From owner-freebsd-hardware Tue Oct 15 10:28:40 1996 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id KAA22402 for hardware-outgoing; Tue, 15 Oct 1996 10:28:40 -0700 (PDT) Received: from Rigel.orionsys.com (root@rigel.orionsys.com [205.148.224.9]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id KAA22396 for ; Tue, 15 Oct 1996 10:28:37 -0700 (PDT) Received: from localhost (dbabler@localhost) by Rigel.orionsys.com (8.7.6/8.6.9) with SMTP id KAA20085 for ; Tue, 15 Oct 1996 10:28:36 -0700 (PDT) Date: Tue, 15 Oct 1996 10:28:35 -0700 (PDT) From: Dave Babler To: freebsd-hardware@freebsd.org Subject: Re: sticky drives (was: your mail) In-Reply-To: <199610142244.PAA14956@GndRsh.aac.dev.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-hardware@freebsd.org X-Loop: FreeBSD.org Precedence: bulk On Mon, 14 Oct 1996, Rodney W. Grimes wrote: > > On Mon, 14 Oct 1996, Rodney W. Grimes wrote: > > > > > > This is extremely dangerous, BTW. When you take the drive out of the > > > > freezer, condensation may form on the platters as the drive heats up. > > > > Conversely, frost may form on the platters as the drive drops below freezing. > > > > > Isn't the chamber where the platters reside hermetically sealed? If so, > > how would moisture be there to condense in the first place? > > They are not hermetically sealed, they have a bidirection presure release > and filter valve. Look very closely at your disk drives. If they did > not do this (and the tried) the cases would blow apart when ship via > unpressearized air freight at someplace close to 22K feet MSL. > Given the normally controlled environment drives are supposed to operate in, that makes economic sense. I am surprised that an overpressure of 10-12 psi would rupture the case, though, on a volume that small, but then gain the castings that I've seen recently are quite thin to save material. -Dave