SCO Unix Serial Communications and UUCP

This article is from a FAQ concerning SCO operating systems. While some of the information may be applicable to any OS, or any Unix or Linux OS, it may be specific to SCO Xenix, Open There is lots of Linux, Mac OS X and general Unix info elsewhere on this site: Search this site is the best way to find anything.

I increased my SCO Unix UUCP window size but nothing changed

This is an ancient post with no relevance to modern systems.

When UUCP is negotiating a connection, each side will tell the other what window size to use when sending. Therefore, if your window size is 7 and the remote uses 3, you will be sending files using a window size of 3, but the other side may send with a window size of up to 7. Note that the UUCP on the other side may not support the window size you specify, and may send with a smaller window than you requested. While this should not cause problems, it may provide lower performance than you'd like.

If your connection does not have data compression, error correction, or long transmission delays, and the two sites involved have sufficient CPU power to respond quickly to incoming packets, a window size of 2 or 3 should be sufficient to achieve streaming data flow. In this case, a larger window size will not provide any benefit.

If you have a Telebit modem, see the Telebit notes below.

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