john gilmore wrote:
Chris Craddock writes:
|
| . . . I am glad that the wizards have made it all work out, but in
terms of functional needs,
| 64-bit addressing is overkill on a cosmic scale.
|
Let us hope so.
Computing---informatique, informatica, whatever---is a fairly new
discipline; but one red thread that runs through its brief history is
that nothing is ever big enough for long. External names at most eight
characters in length, DDNAME values at most 44 characters in length,
varying (halfword current-length prefixed) strings at most 32767 bytes
in length, fullword values not larger than 2147483647, etc., etc., have
all proved to be too small.
Moreover, address spaces first 24 and then 31 mibibytes in size have
quickly proved to be too small, not for every application but for some
crucial ones.
The moral of this anecdotage is that notionally "reasonable" maxima have
in our history always been outgrown much too soon.
Another obvious point to make is that this storage is virtual not real
storage. All of it need not be backed up, and what is backed up need
not even be connected (contiguous); and still another perhaps not quite
so obvious one is that when four-byte addresses are inadequate, there
are compelling architectural reasons for moving to eight- and not five-,
six-. or seven-bye ones.
Those of you who have not used the 'new' 64-bit facilities need to learn
to do so. Moreover, time spent mastering them will have been used to
better advantage than time spent dismissing them as unrealistically sized.
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Kind regards,
-Steve Comstock
The Trainer's Friend, Inc.
http://www.trainersfriend.com/
John Gilmore
Ashland, MA 01721-1817
USA
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