dlw@talcott.harvard.edu (Dan Weinreb) (03/30/89)
I'm looking for a good lightweight process package, and would appreciate any help with the following questions: (1) Has anyone had experience with Sun's LWP library? Does it seem to work well? Did its performance seem good enough? (2) Is there any other lightweight process package available for Suns? (3) Is there any lightweight process package that runs well on a wider range of Unix platforms than just Suns? Thank you very much. Daniel Weinreb Object Design, Inc. odi!dlw@talcott.harvard.edu or uunet!odi!dlw
aarons%cogs.sussex.ac.uk@nss.cs.ucl.ac.uk (Aaron Sloman) (04/26/89)
odi!dlw@talcott.harvard.edu (Dan Weinreb, Object Design, Inc.) writes: > I'm looking for a good lightweight process package, and would appreciate > any help with the following questions: > > (1) Has anyone had experience with Sun's LWP library? Does it seem to > work well? Did its performance seem good enough? > > (2) Is there any other lightweight process package available for Suns? The Pop-11 subset of Poplog allows the creation of "lightweight" processes that can be suspended then resumed (i.e. co-routines). The process mechanism is accessible from the other Poplog languages: Prolog, Common Lisp, and ML, by calling Pop-11 procedures. > (3) Is there any lightweight process package that runs well on a wider > range of Unix platforms than just Suns? > At present Poplog runs (with all its languages, the editor, libraries, online documentation, etc.) on the following systems VAX (VMS/Unix), Sun2, Sun3, Sun4(SPARC), Sun386i (Road-runner), HP 9000 300 series workstations with HPUX Apollo with Bsd Unix Sequent Symmetry with Dynix Orion 1/05 (Unix with Clipper). This version is not supported at present, but it appears to work. ------- For example here's a little Pop-11 program that compares the "fringes" (i.e. the leaves) on two binary trees, by alternately generating one atom from each tree and stopping if they ever differ, or if they have both been exhausted. define fringe(tree); ;;; Recursive procedure to crawl round tree suspending process ;;; whenever a leaf of the tree is found. if tree = [] then return elseif atom(tree) then suspend(tree,1) else fringe(front(tree)); fringe(back(tree)) endif; enddefine; define getfringe(tree); ;;; A procedure that runs fringe, then returns -termin- if ;;; fringe ever finishes. fringe(tree); return(termin) enddefine; define samefringe(tree1, tree2); ;;; Now the procedre that takes two trees, creates a leave-generating ;;; process for each, and compares them one at a time. lvars tree1, tree2, proc1, proc2, next1, next2; consproc(tree1, 1, getfringe) -> proc1; consproc(tree2, 1, getfringe) -> proc2; repeat runproc(0, proc1) -> next1; runproc(0, proc2) -> next2; returnif(next1 /== next2)(false); returnif(next1 == termin)(true); endrepeat enddefine; ;;;Now test the procedure on two trees with the same fringe but ;;;very differnt structures. samefringe([1 [2 [3 [4]]]], [[1] 2 [[[3]]] 4 ]) => ** <true> It is also possible to implement a scheduler that interrupts and suspends processes every so often, getting a new one from a process queue each time. In fact we use this for teaching an elementary course on operating systems. For information about getting Poplog in USA and Canada contact Prof Robin Popplestone at Univ. of Massachusetts: pop@cs.umass.edu Aaron Sloman, School of Cognitive and Computing Sciences, Univ of Sussex, Brighton, BN1 9QN, England ARPANET : aarons%uk.ac.sussex.cogs@nss.cs.ucl.ac.uk aarons%uk.ac.sussex.cogs%nss.cs.ucl.ac.uk@relay.cs.net JANET aarons@cogs.sussex.ac.uk BITNET: aarons%uk.ac.sussex.cogs@uk.ac or aarons%uk.ac.sussex.cogs%ukacrl.bitnet@cunyvm.cuny.edu UUCP: ...mcvax!ukc!cogs!aarons or aarons@cogs.uucp