Why magnetic drums was/are worse than disks ?
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From: kus@free.net on 12 Oct 2006 12:45 Sorry, what is the reason(s) that magnetic drums became worse than magnetic disks ? More bad surface shape for some technology processes, more low packaging density (in comparison w/disk packs having multiple plates) or something other ? Yours Mikhail Kuzminsky Zelinsky Institute of Organci Chemistry Moscow
From: Nick Maclaren on 12 Oct 2006 12:51 In article <1160671559.072931.103380(a)e3g2000cwe.googlegroups.com>, "kus(a)free.net" <kus(a)free.net> writes: |> Sorry, |> what is the reason(s) that magnetic drums became worse than magnetic |> disks ? |> More bad surface shape for some technology processes, more low |> packaging density (in comparison w/disk packs having multiple plates) |> or something other ? Packaging density. In all other respects, they were better. Regards, Nick Maclaren.
From: Richard E Maine on 12 Oct 2006 12:59 kus(a)free.net <kus(a)free.net> wrote: > what is the reason(s) that magnetic drums became worse than magnetic > disks ? > More bad surface shape for some technology processes, more low > packaging density (in comparison w/disk packs having multiple plates) > or something other ? Well, I wasn't "there" at the time, but it isn't hard to construct some pretty good reasons. Can you imagine spinning a drum at 15,000 RPM? And while maintaining shape well enough to allow heads to float as closely above it as they do above today's disks? I'm no mechanical engineer, but I think I can see which shape is easier to maintain. There are probably other reasons as well, such as your packaging density (though early disk drives were awfully big also), but I bet physical stresses were an issue. -- Richard Maine | Good judgment comes from experience; email: my first.last at org.domain| experience comes from bad judgment. org: nasa, domain: gov | -- Mark Twain
From: Stephen Fuld on 12 Oct 2006 13:08 "Nick Maclaren" <nmm1(a)cus.cam.ac.uk> wrote in message news:eglrqs$jfn$1(a)gemini.csx.cam.ac.uk... > > In article <1160671559.072931.103380(a)e3g2000cwe.googlegroups.com>, > "kus(a)free.net" <kus(a)free.net> writes: > |> Sorry, > |> what is the reason(s) that magnetic drums became worse than magnetic > |> disks ? > |> More bad surface shape for some technology processes, more low > |> packaging density (in comparison w/disk packs having multiple plates) > |> or something other ? > > Packaging density. Absolutely. This was the big reason. > In all other respects, they were better. Well, one area that disk packs had (at least at first) that drums didn't was interchangability. That is, you could have more disk packs than drives and load the packs as needed, sort of like having more tape reels/cartridges than tape drives. This could give the illusion of more storage on-line than was really available. Of course, as technology progressed, this idea had to give way to increased density. -- - Stephen Fuld e-mail address disguised to prevent spam
From: Rick Jones on 12 Oct 2006 13:12
Richard E Maine <nospam(a)see.signature> wrote: > Well, I wasn't "there" at the time, but it isn't hard to construct > some pretty good reasons. Can you imagine spinning a drum at 15,000 > RPM? Make it solid and I guess you would have a pretty decent flywheel to keep the system powered for brief power interruptions :) Just watch-out if it ever broke loose from its housing... Spin-up times might not be all the pleasant short of a really powerful motor. rick jones -- Wisdom Teeth are impacted, people are affected by the effects of events. these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH... |