From mboxrd@z Thu Jan 1 00:00:00 1970 To: 9fans@cse.psu.edu Subject: Re: [9fans] 9P to 9P2000 migration path From: "rob pike" MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Message-Id: <20010128192407.7C8F3199EF@mail.cse.psu.edu> Date: Sun, 28 Jan 2001 14:23:48 -0500 Topicbox-Message-UUID: 53c14088-eac9-11e9-9e20-41e7f4b1d025 > What is the migration strategy for 9P to 9P2000? Is > there consideration given to operating a network in > mixed mode (9P/9P2000) and what it would take to > do so? Is there a provision for protocol versioning? A great deal of agonizing and very little decisiveness went into resolving this issue. The current situation is to have the physical (main, worm-based) file servers honor both protocols, but to have the CPU and terminal kernels talk only the new one (and of course old ones talk only the old one). Thus both old and new systems can coexist. We have a program that can be interposed into a conversation to let a new kernel talk to an old service, but translating client new protocol to server old protocol. This is sufficient, for example, to let the new kernel boot from the existing binary of disk/kfs. Over time, we will translate the applications to use the new protocol only. That sort of thing. The necessary hooks for protocol versioning is provided by the "version" message. -rob