[EROS-Arch] Package handling...

[Bill Frantz]

At 12:19 PM -0800 3/28/01, Joerg Bornschein wrote:
>
>How did uninstallation work in KeyKOS?

For system-wide installations, we followed Alan Karp's approach and kept
the old versions.  For test installations, we just blew away the space bank
and let the null keys fall where they may.

In one case, we actually replaced the code segment of a running system-wide
class of objects.  Since the objects were not designed from the start for
upgrade, the binary code patch was very delicate.  With forethought, it is
possible to build objects which check if an upgrade is available and
automatically upgrade themselves.  It requires a lot of thought about the
necessary data conversions, and how you maintain compatibility.  That level
of thought is probably "good for you", but no one that I know is in the
habit of thinking that way.

Cheers - Bill


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