Data sharing by files

Two or more applications (in the network or on one computer) can also share data by means of file sharing. Both applications must know the exact file format. In many cases this is the only practical way of the data transfer.
The disadvantage of this data transfer is the impossibility to trigger event in the other application based on change of the data file. It means that if the first application writes into the file, then the other application doesn't know about it. The change is found out only when the other application reads the file itself or when the first application informs it by another way.
The other even greater disadvantage is the unreliability of disk operations in the computer networks. File sharing in the network is slow and on the outage of the remote computer the unsuccessful access can take too long. Thus on the network disk operations it is good at first to find out the presence of the remote computer in the network, for example by the Pm.NetTestPC method.

Read or write data into the file in the PROMOTIC system can be made by methods of the object in the Pm variable: