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Data Exchange Protocol Extensions

After the first implementation of the data exchange protocol, two bottlenecks were immediately found. The first is that with large volumes of transmitted data, the transmission time has greatly increased. Secondly, if during the transfer you press a key, the key code gets into the general stream and spoils the data, and if the key was of the control type F1, then the ESC character got into the stream, and the transfer stopped, and garbage was thrown onto the screen.

The second drawback was won immediately – upon receiving the conditional ESC-sequence, they began to block not only the output to the screen, but also the transfer of data that were not desirable at that time. In this mode, keystrokes and insertions from the Clipboard were ignored. These events were processed, but the parcels were not carried out putty download.

It was more difficult to fight the first drawback. But the lifeline turned out to be the use of the ZLIB library. True, I had to make the transfer block. But, since 95% of files are text only, they are compressed very well. After the compression of the data stream was implemented, the transfer rate of large files increased 50-100 times.

findings

Thanks to the use of this technology, now from the main CHUI system we can satisfy almost all the requests of our customers who wanted everything to work quickly and modernly. And they got it – the speed and efficiency of CHUI plus the beauty and visibility of reporting in office applications.

However, when working with CHUI (in the future this abbreviation will imply OpenEdge sessions under Linux / Unix) very often raises the question and the interaction between the program on the remote server and the workstation. And for many, the inability to print something on a printer, open a file in one of the office applications (MS Word, OpenOffice Writer, …), or put the file on a local disk without using additional software is the very barrier that makes decisions about abandoning the OpenEdge platform, even with economic and strategic advantages.