From owner-freebsd-stable Tue Mar 14 15:44:53 2000 Delivered-To: freebsd-stable@freebsd.org Received: from workhorse.iMach.com (workhorse.iMach.com [206.127.77.89]) by hub.freebsd.org (Postfix) with ESMTP id 20F8437B85B for ; Tue, 14 Mar 2000 15:44:49 -0800 (PST) (envelope-from forrestc@workhorse.iMach.com) Received: from localhost (forrestc@localhost) by workhorse.iMach.com (8.9.3/8.9.3) with ESMTP id QAA04238; Tue, 14 Mar 2000 16:41:46 -0700 (MST) Date: Tue, 14 Mar 2000 16:41:46 -0700 (MST) From: "Forrest W. Christian" To: Stephen Cc: "Charles N. Owens" , Ken Bolingbroke , freebsd-stable@FreeBSD.ORG, Peter Radcliffe Subject: Re: disk cloning (& a bit of picobsd) In-Reply-To: <20000314150815.A20664@visi.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, Mar 13, 2000 at 10:14:10AM -0500, Charles N. Owens wrote: > I also am curious as to why use of dd in this way is bad. Just my $0.02... "It Depends". First of all we're assuming a "modern" hard drive here which basically hides bad sectors from the os... If this isn't the case this opens the whole bad sector mapping can of worms. Depending on what you dd, you might find that interesting things happen. For example if you dd the entire disk (including partition tables, etc), everything will work great 100% of the time if the drive geometry (size, CYL, HD, SEC) is identical. If they differ, you may end up with some rather nasty weirdness such as inability to boot, corrupted data, etc. etc. etc. Along the same lines, if you dd a single partition you can experience weirdness if some parameter changes which the filesystem living on the partition to be consistent. So, maybe the short version of why someone could consider it "bad" to dd is that if you use something OTHER than dd, you generally have less concerns about corrupting a filesystem. FWIW, I do a LOT of picobsd stuff and ALWAYS use dd to copy floppies. Never have a problem. Then again a floppy is always 1.44MB - Forrest W. Christian (forrestc@imach.com) KD7EHZ ---------------------------------------------------------------------- iMach, Ltd., P.O. Box 5749, Helena, MT 59604 http://www.imach.com Solutions for your high-tech problems. (406)-442-6648 ---------------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message