Path: utzoo!utgpu!attcan!uunet!husc6!rutgers!rochester!pt.cs.cmu.edu!k.gp.cs.cmu.edu!lindsay From: lindsay@k.gp.cs.cmu.edu (Donald Lindsay) Newsgroups: comp.arch Subject: Re: memory speed & futurology Message-ID: <3162@pt.cs.cmu.edu> Date: 29 Sep 88 03:46:14 GMT References: <2179@ditmela.oz> <2220001@hpausla.HP.COM> Sender: netnews@pt.cs.cmu.edu Organization: Carnegie-Mellon University, CS/RI Lines: 16 In article <2220001@hpausla.HP.COM> cjh@hpausla.HP.COM (Clifford Heath) writes: >> It would seem that the access time on hard or optical disks is >> limited by rotational speed in the long run. >Given the (perhaps almost) unlimited density of optical disks, the >limiting factor on rotational speed is the speed of the encoder/decoder. >If you want to spin a disk with 1 million bits/track at 1000 >revs/second, you've got to detect that information at 1Gbit/second. I would say (from under my futurology hat) that it's basically silly to have moving objects. We want to scan read/write beam[s] across unmoving media. Of course, a disc is an inefficient shape: a rectangle has more area. Also, it can't be too small, or people will lose them. I'd say that a credit card has field-tested human factors. It would have to hold at least a gigabyte, since we wouldn't want to split encyclopedias onto two cards. -- Don lindsay@k.gp.cs.cmu.edu CMU Computer Science