Definition of Mandatory

Jim McGrath jmcgrath at
Fri Sep 2 13:22:43 PDT 1994

        Reply to:   RE>Definition of Mandatory and Optional Features in SAM


Thanks for your work on mandatory vs optional - it helps to fill a big
hole in all of our current standards.  But I have some difficulty with
your set of standards and their relationships.  First, I still feel that
SAM is a "standard for standards", and that it has no direct
controlling influence over implementations.  That is the function
of the specific standard documents.  Indeed, this is the key property of
an architecture - it sets some boundaries on implementations, but does
not directly address itself to implementation issues.

If you wanted to roll in some implementation requirements, then I could
live with that.  But your example wording implies that EVERYTHING in
SAM automatically becomes an implementation requirement (or option).
Moreover, SAM talks of entities such as the task set that does not have
any discrete existance - parts of it exist in a host device, some in the
target device.  Requiring some functionality in such an entity has no
enforcability - you have to specify requirements in terms of what
people actually produce - hosts and targets.

At the end of the day, I am still concerned over possible confusion between
things SAM requires of standards and things it requires of implementations.
And since it is not focused on specific implementations, it is very hard
for it to make implementation requirements in a manner that is clear and
enforceable to the designer of a specific device.


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