Path: utzoo!mnetor!uunet!wa3wbu!john From: john@wa3wbu.UUCP (John Gayman) Newsgroups: comp.sys.ibm.pc Subject: Re: Hub ring on HD floppies Message-ID: <433@wa3wbu.UUCP> Date: 19 Dec 87 21:15:26 GMT References: <415@wa3wbu.UUCP> <3209@batcomputer.tn.cornell.edu> Organization: WA3WBU, Marysville,PA Lines: 40 Keywords: floppies Summary: here is an answer In article <3209@batcomputer.tn.cornell.edu>, dorin@batcomputer.tn.cornell.edu (Stewart Johnson) writes: > Here's my guess: The old full-height black faced ibm floppy drive has a hub > engagement mechanism that is a real monster masher. Bad design. Even with I received several replies to my inital question. The biggest opinion seemed to be that the HD floppies have no hub-ring so you can tell them from 360K floppies in bulk form. I'll admit, it'd be pretty hard to tell the difference without trying to format them. I had remembered reading something a while back about the HD drives being sensitive to hub configurations. But then again, you can put 360K floppies in a HD drive to read them and it doenst appear to cause the drive any harm. So I guess I can beleive that it's to tell them apart. Anyone with conflicting stories ? :-) > Now I have a question: I know that hard drives use heavy energy and give > off bunches of heat. But WHERE do they give off the heat FROM, the disk unit The controller gives off a very insignificant amount of heat. The majority of the heat comes from the disk drive itself. If you've ever taken your machine apart after having it run for many hours or a day (XT variety) you'd notice the hard disk drive is *very* warm. This is the reason that its recommended a dual hard disk XT have the drives side-by-side. I beleive it is normal for the hard disk to run warm. I've noticed the same thing on hard disks in mini's and mainframes. They must have adaquate ventilation though. This is also the reason that its important you let a new driver "warm up" a bit before doing a low-level format to allow its temperature to stabilize. Lets face it, the XT doesnt have the greatest cooling system. I used to notice mine getting quite warm on top after several hours operation. I do not notice the same on my AT, the AT has a much better air-flow and stays *much* cooler. TO get back at the original question ( :-)) the heat within the hard disk module comes from the positioning motor and sindle motor. John -- John Gayman, WA3WBU | UUCP: uunet!wa3wbu!john 1869 Valley Rd. | ARPA: wa3wbu!john@uunet.UU.NET Marysville, PA 17053 | Packet: WA3WBU @ AK3P