Difficult to use

The main difficulty for the average user resulted from a multiplicity of naming conventions. One naming convention was a leftover from an early experimental system, since the software originally written for it had not been changed. Other naming conventions resulted from the fact that in the final system the user had to be cognizant of at least three directories that might contain the file he wanted, his temporary directory, his permanent directory, and a system directory. We supplied one naming facility which gave full access to his permanent directory, and another which did not, in order to protect him from undebugged subsystems (a protection not generally provided in other operating systems). Finally, a user who desired to write his own subsystems was in severe difficulty, since we had no complete manuals covering all of the conventions he had to know. Consequently the only successful subsystem writers were our own staff and a few determined and inquisitive users.