NFS open problem with RM/COBOL

[hansie]

Hi,

We are running RM/COBOL on a UNIX SVR4 system (NCR).
We have a mount to Netware 5.1 (Netware acts as the server).
I try to OPEN INPUT a file which resides on that Netware 5.1 volume.
The program waits for ever, trying to open the file, no IO-errors occurs ...
Under UNIX everything works fine, open with vi, writing etc.

Hope someone has a clue !

Thanks,
Hans

 

[k5tm]

Almost certainly there is something not quite right in your Netware settings. Have you tried an OPEN EXCLUSIVE INPUT to see if that works? Unlike vi and other things that you might have tried, RM/COBOL assumes file sharing and that is something that usually requires some special tweaking of Netware to get right. Maybe user xyzzy will have some ideas... Tom Morrison

 

[hansie]

Tom,

Thanks for your reply, can you explain to me, why no IO-ERROR occurs trying to open that specific file ?

Hans

 

[k5tm]

Hans,

The simplest explanation is that the RM/COBOL runtime is waiting for the operating system call to open the file to return. There is no timeout on the call (since this is a very, very rare failure mode), which is 'in process'. So, the RM/COBOL runtime has not regained control in order to report any IO error.

Assuming that your open is on an indexed file, please be aware that RM/COBOL is asserting region locks on the file (in anticipation of file sharing), including regions that do not actually exist in the 'address space' of the file, all during the series of file operations executed for a COBOL OPEN. In my first post I asked if you could execute an OPEN EXCLUSIVE INPUT because there would be less region locking, since the RM/COBOL runtime would assert an exclusive lock on the file (as opposed to a region of the file) at the file open time.

I presume that RM/COBOL is having no difficulties opening files on the 'native' UNIX file system. The nature of NFS is that the remote file system is mounted as a portion of the UNIX file system; the application is unaware that it is operating on an NFS file. The combination of these two facts would lead me to suspect that the Netware NFS implementation is not behaving entirely as it should. NFS region locking has, in its history, been a source of bugs and gross inefficiencies. I therefore suspect the Netware implementation of NFS region locking.

Since I am asserting that Netware is the problem, is there some way that you can get a trace of the requests for that file on the server? This would be a logical first step in trying to determine a cause for this problem. Tom Morrison

 

[hansie]

Tom,

I've tried OPEN EXLUSIVE as well, same problem.
The file I try to open is line sequential.
We are using NFS to im- en export text-files from several systems, and is certainly not used on critical data.
NFS worked fine on Netware 3, so we have to do some further 'homework' on the Netware 5 level...

Opening files in native Unix doesn't give any problems, on the contrary, system behaves ok, performance is excellent. 120 - 130 sessions are connected in a wan-environemnt, a lot of hits are coming from the internet, B2B and B2C ! (CGI/RPC), Unix never reports idletime < 95%. In the comming year we move to 200-300 sessions, I feel confidend with 'our' Cobol !!

If I solved the NFS-problem I will inform you in this thread.

Thanks,
Hans

 

[k5tm]

What version of RM/COBOL are you using? There may be some configuration options that might reduce the capabilities we expect in the file system. (But, I think still that this must be an issue on the NFS. A Netware trace, on the client side or the server side would help.) Tom Morrison

 

[hansie]

RM/COBOL-85 Runtime - Version 6.09.04 for AT&T Unix System V R 4.

(Kate wants me to upgrade to 7.1, I think is better to wait for 7.5)

Hans

 

[k5tm]

Hans,

Okay, that was before large (huge) file support, so I don't have any additional suggestions.

(7.5 for Windows is shipping. Several UNIX ports are in various stages of QA.) Tom Morrison

 

[k5tm]

Hans,

Any luck? Tom Morrison

 

[hansie]

Not yet, we are busy putting the system online, we are still using the NFS-shae on Netware 3 !

I will keep you informed about our progress.

Thanks,
Hans

 

[razalas]

This is undoubtedly a dumb question, but you do have a Declarative Section defined in the program don't you? &quot;Code what you mean,
and mean what you code&quot;

Razalas

 

[hansie]

Hi Razalas,

I tried both, with and without.

Thanks,
Hans