Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!aglew From: aglew@crhc.uiuc.edu (Andy Glew) Newsgroups: comp.arch Subject: Re: CD-ROM documents (was Paperless Office) Message-ID: Date: 7 Dec 90 03:17:36 GMT References: <11191@pt.cs.cmu.edu> <00940487.15804140@KING.ENG.UMD.EDU> <28083@mimsy.umd.edu> <1990Nov29.162726.11411@mozart.amd.com> <11212@charm.UUCP> <2974@crdos1.crd.ge.COM> <1990Dec3.220850.18352@watdragon.waterloo.edu> Sender: news@ux1.cso.uiuc.edu (News) Organization: Center for Reliable and High-Performance Computing University of Illinois at Urbana Champaign Lines: 15 In-Reply-To: herrickd@iccgcc.decnet.ab.com's message of 6 Dec 90 14:35:23 GMT >> Why are CD-ROM seeks so slow? Is it related to the spiral tracking? > >The audio Compact Disk spec includes constant linear speed along the >spiral track that runs the entire length of the disk. The average >seek includes moving a significant distance along the radius of the >disk, requiring a noticable change in the rotational speed of the >disk. That average change in rotational speed is the critical path >factor in the half second seek time. Seems to me that the same techniques that are used to get constant linear density (as opposed to constant angualr density) on regular disks should apply. -- Andy Glew, a-glew@uiuc.edu [get ph nameserver from uxc.cso.uiuc.edu:net/qi] Brought to you by Super Global Mega Corp .com