|
| KerrAvon wrote:
| 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.
| Animats wrote:
| If only the Motorola 68000 line hadn't taken so long to come up
| with a usable MMU. Computing history could have been very
| different.
|
| 1979, M68000, CPU, instruction backout broken, so if you wanted
| to handle page faults, you needed to avoid all multi-step
| instructions.
|
| 1993, M68010 CPU, fixed backout bug.
|
| 1987, N68030 CPU with MMU, page faults work.
|
| Early machines required boards full of extra hardware to work
| around this problem. Which is why the Macintosh, unlike the Lisa,
| had a plain 68000 MMU and a DOS-like OS hidden by a very nice
| GUI.
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