PHP/MySQL application - how to schedule server processes?

Hi there, I wonder if anyone can offer me some advice... I have developed a portal using PHP, which allows users to uploads files into their own personal storage locations. These files are stored in a MySQL database. The system also allows the users to select these files and submit them for analysis. By "analysis", I mean that these files will be used as the input to separate executables (written in C) running on the server. This aspect of the system be accomplished in 2 ways: CASE 1: Where the analysis program has a run time of less than 1 second (nb: the amount of users estimated at any one time is no greater than 10). Here, the file can be extracted, a command line argument generated, and then passed to the server via the PHP passthru() function. The result will then be returned to the user. Easy peasy. CASE 2: Where the analysis program may have a run time in excess of 2 hours. The passthru() function is obviously not an option as we do not expect the user to sit in front of the computer for a few hours, or even minutes waiting for a result. I am not sure as to the correct terminology, but I believe I am looking for something like an 'application server' / 'process management scheduler'. Maybe something that is commercially/freely available, or an idea of how to go about writing my own. Here is a rough idea of what I am trying to accomplish: The user accesses the web application and, and selects a file for analysis. The system (implemented in PHP) updates the databases to say that 'ANALYSIS A' of 'FILE B' has been requested. A separate entity running on the server watches the database for analysis requests, and either (a) runs them one after another & updates the database appropriately (b) or schedules according to some priority. When each analysis is complete, the user will have access to the a results folder in the system containing a list of their submitted analysis (either pending or complete). Can anyone offer any advice/suggestions on how this can be accomplished? Thank you very much for your time. - Best regards, Lee Reilly -- Lee P. Reilly, ms:G758 Szilard Resource, tel:505-665-7025 Bioscience Division, SM-30 Bikini Atoll Rd, Los Alamos National Laboratory, mailto:lreilly@lanl.gov Los Alamos, NM 87545. http://home.lanl.gov/lreilly "Quidquid latine dictum sit, altum viditur" <filter>PHP SQL</filter>