martillo@cpoint.UUCP (Joacim Martillo) (01/17/89)
I was just told by former Sun employees that the latest version of NFS eliminates /dev/nd. I guess this makes sense for file system partitions, but I would think that for paging partitions using a raw network device would make sense. Is there anybody around who can clarify this issue?
ed@mtxinu.COM (Ed Gould) (01/19/89)
>I was just told by former Sun employees that the latest version >of NFS eliminates /dev/nd. I guess this makes sense for file >system partitions, but I would think that for paging partitions >using a raw network device would make sense. Is there anybody >around who can clarify this issue? That's correct. The new diskless code (we run diskless MicroVAXen with it) does not use ND. ND was a hack put together in a few hours to be able to run diskless machines before there was a reasonable protocol available. Running diskless without ND involves paging to a file on the server. With the BSD fast file system, this is acceptably efficient. The Sun people have stated that their performance goal for diskless NFS was to be as fast as a local SCSI disk. While I'm not entirely convinced that they met this goal, they at least came pretty close. -- Ed Gould mt Xinu, 2560 Ninth St., Berkeley, CA 94710 USA ed@mtxinu.COM +1 415 644 0146 "I'll fight them as a woman, not a lady. I'll fight them as an engineer."
liam@cs.qmc.ac.uk (William Roberts) (01/24/89)
In article <739@mtxinu.UUCP> ed@mtxinu.COM (Ed Gould) writes: >Running diskless without ND involves paging to a file on the server. >With the BSD fast file system, this is acceptably efficient. Bear in mind that program text is NOT swapped in Berkeley 4.2 (or SunOS 3.x, 4.0) so that when a page of the program needs to be reloaded into memory it is pulled back from the original file; this is the reason why you can't write into a program while it's being executed ("Text file busy"), unless of ocurse it's on a remote file system :-) This becomes annoying if you *do* have local disk, but are executing binaries from a remote file system. As for ND, it is interesting to note that the Project Athena system uses a "block server" for its root (and usr?) partitions, which is at the same level as ND and avoids the overheads incurred by accessing files through their inodes, but only for a read-only file system. -- William Roberts ARPA: liam@cs.qmc.ac.uk (gw: cs.ucl.edu) Queen Mary College UUCP: liam@qmc-cs.UUCP LONDON, UK Tel: 01-975 5250