cml8@robin.cs.uofs.edu (Chris M. Little) (03/20/91)
I was discussing with a friend the possibility of a single Ada program spawning its tasks over many hosts on the Internet or any other network or subnet. We have about 30 Sun 4 Workstations in our department. I have an account on all of them. If I had a huge Ada program which utilized multi-tasking, I would like for the workload to be shared by all of them, and not just one. Has anyone else entertained this concept and/or does anyone know of an Ada package that might support this? Any insight on the issue would be welcome. -- Chris Little, Graduate Asstistant - CML8@JAGUAR.UOFS.EDU (VMS) Department of Computing Sciences - CML8@SCRANTON.BITNET (VMS) University of Scranton, Pennsylvania. - CML8@ROBIN.CS.UOFS.EDU (UNIX)
rharwood@east.pima.edu (03/23/91)
In article <366@platypus.uofs.edu>, cml8@robin.cs.uofs.edu (Chris M. Little) writes: > I was discussing with a friend the possibility of a single Ada program spawning > its tasks over many hosts on the Internet or any other network or subnet. We > have about 30 Sun 4 Workstations in our department. I have an account on all > of them. If I had a huge Ada program which utilized multi-tasking, I would > like for the workload to be shared by all of them, and not just one. Has > anyone else entertained this concept and/or does anyone know of an Ada package > that might support this? Any insight on the issue would be welcome. First, your system manager should violently object to such a possibility, if it existed! <grin> But I am not aware of any current Ada compiler that allows for a single program to be written which "multi-tasks/multi-processes" over multiple processors. I worked on a radar warning receiver which utilized 3 80186s running somewhat similar functions... but we had to take the approach of building a messaging system interface between the processors (we actually used FIFOs-on-a-chip) with special message structures for communicating "work tasks" and other info. As a Mac/VAX user, I'm not familiar with the UNIX interprocess communication capability other than to say I know it exists... hopefully your compiler vendor has provided a package with the interface calls "pre-coded". Ray Harwood |PO Box 18324 |Internet: rharwood@east.pima.edu Owner, Data Basix |Tucson, AZ 85731 |AppleLink: DATA.BASIX Associate Faculty, |Voice: (602)721-1988|CompuServe: 76645,1370 Pima Community College|FAX: (602)721-7240|Opinions: My own
madmats@elcgl.epfl.ch (03/25/91)
In article <366@platypus.uofs.edu>, cml8@robin.cs.uofs.edu (Chris M. Little) writes: > > I was discussing with a friend the possibility of a single Ada program spawning > its tasks over many hosts on the Internet or any other network or subnet. We > have about 30 Sun 4 Workstations in our department. I have an account on all > of them. If I had a huge Ada program which utilized multi-tasking, I would > like for the workload to be shared by all of them, and not just one. Has > anyone else entertained this concept and/or does anyone know of an Ada package > that might support this? Any insight on the issue would be welcome. > I have developped an Ada package called Distributor that enables execution of distributed Ada applications on a DECnet network. I intend to port this package to UNIX/internet by the end of this year. Of course, several instances of an Ada program have to run and make up a distributed application (actually distributing tasks over such a network would not be feasible because of data shared by tasks and access types among others. Moreover, it would require modifying an Ada compiler or run time system). The communication is based on message passing between processes, but more elaborate communication protocols may be built by extending the package. If anyone is interested, I have a draft of the paper that I intend to publish some day on this topic, and I would be glad to have anyone's comments. Mats Weber Swiss Federal Institute of Technology EPFL DI LGL 1015 Lausanne Switzerland E-mail : madmats@elcgl.epfl.ch phone : +41 21 693 52 92 fax : +41 21 693 39 09
johndoe@inmet.UUCP (johndoe ) (03/27/91)
In article <1991Mar25.150213.1@elcgl.epfl.ch> madmats@elcgl.epfl.ch writes: >In article <366@platypus.uofs.edu>, cml8@robin.cs.uofs.edu (Chris M. Little) writes: >Of course, several instances of an Ada program have to run and make up a >distributed application (actually distributing tasks over such a network would >not be feasible because of data shared by tasks and access types among others. >Moreover, it would require modifying an Ada compiler or run time system). There is the possibility of using CAIS-A (Common APSE Interface Set) technology of doing distributed computing over a single network. Currently, the CAIS-A distributed implementation is a set of interfaces that allows access to the common database through a main server coordinating activity and a set of local_servers - one per machine. For a set of client Ada programs running on different machines, communication is accomplished via CAIS-A interfaces for I/O and database access. The client programs would refer to one another, as well as to the communication gateway and channels, with entities associated with the database. This requires no changes to a compiler or run-time system for a networked Ada application. Of course, at this point, it would have to be a network of Sun3 computers, since the only currently available distribution of a CAIS-A implementation is for targeted to Sun3 architecture. And for the time being, you couldn't compile it, because the only supported compiler is made by Systeam, who are now a subsidiary of Alsys, and who don't really have a compiler product per se. However, this should be changing in the near future with a VMS version of a CAIS-A allowing distributed processing, and support for the Telesoft compiler on Sun3, and the Systeam and DEC compilers for the VAX. For more information about CAIS-A, contact me (johndoe@inmet.inmet.com), or Barry Siegel of NOSC (siegel@tecr.nosc.mil).