[comp.os.minix] SUID bit patent and Minix - question

ira@slovax.UUCP (02/16/87)

(I just received my copy of the Minix book and have only started reading
it, so if the answer may be found there, I appologize up front.)

The Set User ID bit in the directory is protected by United States
patent number 4,135,240.  Minix appears to have the same capability.
Did Tanenbaum or Prentice-Hall license the patent from AT&T?  If not, under
what conditions can the Set User ID bit concept be employed without an
AT&T license?

While on the subject, does anyone know if the Set Group ID bit (which is
not explicitly mentioned in the patent) is also covered by said patent?