA03014@hop.toad.com> gnu@hoptoad.UUCP (John Gilmore) writes: >>I doubt that Bell intends to provide switched 500MB/sec cross-country >>bandwidth; you and everybody else can probably get 500MB/sec through >>your local central office, perhaps 50MB/sec through your local city, >>and maybe 5MB/sec cross-country. > >There are various fiber-to-the-home experiments going on, one is in >Hunters Creek, somewhere in Fla. Depending on coding, digital >full-motion video (i.e. cable TV) requires on the order of 100Mb/s. >This is the driving force behind offering services of 100-500Mb/s to >the individual user. In such a situation you may have a video >front-end at a central office that is then routed to the home's >thata want to receive it. [...] > >Avi Feldblum >AT&T <- given for identification purposes only > >Disclaimer: The above in no way represents the official position of AT&T This whole discussion assumes: 1. A "home" computer can (or will soon) receive data at this rate (as opposed to a TV). 2. A "home" computer can (or will soon) be able to put data on it's bus or store data at this rate. 3. A "home" computer can (or will soon) have enough secondary storage to store, say a few seconds of data (5 secs = 2.5 Gbytes). I have enough contact with fibre-optic data transmission in computers to know that the problem isn't the fibre-optic bandwidth at all. The problem is high-speed transceivers, high-speed buffering, and high memory and bus bandwidth, not to mention secondary storage. It can be done with ECL and high- speed static ram today, but the cost in implementing this and huge memory and secondary storage is daunting to a supercomputer, not to mention a home computer. If one wants to do this hypertext stuff (forgive me, but I'm still not really informed on this) without secondary storage, i.e., just download into memory, then the problem _still_ isn't fibre-optic bandwidth, but latency. Probably 10 Kbytes/sec. would be enough - how fast can you read (or look at graphics), anyway? All one needs is a display latency short enough not to be bothersome to the human reader. -- peter fay fay@multimax.arpa {allegra|compass|decvax|ihnp4|linus|necis|pur-ee|talcott}!encore!fay