michels@tramp.colorado.edu (MICHELS DAVID) (02/15/91)
Can anyone tell me the story of Prodigy? I know it is an IBM/Sears joint project. What I would like to know is what was contributed by who. I would imagine, IBM provided the computers, the know how, the telecom infrastructure, and all other technical aspects, is this true? What did Sears provide, just cash? Someone told me all the telecom goes thru Tymenet, is this true? I would have expected IBM to piggy back prodigy data on its National Physical Network (NPN). Why would they treat Prodigy so independently? I would appreciate any insights, Dave
tnixon@uunet.uu.net (Toby Nixon) (02/17/91)
In article <telecom11.116.7@eecs.nwu.edu>, michels@tramp.colorado. edu (MICHELS DAVID) writes: > Can anyone tell me the story of Prodigy? I don't know everything, but I do know a bit more than you it seems, so I'll try to answer your questions. > I know it is an IBM/Sears joint project. It initially included CBS as well. CBS later wanted out and their share was bought out by IBM and Sears. > What I would like to know is what was contributed by who. > I would imagine, IBM provided the computers, the know how, the telecom > infrastructure, and all other technical aspects, is this true? > What did Sears provide, just cash? Sears provided their vast mass-marketing expertise. Prodigy is almost totally advertiser-funded; you see a little ad displayed on the bottom of every screen, unless the full screen you're looking at happens to have been provided by an advertiser! Sears did the basic market research, focus groups, etc., that resulted in the design of the service, recruited many of the advertisers, etc. -- i.e., handled the commercial, as opposed to technical, aspects of the service. Sears was also the first commercial outlet for the Prodigy Startup Kits (which included a Hayes Personal Modem 1200, later 2400, by the way); you can now get them just about anywhere, of course. IBM, of course, saw Prodigy as a great way to get more PCs into more homes. > Someone told me all the telecom goes thru Tymenet, is this true? I > would have expected IBM to piggy back prodigy data on its National > Physical Network (NPN). Why would they treat Prodigy so independently? Prodigy over Tymnet is a very recent innovation. Prodigy started out with just a couple of cities, and has been spreading slowly as they installed their own nodes. Traffic was indeed carried on IBM's network. But the hardware on which Prodigy runs is much different from a typical packet network, where the network is just a pipeline and all of the data is in the hosts. Prodigy network nodes are very intelligent (IBM Series/1 computers) that have very large databases of screen images. The software you run on your PC does the same thing! Whenever you take an action that would cause a different screen to be displayed, it first looks at your local disk (screen cache), and gets the image from there if possible. If it's not there, it checks the disk at the node. If it's not there, only then does it go all the way across the network to fetch the image from the host computers in White Plains. This staging of images improves the performance considerably, especially on images that don't change very often (menus, etc.) and that are used by others as well. By the way, I might comment on why it is that Prodigy was so concerned about high levels of email traffic. Email on Prodigy CANNOT be staged on the nodes -- it HAS to go all the way to White Plains for every screen. Heavy email traffic saturates the network, which can bring it to its knees very quickly. Email was intended to be an occassional convenience feature, not a primary use of the service. I don't know how Tymnet fits into this. Certainly Tymnet's node processors don't have the ability to cache screens, but maybe still rather than going all the way to White Plains there are distributed caches around the country. I just don't know. But Tymnet access was added by Prodigy in order to expand the user base (probably at the demand of advertisers) much faster than could have been done by the gradual installation of more S/1 Prodigy computers in new cities. Toby Nixon, Principal Engineer | Voice +1-404-449-8791 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net
news@casbah.acns.nwu.edu (Mr. News) (02/18/91)
hayes!tnixon@uunet.uu.net (Toby Nixon) writes: >By the way, I might comment on why it is that Prodigy was so concerned >about high levels of email traffic. Email on Prodigy CANNOT be staged >on the nodes -- it HAS to go all the way to White Plains for every >screen. Heavy email traffic saturates the network, which can bring it >to its knees very quickly. Email was intended to be an occassional >convenience feature, not a primary use of the service. Well, I won't bother to comment on the utter stupidity of the conclusion that email was going to be a minor feature of a nationwide consumer computer network, even absent of the fact that email was encouraged as a way to deal with the "editing" of messages posted to the Prodigy Forums. Obviously, Sear's massive market research didn't include logging on to any of the other online services ... ;) However, I do take issue with the statement that "Email on Prodigy CANNOT be staged on the nodes." Thats simply not true. It could very easily be staged. Since Prodigy knows which local host a user last logged into, and since it is probably a 95% probability (or more) that he will log into this same host on his next session, that host can be declared to contain his "mailbox", and mail can be catched there in anticipation of his next access. Insofar as "instant" delivery of mail is concerned, the only time Prodigy has to be concerned with priority delivery of mail from the central host to the local cache is when the user is actually on the system and in the email application; otherwise, mail that is sent to the user can be sent to the cache during times of low system utilization. Of course, the five percent of the time when the user changes local nodes doubles the overhead for pending mail, as it has to be sent from the old local node through the host to the new one (I assume that Prodigy, being cheap, doesn't want to spring for the extra disk space to duplicate email on the host and the local nodes). However, since this only happens one time out of twenty, and the other nineteen times the cost at the time of reading is near zero, you are looking at about a 80% decrease in the "cost" of sending email, at least. Finally, PRODIGY can easily deal with the huge mailing lists by not transmitting an identical copy to each recipient, but rather just one copy to each node that has recipients for it. Why they did it the way they did is a story I for one would like to hear. Robert J. Woodhead, Biar Games / AnimEigo, Incs. trebor@foretune.co.jp