Re: [TUHS] VFS prior to 1984

[Arthur Krewat <krewat@kilonet.net>]

On 7/5/2020 10:43 AM, Larry McVoy wrote:
> So I've encountered lots of holes in NFS files where there shouldn't be
> any.  So it is/was a thing.  But that said, I can't remember a single
> case of encountering that on Sun's campus.  I don't know if my memory
> is failing me, but I do know that when I left Sun and started working
> with other NFS implementations, yeah, lots of problems.  Somehow Sun
> got it right where other people didn't.

I can say personally, since the early 90's on SunOS, I never ever saw 
this problem in a variety of environments. One being Nynex Science and 
Technology where I did a consulting stint. 800+ node Sun 3/4 SunOS 
workstation/server environment, basically everyone's desktop was a Sun 
workstation for email, documentation, whatever. Another being a defense 
contractor I was at for 7 years, they were all Sun for engineering 
workstations and servers.

There is one possibility I just thought of, and that's if the first 
write fails and then a context switch happens, if enough free space is 
made available before the next context switch back to the second write, 
I can see that being a problem ;)

As if you weren't already tired of my rambling... When it comes to 
non-Sun operating systems, all bets were off. They all (mostly) worked 
with their own kind. That usually wasn't the case when it came to 
cross-vendor support. Sun<->HP was not great, but that also may have 
been driver problems in the one instance I tried it for an extended 
period of time. Two instances at different customers of AIX<->Sun 
actually worked rather well. The YP integration was key.

The entire problem with "holey" files and NFS is certainly related to 
the usage type of the system in question. What was Sun doing? Email? 
Software development? Using a common NFS share for the compiler? And 
then copying their code up to a central location? Not a lot of 
sync/write/sync/write activity, unless object file generation is a lot 
of skipping around all over the place. ;)

art k.