Path: utzoo!mnetor!uunet!husc6!hao!oddjob!mimsy!umd5!ames!sdcsvax!nosc!humu!uhmanoa!uhccux!cm450s02
From: cm450s02@uhccux.UUCP (Jeff T. Segawa)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Hub ring on HD floppies
Message-ID: <1345@uhccux.UUCP>
Date: 18 Dec 87 09:59:44 GMT
References: <415@wa3wbu.UUCP> <3209@batcomputer.tn.cornell.edu>
Reply-To: cm450s02@uhccux.UUCP (Jeff T. Segawa)
Organization: U. of Hawaii, Manoa (Honolulu)
Lines: 26
Keywords: floppies

In article <3209@batcomputer.tn.cornell.edu> dorin@tcgould.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
>hub reinforcement rings it has tweeked alot of precious floppies. 
>
I didn't catch the beginning of this dicussion, but is anyone trying
to use high density floppies in an old 360K drive? (the H.D. floppies
I've seen do not use the reinforcing ring). If so, I'm not surprised if
you're seeing lot of "Error reading drive A: Abort, Retry, Ignore?"  
messages. Not only will some of those drives chew up the center of the
disk, but I don't think the magnetic media itself can be written to
reliably w/anything but a high density drive. I figured this out after
a few frustrating hours.

>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
>or the controller? 

Can't say for sure in the case of an IBM, but with my Mac II, the entire
cast aluminum structure of the Seagate drive gets warm. Can't find any
especially hot spot, though. None of the chips on the motherboard 
(including the SCSI chip) seems to get more than slightly warm, either.
I also used to have a SCSI card for IBMs, and I don't recall seeing any
of the parts heavily heatsinked, so I'd suspect that the drive itself is
the biggest source of heat, at least in SCSI systems.