RE: package SYSTEM

[Bakin@MIT-MULTICS.ARPA ("David S. Bakin")]

1)  Just for information, DEC Ada puts in system functions dealing
with manipulations on type ADDRESS, PEEK and POKE type routines,
definitions of the 4 VAX floating point types, definitions related
to VMS stuff like ASTs (asynchronous system traps) and non-Ada
exceptions, and operations on unsigned bytes and arrays of bits.

2)  Just for information Alsys Ada puts in SYSTEM functions
dealing with manipulations on type ADDRESS, PEEK and POKE type routines,
and (depending on the particular target) convenient declarations on
other types such as unsigned bytes.

3)  What do other compilers have in package SYSTEM?

4)  I don't understand why the "dynamic priority" problem is a problem
of package SYSTEM.  Although SYSTEM seems a place for it at the implementor's
choice, if forbidden to put such a thing in SYSTEM why can't he put it
somewhere else (i.e., a different library package, or a different
pragma)?

5)  Lets say you'd like your Ada compiler to offer 'freebies' (that is
features not mandated by the language) such as convenient operations on
packed arrays of bits (e.g., "and", "or" operators).  Then do you prefer
to have them in package SYSTEM or in some other library package?  I'm
asking because I'd really like to know the opinion of user's.  To me
it doesn't seem to make any difference because its not portable to use
such features anyway, the only thing I could say is that having them
in SYSTEM is a convenient "flag" to the reader when he sees the context
clause at the top of the module -- the same argument which was first
applied to the use of UNCHECKED_CONVERSION, UNCHECKED_DEALLOCATION.

6)  Does anyone think an implementor is going to put hooks in to the
run-time system to allow non-Ada tasking?  Does anyone think an implementor
is going to be asked by a user to do such a thing?  Does any user PLAN to
ask such a thing?  I think it much more likely that an implementor will be
asked to adapt his run-time system to implement Ada tasking semantics on
top of an existing OS or monitor program than be asked to implement non-Ada
tasking semantics.

-- Dave

(Normal disclaimer about me and my big mouth vs. Alsys and its corporate
policy.)