From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 9FCD31381F3 for ; Tue, 18 Dec 2012 14:10:20 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 241EF21C0FF; Tue, 18 Dec 2012 14:10:04 +0000 (UTC) Received: from mail-ob0-f173.google.com (mail-ob0-f173.google.com [209.85.214.173]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 867CB21C014 for ; Tue, 18 Dec 2012 14:08:54 +0000 (UTC) Received: by mail-ob0-f173.google.com with SMTP id xn12so630216obc.4 for ; Tue, 18 Dec 2012 06:08:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=zK4G1INcV9NGUGZVEiVDNra3O6kYnZOTVtFyEtiU4cs=; b=WvUWNctMFKl3U3E7AD5JYMipwgGh8k2kq1zj646UciEq9UH40ZW9GJQE3+ptcVa7Nx lkWZ/YFTvY4bUJEVJhdSsX21C6vWw7DobHJNh6BueVjKTVZxeRShKjYc2EXTsNcQR/NC nppFF1wuCS8BmjE1FmgjpHDEcpy2z6VeUE+BOi9vPAj5NwXJh8B8HDHFKtrmIivBhjAg rZicUbsqmQ5KM5AGPo/3vzHDpV6nWGo1wMYWA512RfnlfSixx7jiSz17qzUdVmvz3IbU eE5JpmrpF7AGut4UVdqFxrgekHkhbJvIXFVzdPlsAUGHLBWjR9biW7Q3QTK0uEVzQVrc wazg== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.182.226.103 with SMTP id rr7mr1558323obc.76.1355839733534; Tue, 18 Dec 2012 06:08:53 -0800 (PST) Received: by 10.76.20.243 with HTTP; Tue, 18 Dec 2012 06:08:53 -0800 (PST) In-Reply-To: <20121217104621.735bf43a@khamul.example.com> References: <50CB1942.3020900@gmail.com> <50CB4A3C.1030109@gmail.com> <50CB5406.7040404@gmail.com> <8738z7hgsa.fsf@ist.utl.pt> <20121216171043.71084070@khamul.example.com> <20121217104621.735bf43a@khamul.example.com> Date: Tue, 18 Dec 2012 09:08:53 -0500 Message-ID: Subject: Re: [gentoo-user] Re: Anyone switched to eudev yet? From: Michael Mol To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: e97aa37a-d43f-41c4-9b6e-d000e2940d4e X-Archives-Hash: 21bcab33099a57b024fc2344af045eed On Mon, Dec 17, 2012 at 3:46 AM, Alan McKinnon wrote: > On Mon, 17 Dec 2012 16:02:54 +0800 > Mark David Dumlao wrote: > >> > That was the original reason for having / and /usr separate, and it >> > dates back to the early 70s. The other reason that stems from that >> > time period is the size of disks we had back then - they were tiny >> > and often a minimal / was all that could really fit on the primary >> > system drive. >> >> I'm sorry, but I just can't let this one go. The reasons are >> backwards. The limitation in free space was the original reason [1] >> why / and /usr were separated. In fact, /usr was supposed to serve the >> same purpose as /home - it was originally a directory for users. It's >> only a quirk of history that served to keep most of the binaries in >> /usr when the home directories were moved elsewhere to /home. >> >> Long story short, Unix, too, has its share of old farts that are >> unwilling to embrace change at anything faster than a glacier's pace. >> Just ask the Plan 9 folks. >> >> [1] >> http://lists.busybox.net/pipermail/busybox/2010-December/074114.html > > Well fair enough. This stuff is becoming more myth than fact as less > and less people are around to remember how it really went. There may > even have been to-ing and fro-ing moving bits around till Ken and > Dennis settled on the eventual outcome in that post. > > Either way, we still agree. A separate /usr is, *for the most part*, a > tradition applied without much understanding of the reason (most > traditions are exactly like this). Most people do not actually need > it. > > Some people do need it and can clearly state why; I am not in that > group. Personally, that post on the busybox thread tends to infuriate me every time I see someone reference it. So, sure. The reason / and /usr were originally split is because their disks on the machine they were evolving this on were insufficient for the original layout. Let's look at that again, reduced: They split / and /usr because unforeseen operational requirements for a given system demanded it. And again, reduced: They did something because unforeseen operational requirements demanded it. This, right there, is the reason for separate / and /usr; operational requirements can place constraints on a system such that the initial configuration is no longer sufficient. It's the same reason you might have a separate /home. Or a separate /home/dad. Or a separate /var/cache. Every now and again, taking a folder and putting it on its own disk is the simplest, quickest and most straightforward way to solve a problem with the resources available. Now, why is /usr special? It's because it contains executable code the system might require while launching. But this is _only_ a problem if the code on /usr is required in order to mount /usr. What if /usr is on a raw disk? No special code needed there. What if /usr is on its own partition? No special code needed there. What if /usr is on hardware raid? No special code needed there. What if /usr is on RAID5 with version 0.9 metadata? No special code needed there. There are numerous circumstances where code on /usr should not be required to mount /usr. And circumstances can and have led to a separate /usr on numerous systems. Some people have set it up as read-only for security purposes. Some people have mounted it over NFS. Some people simply ran out of disk space and put it on a new disk. And, yeah, that can still happen; I've had to pull similar stunts on Windows in VMs (yay, junctions!) which grew larger than anticipated due to software updates. -- :wq