perm filename NEWLEP.TXT[DOC,AIL] blob sn#243886 filedate 1976-10-30 generic text, type C, neo UTF8
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C00002 00002	October 30, 1976		New LEAP (?)
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October 30, 1976		New LEAP (?)
Jim Low, Jerry Feldman, & Co. of the University of Rochester have rewritten
LEAP runtimes.  Several advantages are claimed:
   1. The hashing algorithm for associations has been improved so that
      the overall running speed of several programs has increased by 10-30%.
   2. More items:  the 4K restriction on the number of items has been removed.
      You can have as many as you have core for (minimum 2 words/item).
      (It is probably the case that you have to state in advance how many you
      wish to have.)
   3. Less restrictive storage allocation.  The storage for LEAP is no longer
      restricted to lie in addresses less than 128K, as was formerly the case.
   4. Items are allocated in decreasing order; some operations on sets are
      more efficient becaue of this.
   5. The user can request that all DATUM operations be checked to insure that
      the item has not been DELETEd and that the type corresponds to the type
      which the compiler expected.
   6. The warning message TWO PROGRAMS WITH ITEMS can be disabled upon request.

The following considerations apply with respect to incorporating these
modifications into Sail at Stanford A.I. lab:
   1. A new major version number and a new runtime segment (SAISG9, GLBSG9)
      would be required.  Old .REL files would need to be recompiled.
      This would affect all users of Sail, not just users of LEAP.
      (It is possible that the new version and segment may be coming shortly
      anyway, due to the addition of other major features.)
   2. It is possible that bugs in the new code would cause old programs to
      stop working.
   3. JFR is planning to graduate shortly.
   4. It is probable that the new code is somewhat larger than the old.

Please MAIL your comments and suggestions to AIL.