Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: Memory hierarchy
Message-ID: <3306@crdos1.crd.ge.COM>
Date: 2 Apr 91 14:46:17 GMT
References: <2845@shodha.enet.dec.com> <1998@kuling.UUCP> <2832@shodha.enet.dec.com> <1991Mar28.152952.18380@rice.edu> <00670398761@elgamy.RAIDERNET.COM> <-+EAGCE@xds13.ferranti.com>
Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen)
Organization: GE Corp R&D Center, Schenectady NY
Lines: 26

In article <-+EAGCE@xds13.ferranti.com> peter@ficc.ferranti.com (Peter da Silva) writes:

| How about magnetic disk-optical disk, as in things like the Epoch Infinite
| Storage server? A new level... between tape and disk, not between disk and
| RAM.

  Point taken, for any r/w optical format. 

  The problem is that the optical disks fall at a funny place in the
hierarchy. Typically the ration of cache to memory, memory to disk,
disk to tape is an order of magnitude in size, access time, and
cost/bit. Optical is not on that path in terms of size or cost, and with
new larger disks, neither are tapes. There is a real need for a large
backup medium right now.

  With PC and workstation disk going multi gigabyte at reasonable
prices, there is no acceptable way to back up. Whatever the hardware
costs, the labor of having someone changing media drives the price of
backup to the point where you can't afford to do the backups you should.

  I have faith in capitalism, there will be something better soon.

-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
        "Most of the VAX instructions are in microcode,
         but halt and no-op are in hardware for efficiency"