Network Simulation 
Author Message
 Network Simulation

Hello All,

I am preparing to modify my Summer '87 code to accomodate a LAN. The LAN
is
not yet "hooked up" and probably will not be ready for about 2 months. In
the meantime I want to familiarize myself with "locking" and "unlocking"
of files. Can I simulate a network enviroment by running an EXE program
from Windows 3.1 and while that program is running, switch back to File
Manager and run the EXE again?

It doesn't seem to be working... During the first session, I run the
program to a wait state where I know a specific file is supposed to be
"locked" (ie: USEd EXCLUSIVE). Then I switch to File Manager and run the
EXE a second time. During this second session I can still access that same
file. Does this mean that the lock was unsuccesful during the first
session? Or is using Windows not a valid way to simulate a network?

Thank You,
Fred
San Diego



Tue, 12 Oct 1999 03:00:00 GMT  
 Network Simulation



Quote:
> Hello All,

> I am preparing to modify my Summer '87 code to accomodate a LAN. The LAN
> is
> not yet "hooked up" and probably will not be ready for about 2 months. In
> the meantime I want to familiarize myself with "locking" and "unlocking"
> of files. Can I simulate a network enviroment by running an EXE program
> from Windows 3.1 and while that program is running, switch back to File
> Manager and run the EXE again?

> It doesn't seem to be working... During the first session, I run the
> program to a wait state where I know a specific file is supposed to be
> "locked" (ie: USEd EXCLUSIVE). Then I switch to File Manager and run the
> EXE a second time. During this second session I can still access that
same
> file. Does this mean that the lock was unsuccesful during the first
> session? Or is using Windows not a valid way to simulate a network?

> Thank You,
> Fred
> San Diego

I also simulate a network in the same way you do except that ....
I use Windows '95.

I have no experience with Windows 3.1 but in Windows '95 it
just works fine. Files or records who are locked in one DOS-box
cannot be opened in a second DOS-box in a Clipper-application.

So, maybe the solution for you is to upgrade to Windows '95.

Good luck

--
Michel Driessen
M&A Consult bvba
Genk (Belgium)




Wed, 13 Oct 1999 03:00:00 GMT  
 Network Simulation


Quote:
>Hello All,

>I am preparing to modify my Summer '87 code to accomodate a LAN. The LAN
>is
>not yet "hooked up" and probably will not be ready for about 2 months. In
>the meantime I want to familiarize myself with "locking" and "unlocking"
>of files. Can I simulate a network enviroment by running an EXE program
>from Windows 3.1 and while that program is running, switch back to File
>Manager and run the EXE again?

Try running SHARE.EXE before you run Windows. W'95 runs VSHARE by
default.
---


             WWW  http://www.iag.net/~philb/
        FTP Site  ftp://ftp.iag.net/pub/clipper



Thu, 14 Oct 1999 03:00:00 GMT  
 Network Simulation

<snip>

Quote:
> "locked" (ie: USEd EXCLUSIVE). Then I switch to File Manager and run the
> EXE a second time. During this second session I can still access that same
> file. Does this mean that the lock was unsuccesful during the first
> session? Or is using Windows not a valid way to simulate a network?

Unless you load the SHARE utility under DOS, there is no support for
application level file/record locks. Load it prior to running Win 3.11.

Win 3.11 has it's own file sharing built in (VSHARE.386) but only for
Windows applications. I also vaguely recall something about possible
problems if both SHARE.EXE and VSHARE.386 so you may want to investigate
that further. I have done what you described in the (distant) past, and
I don't recall any problems.

Gary



Thu, 14 Oct 1999 03:00:00 GMT  
 Network Simulation

Quote:

> Hello All,

> I am preparing to modify my Summer '87 code to accomodate a LAN. The LAN
> is
> not yet "hooked up" and probably will not be ready for about 2 months. In
> the meantime I want to familiarize myself with "locking" and "unlocking"
> of files. Can I simulate a network enviroment by running an EXE program
> from Windows 3.1 and while that program is running, switch back to File
> Manager and run the EXE again?

> It doesn't seem to be working... During the first session, I run the
> program to a wait state where I know a specific file is supposed to be
> "locked" (ie: USEd EXCLUSIVE). Then I switch to File Manager and run the
> EXE a second time. During this second session I can still access that same
> file. Does this mean that the lock was unsuccesful during the first
> session? Or is using Windows not a valid way to simulate a network?

> Thank You,
> Fred
> San Diego

Dumb question but are you testing for a network error,by using
neterr() first. I dont have Summer of 87, and dont know if this function
was available then.

Open the file exclusivley, then if you open the file again in another DOS
Box under windows and test for neterr() once an open is attempted, If
neterr() is true, then the file is locked for exclusive use. Having the
file locked for exclusive use does not stop another user being able to
read it, just cannot write to the file.

By the way, there is no need to Load Share.Exe under WFW3.11. You have
not specified whether you are using WFW3.11 or not

--
=================================================================
Lawrence Edelstein           Parcelnet Australia
Tel   :  (03) 9427-7611      Level 1, 504 Swan Street
Fax   :  (03) 9427-7060      Richmond Victoria
Mobile:  (04) 1114-8778      Australia
=================================================================



Sat, 16 Oct 1999 03:00:00 GMT  
 Network Simulation



Quote:

>Having the
>file locked for exclusive use does not stop another user being able to
>read it, just cannot write to the file.

That is true of a FLOCKed file, but a file USEd EXCCLUSIVEly can not
be read by another user.
--
Doug Lee                | "It's not easy to be crafty and winsome at
Metro Vision, Inc.      | the same time, and few accomplish it after



Sat, 16 Oct 1999 03:00:00 GMT  
 
 [ 6 post ] 

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