+.NH
+Experience with Students.
+.PP
+.I
+Learn
+.R
+has been installed on
+many different
+.UX
+systems.
+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
+.I 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.
+.PP
+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
+.I 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
+.UX
+expert can do the scripts at approximately 30 seconds
+per lesson, most of which is the system printing.
+.PP
+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.
projects / unix-history / commitdiff