The perception of Unix at that time is very interesting — this was way before X existed (X would also not have been suitable by this definition when it did beco

The perception of Unix at that time is very interesting — this was way before X existed (X would also not have been suitable by this definition when it did become available, of course). The NeXT UFS variant in 1997 was also probably still unreliable by this definition. > However UNIX is a relatively large operating system with several features such as a multiuser timesharing capability, user accounting, and protection which would be wasted in a personal computer such as the Lisa. Since the Lisa would be used by people who were not computer experts, the system must be very robust. However, the UNIX file system is fragile and unreliable [10), [14]. If the power is interrupted or a system crash occurs the UNIX file system can easily be damaged. Unless a systems programmer is present to repair the damage, a user can easily lose all his data. In addition, UNIX does not provide the general inter-task communication facility that the Lisa requires. UNIX memory management does not offer sophisticated sharing of code and data between tasks. Finally, UNIX and alI other operating systems do not provide the support for graphics, multiple windows, the mouse, integration, etc., which are essential to the Lisa. Such capabilities cannot be built on top of an operating system but must be built in to work correctly and efficiently. An attempt to modify UNIX to overcome all of these deficiencies would have taken longer than designing a new operating system with all of the needed capabilities.