From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id bc4f7a8e for ; Thu, 11 Apr 2019 16:35:51 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 5338494ED4; Fri, 12 Apr 2019 02:35:50 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 6475794926; Fri, 12 Apr 2019 02:35:22 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 2E57994926; Fri, 12 Apr 2019 02:35:20 +1000 (AEST) X-Greylist: delayed 2284 seconds by postgrey-1.36 at minnie.tuhs.org; Fri, 12 Apr 2019 02:35:19 AEST Received: from loire.is.ed.ac.uk (loire.is.ed.ac.uk [129.215.16.10]) by minnie.tuhs.org (Postfix) with ESMTPS id 29EAD94925 for ; Fri, 12 Apr 2019 02:35:18 +1000 (AEST) Received: from crunchie.inf.ed.ac.uk (crunchie.inf.ed.ac.uk [129.215.202.41]) by loire.is.ed.ac.uk (8.14.7/8.14.7) with ESMTP id x3BFv8pM018624 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 11 Apr 2019 16:57:08 +0100 Received: from macaroni.inf.ed.ac.uk (macaroni.inf.ed.ac.uk [129.215.197.42]) by crunchie.inf.ed.ac.uk (8.14.7/8.14.7) with ESMTP id x3BFv7xs008189; Thu, 11 Apr 2019 16:57:07 +0100 Received: by macaroni.inf.ed.ac.uk (Postfix, from userid 26013) id 8791B255ADDC; Thu, 11 Apr 2019 16:57:48 +0100 (BST) From: Richard Tobin To: "Erik E. Fair" , The Eunuchs Hysterical Society In-Reply-To: Erik E. Fair's message of Wed, 10 Apr 2019 19:37:05 -0700 X-Mailer: Ream 5.1.51-richard-mac Message-Id: <20190411155748.8791B255ADDC@macaroni.inf.ed.ac.uk> Date: Thu, 11 Apr 2019 16:57:48 +0100 (BST) X-Edinburgh-Scanned: at loire.is.ed.ac.uk with MIMEDefang 2.84, Sophie, Sophos Anti-Virus, Clam AntiVirus Content-Type: text/plain MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 129.215.16.10 Subject: Re: [TUHS] Unix filesystem semantics history - files with holes X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" > When did the Unix filesystem add the semantics for "files with holes" (large, > sparse files)? It was there in the first edition: https://www.bell-labs.com/usr/dmr/www/pdfs/man51.pdf The FILE SYSTEM (V) man page includes a last paragraph identical to that of FILSYS (V) in seventh edition: If block b in a file exists, it is not necessary that all blocks less than b exist. A zero block number either in the address words of the the i-node or in an indirect block indicates that the corresponding block has never been allocated. Such a missing block reads as if it contained all zero words. The first edition indirect blocks were a bit different though: if the file was bigger than 8 blocks (4kB), all the blocks in the inode were (singly) indirect. -- Richard -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.