From owner-cvs-all Fri May 7 0:57: 5 1999 Delivered-To: cvs-all@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id 8F65C14F3B; Fri, 7 May 1999 00:56:53 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id RAA28916; Fri, 7 May 1999 17:26:02 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id RAA41293; Fri, 7 May 1999 17:26:01 +0930 (CST) Date: Fri, 7 May 1999 17:26:00 +0930 From: Greg Lehey To: Bruce Evans Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org, phk@critter.freebsd.dk Subject: Re: cvs commit: src/sys/sys disk.h Message-ID: <19990507172600.T40359@freebie.lemis.com> References: <199905070738.RAA24019@godzilla.zeta.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <199905070738.RAA24019@godzilla.zeta.org.au>; from Bruce Evans on Fri, May 07, 1999 at 05:38:59PM +1000 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk On Friday, 7 May 1999 at 17:38:59 +1000, Bruce Evans wrote: >> Small is beautiful. One less header file is good. disk.h got >> superseded by nothing :-) > > Not true. Things in it got moved to disklabel.h and diskslice.h > "temporarily" since I didn't want to redesign the whole disk > subsystem. So you're really objecting to the fact that it was disk.h and not disk.h that went away? >> >> >> Novice hacker goes to guru. >> >> NH: Guru, I want to write a driver. >> G: RTFM. >> NH: Which FM? >> G: Read the source code of another driver, then WTFM. >> >> >> >> Guess which driver I read? > > NH: Which FD? > G: Depends on the type of driver. For disk drivers, read ahc source. NH: It's a kind of a virtual disk subsystem G: OK, look at ccd. >>> They all got used but a few (2 or 3) recently became unused and fewer >>> (1 or 2) haven't been used for some time. Countless generations of >>> driver authors should have known to not even look at most fields in >>> struct buf. Only vfs_bio and meta-drivers like ccd and vinum need to >>> know about them. >> >> If these countless generations have known about it, how come buf(9) is >> still so woefully inadequate? I had a crack at it a while back, but > > The existence of buf.9 is (almost) news to me (I vaguely remember the > commit mail for it). The driver interface to buffers is mostly very > old, so it is mostly documented in the 4.[3-4] BSD books. Right, I posted the Third Edition definition (20 January 1973) the other day. That's not the bit we're worried about. It's all the other cruft that's in there. I wondered about bp->b_proc, for example, but it's there in System V, so I decided it might mean something in BSD as well. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message