Help writing first daemon

[Patrick <patrick@spellingbeewinnars.org>]

Hi Everyone

I am setting out to write my first daemon. There seems to be a lot of options for inter-process communication on posix systems. I am planning on designing a scientific instrument control server that will control ports, like the serial port, based on signals it is sent. It will also collect data from instruments and store the data(I was thinking in a postgresql database).

I just need signals passed on one machine so yaml4 seems like overkill. I was thinking that I could write many little commands, with each command specific to an instrument it is designed to control and the daemon as more general infrastructure(basically middleware), so it wouldn't really be a parent/child relationship. I'm guessing plain old pipes are out.

Does FIFO/names pipes sound reasonable for this sort of thing? I am concerned that with many commands acting on the daemon there will be too much overhead with these commands creating file handlers.

I am also going to control instruments over Ethernet anyways so would investing time in socket programming solve two problems by making it a socket based server? Once the socket is set up by the daemon, the smaller "satellite" commands would not need as much overhead to connect to a port as they would to create a file handler, would they?

Lastly, this will be done in Ada where ever possible, is there an Ada oriented way to do this sort of thing?

Thanks for reading-Patrick