Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!bu-cs!ccjap From: ccjap@bu-cs.BU.EDU (John Papadopoulos) Newsgroups: comp.arch Subject: Re: how fast could disks be (Mach 1) Message-ID: <12239@bu-cs.BU.EDU> Date: Mon, 24-Aug-87 18:49:54 EDT Article-I.D.: bu-cs.12239 Posted: Mon Aug 24 18:49:54 1987 Date-Received: Tue, 25-Aug-87 06:04:57 EDT References: <12191@amdahl.amdahl.com> <1189@k.gp.cs.cmu.edu> <2316@mmintl.UUCP> <1192@k.gp.cs.cmu.edu> Reply-To: ccjap@bu-it.UUCP (John Papadopoulos) Organization: Boston University, Office of Information Technology Lines: 36 Keywords: laser disk magneto optic phased array Several years ago when I used to work at the "Magneto-Optical Storage Lab" at BU, I was told about some work that had been done at Xerox (PARC?). They were working on a crystaline structure that could be used as a phased array for a laser. The structural (or optical properties) were modified by electric fields. I think they placed some large number of electrodes on four sides of a cube of the crystal and "modulated" the crystal so that the beam exited the crystal in a predictable direction. I think they were thinking of using for a laser printer mechanism. There are some problems though, such as thermal expansion and contraction of the crstal, "speed" of the crystal, and the voltages required (I think they were quite high). But then at a bit density of ~1 bit/1 micron^2... Given one of these beauties, you could use a small section of a planar thin film of magneto-optical material with the crystal suspended above it. One problem with this is that vertical recording is used in some of the more attractive magneto-optical mediums. This requires that the laser beam be nearly perpendicular to the plane of the medium. This limits the surface area to quite a small section. One way around this is to deposit the thin film on the inside of a hemisphere and place the cystal at the focal point of the hemisphere, thus giving a maximal amount of surface area. One thing that I thought would be neat would be to have planar magneto-optic memories and to lay a blank memory on top of a programmed one and somehow make a "photocopy" of the programmed one onto the blank. Now that I what I call fast backups! -John Papadopoulos Boston University