Learn has been installed on many different UNIXsystems. Most of the usage is on the first two scripts, so these are more thoroughly debugged and polished. As a (random) sample of user experience, the learn program has been used at Bell Labs at Indian Hill for 10,500 lessons in a four month period. About 3600 of these are in the files script, 4100 in the editor, and 1400 in advanced files. The passing rate is about 80%, that is, about 4 lessons are passed for every one failed. There have been 86 distinct users of the files script, and 58 of the editor. On our system at Murray Hill, there have been nearly 2000 lessons over two weeks that include Christmas and New Year. Users have ranged in age from six up.
It is difficult to characterize typical sessions with the scripts; many instances exist of someone doing one or two lessons and then logging out, as do instances of someone pausing in a script for twenty minutes or more. In the earlier version of learn, the average session in the files course took 32 minutes and covered 23 lessons. The distribution is quite broad and skewed, however; the longest session was 130 minutes and there were five sessions shorter than five minutes. The average lesson took about 80 seconds. These numbers are roughly typical for non-programmers; a UNIXexpert can do the scripts at approximately 30 seconds per lesson, most of which is the system printing.
At present working through a section of the middle of the files script took about 1.4 seconds of processor time per lesson, and a system expert typing quickly took 15 seconds of real time per lesson. A novice would probably take at least a minute. Thus a UNIX system could support ten students working simultaneously with some spare capacity.