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This research was done for the WebApp Server, however it applies to anyone who wants to use a PC as a dumb terminal to run a DOS / Windows version of DataFlex against UNIX DF data.
There are many choices for s/w connectivity that will mount a UNIX drive as a NT drive. Some examples are: NFS, SAMBA, VisionFS (SCO) and FacetWin.
First, make an account with the same user name / password on NT and UNIX.
For reporting purposes where no saves occur, all that is necessary is to be able to access and read the UNIX drive.
For data entry purposes, the NT and UNIX lock managers must be in sync to preserve data integrity if data entry is performed from UNIX LAN and PC shares at the same time. That means a file locked by the UNIX runtime must be considered locked by the DOS/Windows runtime, and vice versa. Just because it works when the lock request from UNIX is granted first does not mean it will work if the lock request is granted to NT first. TEST granting the lock to the Unix side first AND granting the lock to NT side first! To test simply make a small program that opens a file(s) and asks for a lock, then and waits for a keypress to unlock, such as:
open it_locks // assume a file exists called it_locks
showln 'about to ask for a lock'
reread
showln 'lock has been granted'
inkey windowindex
unlock
Then run it form terminal / Telnet session along with a NT DOS box (dfruncon), or with the VDF runtime. It will be evident when a lock is granted and when a lock is waiting to be granted by the showln's.
I found that no assumptions can be made for the lock managers integrity. For example, SAMBA with NT / AIX was fine but SAMBA on NT / SCO UnixWare was not.
here is the samba configuration file settings that I used:
locking = Yes
strict locking = Yes
oplocks = False
fake oplocks = False
sync always = Yes
ole locking compatibility = False
More about the configuration file that must be made manually is in the SAMBA documentation.
The message is not which connectivity s/w to use but test what you are using!
For SCO, the best I found was FacetWin by FacetCorp (www.facetcorp.com) as the locks are respected on both sides, and it is really fast. As with most any of these connectivity software, you must enable "Plain text passwords" on NT as UNIX can't handle the default encryption performed by NT on user names and passwords. In NT registry add:
[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\rdr\parameters]
"EnablePlainTextPassword"=dword:00000001
Once the UNIX drive is mounted, and we have considered locking mechanism integrity, we will need to configure the VDF WebApp server to use a proper account.
Once the DF WebApp Server Administrator has been started choose: Start > programs > control panel > services : double click "VDF Internet Server".
In "Log on as" group, hit the prompt button and select the account that exists on both NT and UNIX.
For SCO / FacetWin, native DF and VDF the default FacetWin settings are fine. To run the WebApp server, you must have the NT box authenticate the user. Easiest way to do this is to install the FacetWin administrator tools on NT (setup.exe in FacetWin directory on UNIX box after product is installed) launch the administrator and log in to UNIX as root. See the security tab. Change verification from UNIX to NT_Server and enter the NT server name without slashes or IP address or anything - Just the server name. After you make the change, reboot NT for settings to take effect. For some reason, UNIX asks the VDF Internet Server for its name and password, rather then getting its account and pasword from the process ID. This results in a totally generic non-descriptive error message once you try to talk to the db as the connection times out waiting for the process to log on - but you would not know it by looking at the web page as no login dialog appears.
Jeff Haym
Data Access Corporation
UPDATE:
Data Access Worldwide will consider the use of a Linux server to host DataFlex database files that will be accessed concurrently by applications running on Windows and Linux UNSUPPORTED and NOT RECOMMENDED.
Tests were performed to confirm that the combination mentioned above produces unreliable results. The Linux version used in the tests was RedHat Enterprise Linux version 3 (kernel 2.4.21) and the version of Samba was 3.0.
Web Links Related to this Article
Facet Corporation
URL=http://www.facetcorp.com/
Linux & SAMBA as a host for DataFlex databases
URL=http://www.dataaccess.com/ContentFiles/PDF/Linux_Samba.pdf
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