mss+@andrew.cmu.edu (Mark Sherman) (07/06/90)
I have a class of students using MacScheme from an Appleshare file server (yes, we have the necessary site license). After some number of students start using the program (a variable number, say from 10-14), every student in the same zone who tries to launch the program immediately gets an "application is busy" dialog box. Examining the file with ResEdit reveals that both the InUse and File Busy bits are set at that time. When no students are using the program, neither bit is set. Among other observations: if we make additional copies of the program on the same server, sometimes some more students can run the additional copies, but no where near the 10-14 who could run the original. If we make local copies of the program in external disk drives (or hard drives), then students can always run the local copy. If students try to use a copy placed on another servre in another zone, only one or two more students can get it going. There does not seem to be a problem with someone outside of the zone of the server/students firing up the application (that is, my office is in another zone, and while the students cannot launch the application from the server, I have no problem launching the same file from a machine in my office). Inter*poll reveals nothing unusual (for the things it can monitor). All of the students are registered on the server with the same ID (a class id). Everyone in the course is using identical disks with system 6.0.4 on them. The students do not have a problem connecting to the file server. We do not see this problem with other programs the students are using on the server. The MacScheme program appears to be written in Consulair C. One explanation I have heard is that when a launch is aborted, it leaves the file in a busy state, preventing further launches of that file until an appropriate time out on the server. I have not been able to verify or induce this circumstance manually. I've gone over the problem with site maintainers, Mac programmers and network wizards. (I myself have a passing understanding of how the Mac and Appletalk works.) We do not have an explanation that satisifies all of our observations, or that implies a solution. Any ideas? -Mark