Thank you Al and Tracy.
Bruno


>>>Does the NAS support multiuser-locking in databases and Opportunistic Locking? Is it configured to do so?
>>
>>How can I verify that?
>
>Most NAS boxes are low-end computers running a variant of Linux. In order to provide SMB (Windows-compatible) networking, they typically run Samba: http://en.wikipedia.org/wiki/Samba_%28software%29
>
>Whether the NAS will support multi-user lock mechanisms for Windows clients therefore depends on how Samba is configured. Although Samba is capable of supporting multi-user access, it may not be configured to do so on your NAS by default.
>
>Many NASs are aimed at home users, who will never run multi-user applications against it so in many cases multi-user support may not be enabled. Also, performance of low-end NASs is poor, so the maker may actually disable multi-user support, which would otherwise reduce performance further.
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>Business-oriented NAS boxes *may* support multi-user access.
>
>Your best bet would be to contact the manufacturer of your NAS and ask them. Or, post a message on a support forum for the device. If the issue actually is that the NAS does not by default support multi-user, then there are a few possibilities:
>
>- if you're lucky, there may be an option in the NAS's (usually web-based) configuration tool to enable it
>- the manufacturer may have instructions on how to enable it some other way
>- you may need to hack the device and manually edit Samba configuration files
>- worst case scenario, the NAS may not support it at all (e.g. using something other than Samba to provide SMB)
>
>Even if you can get it working, you may find that performance of your application against the NAS is poor, unless the NAS is a high-end unit.