Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-lcc!ames!ucbcad!ucbvax!SUN.COM!nowicki From: nowicki@SUN.COM (Bill Nowicki) Newsgroups: mod.protocols.tcp-ip Subject: More NFS discussion Message-ID: <8612222136.AA06270@rose.sun.com> Date: Mon, 22-Dec-86 16:36:01 EST Article-I.D.: rose.8612222136.AA06270 Posted: Mon Dec 22 16:36:01 1986 Date-Received: Wed, 24-Dec-86 00:06:54 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 54 Approved: tcp-ip@sri-nic.arpa Development of real commercial network protocols is full of compromises, so it is not too suprising that some people think NFS is too Unix-like, while others think it is not Unix-like enough. Commercial MS-DOS and VMS products were demonstrated in February 1986, as well as many different Unix dialects, from PCs to a Cray-2. Let me try to correct some misconceptions: ..., NFS has no security or authentication. Authentication is done at the RPC level in a very open-ended manner. The default in the first implementation was to trust UIDs, since that is all that Unix provides. A scheme based on public-key encription has been discussed in papers (Goldberg and Taylor, Usenix conference 1985). ... it is assumed that there is a GLOBAL /etc/passwd file No, your implementation is free to have a simple table that maps these UIDs into whatever identifier that you use on your system. We found it easier to administer by keeping a unique number over as large a domain as possible. At some point you may have to translate between numbers that make sense in your domain, but having N x M translation tables is not practical to maintain. NFS uses very large UDP packets ... No, details of transport such as packet size are determined by both the client and server implementations. Slow machines like PCs use small transfer sizes, while faster machines such as Sun-3s take advantage of larger buffer sizes when available. So if a complete RPC and NFS can be fit into 64K, why is PC-NFS client only? Although I am not a PC user (luckily I have a Sun-3/75) my understanding is that MS-DOS (and the Mac, for that matter) can only run one program at a time. Therefore if you ran a server, then you could not run any other programs on that PC. We find in actual practice that people only put on floppies the files that they DO NOT want other people to get at - shared files can go on an NFS file system, and you use MS-DOS "COPY" commands to copy from one PC to another. Remember that Sun is an active member of the Corporation for Open Systems, and has ISO and FTAM (second DP version) products. NFS only makes many of the file-sharing problems visible - we need to continue research in this area. On the other hand, people with inter-operability questions should come to Uniforum in January 1987 and see it work for themselves. -- Bill Nowicki Sun Microsystems Above are personal opinions only, not official Sun positions.