From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 29 Sep 2002 15:50:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 29 Sep 2002 15:48:47 -0400 Received: from mailhost2-bcvloh.bcvloh.ameritech.net ([66.73.20.44]:64910 "EHLO mailhost.bcv2.ameritech.net") by vger.kernel.org with ESMTP id convert rfc822-to-8bit; Sun, 29 Sep 2002 15:48:14 -0400 Content-Type: text/plain; charset=US-ASCII From: james To: Jens Axboe , Linus Torvalds Subject: Re: v2.6 vs v3.0 Date: Sun, 29 Sep 2002 14:53:35 -0500 User-Agent: KMail/1.4.3 Cc: Ingo Molnar , Jeff Garzik , Larry Kessler , Alan Cox , linux-kernel mailing list , "Andrew V. Savochkin" , Rusty Russell , Richard J Moore References:

<20020929091539.GB1014@suse.de> In-Reply-To: <20020929091539.GB1014@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <200209291453.35096.jdickens@ameritech.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Upon thinking about 2.6 v3.0 argument, I think we may be looking at this version comparison in the wrong light, it is not wether we have come far enough from 2.4.x to make it 3.0 it is wether we have change enough from version 2.0.x. When I compare running linux 2.0.x to running what will be the next version we are looking at a completely different system. For example in v2.0 the only file system choices were ext2 or DOS, with a few others that wern't in wide spread use. where you created small partitions to keep fsck's fast, even if you had battery backup, you were still basicly limited to 8 gig file systems. Today we have ext2, ext3, reiserfs, JFS, XFS, in the last four, journaling capabilities. it is possible and expected have huge filesystems and patches exist to break the 2 terabyte file systems exist in various stages of testing. Not to mention we have LVM, and raid file systems, being used on desktop as well server systems. Networking has changed as well, we went from mostly 10mbit eternet cards and a few 100 mbit cards, to now having 100mbit ethernet as the base of home networking, not to mention gigabit ethernet, and ATM gaining popularity in the server market, while they are just drivers, the real shift of thinking comes in zero copy file transfer and a mature state of the art firewalling/routing/bridging etc. in NAT and iptables For video we changed from base VGA video text and X, to acellerated video processors not just in X, but in framebuffers used as consoles. We also have support for diverse set of buses, that change the way we think about our system, multiple bridges on PCI, USB v1 and v2, to firewire. I will let others more in the know in memory management, discuss the finer points of this one, but it is a major change, in 2.0 we just killed random programs when out of memory. today we make a slightly more educated guess as what to kill when we are out of memory, not to mention a just one base mix of address support, I think it was 2gig user and 2gig, Today we can choose, 1. 2, or 3 gig of kernel space. Large memory support in the Kernel , supporting 36bit memory accessing, That support more memory than I will ever see in the near future. we have changed from a System that barely supported smp with 2 processors with basicly one big kernel lock to a system with finely grained locks and semaphores and subsystem spinlocks, that has decent performance on 8+ cpu systems. Numa system surport also appeared since version 2.0.x In 2.0.0 we had a 15bit pid with a maximum of 1000 active ( i beleve it is less than this) today we have a 32+bit pid on the table with support of many more active processes. of couse we have numourous internal file systems that did not exist, tmpfs, devfs, etc..... and changed the way we all think about our systems. A prempted kernel, need I say more. well that is just a small list of the globals systems that change the way we think of linux. If we continue to justify major version changes based on change in minor version to minor version, can we expect linux 2.98,x in the future? In each minor version we rewrite one or two subsytems. And these take many months to plan, complete and test, so big enough change in a single minor version number to minor version may not be possible at the current size of this devolement effort, So yes we have come far enougth from v2.0.x to justify a version 3.0.x. If I was a marketing person I would call it linux 3.0.0 enterprize edition, if we can get LVM2, raid and break the 2 terabyte filesystem limit along with what we allready have accomplised. Just my opionion James