rjf@eagle.ukc.ac.uk (R.J.Faichney) (08/22/88)
This was originally emailed to Suu Quan, but I couldn't get a route that worked. As there may be others interested -- this contains a little more info than previous articles on the same subject -- I decided to go ahead and post it. Hope nobody objects! (In case they do: I promise this will be the last on this subject for some time.) Hello Suu, Sorry about the delay in getting back to you -- I have been rather busy. Also, your address is not clear -- I hope this reaches you. dp is a system designed to make IPC easy for application programmers. It is primarily intended to connect the underlying functionality modules, as opposed to the user-interfaces, of interactive applications where these are strictly separated, but may as easily be used where there is no such separation. Strictly speaking, 'connect' is wrong, as both continuous connections and discrete connections are provided. Data is basically unstructured, but may be either a null-terminated string or have the number of bytes specified, and may have a 'magic number' accompanying it to guide interpretation. Control codes, in the form of an integer, may also be sent. Information on other currently executing dp applications may be requested. Addressing is network transparent -- where an address is required (mainly for all discrete messaging) any combination of application name, user and host may be specified, with unspecified host meaning 'any host on the local network'. Hosts beyond the local net may be reached (as long as they have dp installed!) by giving the Internet address (inet(3N)) instead of host name. At the moment we are considering releasing beta test versions of dp and vconf. No decision has yet been taken, but we'd require only the price of a tape and an assurance of no disclosure nor commercial usage. I guess it would have to be official, from your organisation rather than yourself, but I'll check up on that. Let me know if you are interested. I should say that vconf was only intended as a test/demo for dp, is based on no conferencing research, and would not be fun to maintain in it's present state. On the other hand it works under Sunview, X10.4 and X11.2, on Sun3s, VAXstations, and sometime RSN, Sun2s. If you send your physical address I'll send a copy of the paper on dp when it is ready. Meantime, I'd be very interested to hear what you have been doing. Robin ..uunet!mcvax!ukc!rjf