🚀 go-pugleaf

djohnson@beowulf.ucsd.edu (Darin Johnson) writes:

>In article <t22918.665454268@ursa> t22918@ursa (Matt Ranney  ) writes:
>>Why can't Amiga's handle failed tasks like the Unix OS can?  I'd be perfectly
>>happy to have my computer tell me that a task failed, and all it's allocated
>>resources had been returned.

>Herein lies the problem.  The OS does not keep track of allocated resources.
>(sigh)  However!  the GOMF program (commercial, but old PD version on
>a Fish disk) will attempt to recover resources from failed tasks, remove
>the task, and let you continue on your way.  It doesn't do a perfect
>job, but works most of the time, with only a little loss of memory.

The reason that Unix almost never crashes is usually because of the memory
protection hardware which is required to protect processes from tampering with
memory areas they don't own. In the Amiga a program can rampantly wade through
memory trashing areas. In Unix you'll get a segmentation violation and thus
avoid crashing any of the other processes and also make it easy to clean up
the dead process. A stock Motorola 68000 is not capable of attaching an MMU
(Memory Management Unit), although the 68020 and 68030 chips are. I have heard
of a program called Enforcer which uses the MMU on a 68020 or 68030 to provide
a more protected environment. It also attempts to provide cleanup. However,
since the original OS wasn't designed to use it, it isn't quite as effective
as the Unix method. I'm also not sure whether it runs under 1.3, 2.0 or both.

| Shawn L. Baird                        | Or via US Snail:                  |
| bairds@eecs.ee.pdx.edu                | 17650 SE Cason Rd.                |
| ...uunet!tektronix!psueea!eecs!bairds | Gladstone, OR  97027              |