From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: Date: Mon, 12 Jan 2009 11:06:24 -0800 From: "Russ Cox" To: "Fans of the OS Plan 9 from Bell Labs" <9fans@9fans.net> Subject: Re: [9fans] Quick question on fossil In-Reply-To: <1231783995.6916.162.camel@goose.sun.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1231783995.6916.162.camel@goose.sun.com> Topicbox-Message-UUID: 7ffbbd6c-ead4-11e9-9d60-3106f5b1d025 On Mon, Jan 12, 2009 at 10:13 AM, Roman V. Shaposhnik wrote: > I'm trying to read up on fossil implementation so > that I can sustain an intelligent conversation with > Andrey ;-) > > Now, the paper "Fossil, an Archival File Server" is > pretty good, but here's one simple question that > I can't find an answer to: there's a pointer to > the root of the filesystem block from the Super. > But what is the data structure that is expected > to reside in that block? I thought it was VtRoot, > but looking at a hexdump of the fossil file -- it > doesn't look like one. Super.active is the block number of a VtDirType block: a block containing a few (I think 3) VtEntry structs. VtRoot is the top of a vac archive. it too contains a pointer to a block containing a few VtEntry structs. you could think of VtRoot as the vac equivalent of fossil's Super. if you cd /sys/src/cmd/fossil mk 8.view 8.view /dev/sdC0/fossil you should get a graphical file system data structure browser, though since it is not part of the default build it may not need some work to make it build again. russ