Visual Basic Application hangs across a Workgroup LAN

[krshep]

We have four XP Pro PC’s in a Workgroup LAN. The front two PC’s are connected by a Router/Ethernet Switch, which is connected to the rear two PC’s by another Ethernet Switch. The LAN has a D-link DSL cable modem connected to the D-link Router/Switch at the front and a network printer (Cannon IR300) is connected to the rear Ethernet switch.

The problem is that an application operating on each of the three PC’s is so slow that any more than one instruction hangs the application and in some cases can hang the designated server, which has the data files. The front two PCs are used for POS and the rear two for stock check and input and Admin.

Each PC has a unique name.
Each PC has the workgroup ‘MSHOME’.
Three PC’s have a mapped drive ‘S’ to the designated server.
All PC’s have the guest account enabled.
All PC’s have a shared_media folder shared to the network with full permission.
All PC’s have their IP’s automatically allocated and each has access to the Internet.
All PC’s can see each other and each can use the network printer.
All PC’s can see the each other as well as all shared folders, and all Mapped drives.
All PC’s have the XP firewall turned off.
All PC’s have Client for MS Networks
File and Print Sharing for MS Networks, and
Internet Protocol TCP/IP.
All PC’s have NetBIOS over TCP/IP enabled.
All PC’s have Node Type of ‘Broadcast’.
All PC’s have the Browser running.
All PC’s have simple file and print sharing enabled.
All PC’s have HDD format of FAT 32 not NTFS.
All PC’s have the same Subnet Mask of 255.255.255.0
Three PC’s (AMD) use Rhine FAST Ethernet II on board NIC’s.
One PC (Celleron) also uses on board NIC.

The Network diagnostic program detects no errors.

All PC’s are operating XP Pro, three have AMD Athlon 3200+ 2.0GHZ processors and 1 older PC is a Pentium 3 Celleron. The older Celleron is one of three PC’s that used to run the ‘Point of Sale’ application written in Visual Basic without much problem. Since updating to the newer AMD machines the network is almost unworkable.

The PC’s can all see each other and all shared drives as well as the mapped drives but anything at the program level hangs and brings a (not responding) message until completed. If you wait long enough, typically a few minuted it will clear but in a shop you don’t always have a few minutes to wait. The girls just avoid using anything too complex on the second PC, and just use it as a cash register.

The above configuration is the result of many hours scouring the Internet and checking the network settings, but to no avail. Anyone with any good ideas or anything else I should check would be much appreciated.

[cszeto]

Since this is in support of a business network, you might try http://www.enterpriseitplanet.com. They also have a forum too and it is geared at business networks.

This is pretty much beyond the scope of most SOHO networks, so there may not be too many responses to this subject across these forums. If this is occurring across a single application, then you might consider getting the application and networking folks together to address the specific networking needs of this particular application.

One possible consideration is to manually set all the network adapters (NICs) to the maximum speed of the network, typically 100 mbps. The changing application performance after the introduction of the new systems may indicate incompatible or incorrect speed/duplex detection across the network components.