Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!brutus.cs.uiuc.edu!lll-winken!uunet!sco!rosso
From: rosso@sco.COM (Ross Oliver)
Newsgroups: comp.unix.xenix
Subject: Re: (SCO) TCP/IP, NFS vs locking
Message-ID: <5488@viscous.sco.COM>
Date: 29 Aug 89 23:21:58 GMT
References: <193910@neabbs.UUCP> <118@mdi386.UUCP>
Sender: news@sco.COM
Reply-To: rosso@sco.com (Ross Oliver)
Organization: SCO Technical Support
Lines: 27

In article <118@mdi386.UUCP> bruce@mdi386.UUCP (Bruce A. McIntyre) writes:
>In article <193910@neabbs.UUCP>, richard@neabbs.UUCP (RICHARD RONTELTAP) writes:
>> In a recent issue of one of the popular computer magazines.
>  
>>> "Because NFS is stateless, it doesn't support locking directly.
>>> Locking is implemented using separate lock managers ..."
>  
>> Does this mean that NFS does *NOT* support standard System V locking?
>> Will I have to buy a new version of C-ISAM, or kludge around it with
>> a custom file-lock over a LAN, before using C-ISAM functions?
>
>Yes, it means that it does NOT support standard SysV locking.  but it
>does support it's own variation.

SCO NFS supports standard System V file locking (i.e. the lockf()
library function).  Locking is implemented using the Network Lock Manager
protocol, which is what the above magazine quotation is referring to.
One of our networking engineers adds this comment:

    It should be noted that that Network Lock Manager (NLM) protocol
    does not provide for deadlock detection, so programmers should
    handle this within their own code.  The NLM will handle deadlock
    detection for lock requests which are local, however.

Ross Oliver
Technical Support
The Santa Cruz Operation, Inc.