Article 1235 of alt.sys.pdp10: Path: shellx.best.com!news1.best.com!sgigate.sgi.com!swrinde!howland.reston.ans.net!news.sprintlink.net!news1.cris.com!news From: Dick Maliska Newsgroups: alt.sys.pdp10 Subject: Re: Home grown Hardware diags Date: 20 Oct 1995 12:06:57 GMT Organization: Countryside Software Services Lines: 48 Message-ID: <4683d1$rpl@spectator.cris.com> References: <45hg1k$8q@www.uno.edu> <45j703$3qq@newsbf02.news.aol.com> <1995Oct18.120931.19272@indyvax.iupui.edu> NNTP-Posting-Host: crc2-fddi.cris.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 1.2 (Windows; U; 16bit) mwood@indyvax.iupui.edu (Mark H. Wood) wrote: >In article , hedley@netcom.com (Hedley Rainnie) writes: >> Eric Smith (eric@goonsquad.spies.com) wrote: >> : In article <45j703$3qq@newsbf02.news.aol.com> jmfbah@aol.com (JMFBAH) writes: >> : > That reminds me of a fixed head disk that was used for swapping (could it >> : > have been a Burroughs?) on a 48K KA system. There were ways to cause it >> : > to walk across the floor to the other side of the room. >> >> : A *FIXED*HEAD* disk? What could the software do to make it move? >> >> Didn't the Illiac IV have fixed head disks? They would have a head >> dedicated to a track for fast roll in/roll out. > >Yeah, we know how the FHx drives worked, but the question was how could >software make it walk across the floor if there was no moving access mechanism? >The disk spins, and the CPU selects a head to listen to, but the only moving >part is the platter itself, which just rotates. Ditto the drum unit (was that >an RC10, or is my memory even worse than I imagine?). >-- >Mark H. Wood, Lead Systems Programmer +1 317 274 0749 [@disclaimer@] >Internet: MWOOD@INDYVAX.IUPUI.EDU BITNET: MWOOD@INDYVAX >You are in a twisty little maze of hyperlinks, all useless. Mark, your memory is not THAT bad but a slight error. The RC10 was the the controller for the RD10 (Burroughs disk) and the RM10 (Bryant Drum), The RC10 also required a data channel called the &*10 (DF10 - as my failing memory recalls). The RM10 had an interesting quirk about it that I have to share; As the drum would "spin up", that is actually what it did. When it finally got up to speed the drum (actually a cone) had moved up to the heads. This was not noticeable by anyone until the unit powered down. When the drum nearly stopped spinning there would be a noticeable "thud" when the drum actually dropped away from the heads. This first time this happened, it was a bit scary because it was loud enough to sound serious. -- Regards, Dick Maliska (Rmaliska@cris.com) Ex Digitoid and Diagnostic Engineer COUNTRYSIDE SOFTWARE SERVICES. (508) 692-3124 Hardware/Software Support, Networking and Application Development. (Snail Mail: 183 Concord Road; Westford, MA 01886) "Rainbows are just to look at, not to really understand."