Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!aglew From: aglew@oberon.crhc.uiuc.edu (Andy Glew) Newsgroups: comp.arch Subject: Re: Data Storage density questions Message-ID: Date: 30 Jul 90 19:52:43 GMT References: <2635@mindlink.UUCP> <10048@pt.cs.cmu.edu> Sender: usenet@ux1.cso.uiuc.edu (News) Organization: University of Illinois, Computer Systems Group Lines: 36 In-Reply-To: lindsay@MATHOM.GANDALF.CS.CMU.EDU's message of 30 Jul 90 15:43:45 GMT >Which reminds me, what ever happened to the idea of a "head stick", >i.e. many thin-film magnetic heads, fabricated onto a rigid bar? I >realize that head yields were awful at one time, and I realize that >disks used to be great big things. But now, surely, it's time to >think of tiny little head-per-track disks. I periodically ask disk engineer types about this. Usually the answer comes back "aeronautics". You don't just want many heads, you want many heads each flying very close to the disk. With a rigid bar you get a lever effect on the worst case separation => separations must be larger => weaker signals => ... I still have some hope that good signal processing might be able to compensate for some of this (ie. integrate several heads' signals under a filter to gain one track's signal). There are some disks that have multiple heads per arm, put my understanding is that each of these heads is independently suspended. -- Andy Glew, andy-glew@uiuc.edu Propaganda: UIUC runs the "ph" nameserver in conjunction with email. You can reach me at many reasonable combinations of my name and nicknames, including: andrew-forsyth-glew@uiuc.edu andy-glew@uiuc.edu sticky-glue@uiuc.edu and a few others. "ph" is a very nice thing which more USEnet sites should use. UIUC has ph wired into email and whois (-h garcon.cso.uiuc.edu). The nameserver and full documentation are available for anonymous ftp from uxc.cso.uiuc.edu, in the net/qi subdirectory.