vi core dumping on Sun 2 (fixed, but would like explanations)

[Tim Smith]

The problem lies, I believe, with the sticky bit.  You mention that vi has
the sticky bit on.  Assuming that 4.2bsd treats this bit the same was that
UNIX does, then this means that there will be a copy of the text of vi on
the swapping device ( or maybe pageing device ).  Assume that this copy is
bad.  I think all your symptoms are explained then:

> 1) Binary hadn't been modified at all since pulled off the Sun release tape.
> 2) Rcp-ed vi from another Sun over ethernet and did a ``cmp'' on the two
>    binarys and noted they were EXACTLY the same.

Fine.  cmp opens /bin/vi, and gets the data from the filesystem, which has
not been trashed.

> 3) Tried running the vi binary from the other Sun, noted it works FINE.
> 4) Tried copying the vi binary to another file, works FINE.

To be expected, since cp gets the data from the filesystem.

> 5) Get clever.  Notice vi has 6 links, make 5 links to the other Suns vi and
>    run it.  Works FINE.
> 6) Get cleverer still.  Notice vi has sticky bit turned on, so turn on the
>    sticky bit of the other vi, try that.  Works FINE.

All this is being done to the new vi.  The old one is still sitting wounded
on your swapping or pageing area(s). 

> 7) Rebooted system, problem goes away.      <************* NOTE *************

Rebooting makes the system forget the bad copy on the swapping area.
-- 
					Tim Smith
				ihnp4!{wlbr!callan,cithep}!tim