Date: Thu, 29 Oct 1992 14:09:05 -0500 From: Jim Davis <davis@dri.cornell.edu> Message-Id: <199210291909.AA17963@willow.tc.cornell.edu> To: www-talk@nxoc01.cern.ch, wais-talk@quake.think.com, Subject: In-band v.s outband labeling. (was: Misconceptions about MIME [long]) I wish that people would take a less inflammatory tone in the mail, and try to assume that even if some parties may be wrong, they are at least possessing good will and a desire to find solutions that work for all users. Larry says he has a problem. As I understand it, his problem is that moving data is expensive, so he wants to have more information available at the client before retrieving the data. Why would anyone object to this? Does it help to consider that someday, maybe soon, much network data will be sold for a fee. Would you object to customers wanting information about data before paying the price? If we agree this is a real problem, then we face the problem of finding a solution that is practical, efficient, compatible, and so on. Now, as N Freed points out, no method exists to automatically compute in the general case the resource requirements of e.g. PostScript, that has little bearing. For one thing, there are many data types which are not turing complete programs (e.g. GIF files). For another, the person who produced the PostScript in the first place probably knows the measurements. After all, if I created a .PS file and put it on the net, I probably displayed it at least once, so I know well enough that it does halt. (unless I am malicious.) And finally, even if the creator does not tell you, you can still compute it, once, and then store the results in the file archive, or Wed, or whatever. The fact that a full, general and automatic solution is impossible does it lessen the value of partial solutions. So the proposed solution is to have more explicit labeling. What's wrong with that? If you dont use it, it costs nothing. If you do use it, it makes life easier for people. You can argue that many people are too lazy to provide this information, and I agree But not everyone is lazy. there will also be people motivated to expend the trouble to label the data, yes, even to go to the extent of computing how much main memory you will need to uncompress and so on. Why will they be motivated? Because those who do will have larger audiences, and that is already a motivation. And when money starts to enter the picture, the motivation for market share will be stronger. There will be a consumer's union and an underwriters laboratory for information space. The question is where to put the information, the "meta data" if you will. Best wishes