Software Product Description ___________________________________________________________________ PRODUCT NAME: DEC Distributed Computing Services SPD 43.11.01 for OpenVMS, Version 1.0 DESCRIPTION The DEC Distributed Computing Services (DECdcs) software integrates remote OpenVMS AXP (AXP) compute server systems into the OpenVMS VAX (VAX) computing environment. It extends the OpenVMS VAX environment to control jobs executing on remote OpenVMS AXP compute servers. The DECdcs software provides: o VAX users and applications with the capability to submit jobs to remote AXP compute servers via familiar OpenVMS batch commands o Remote interactive access to server applications that use DECwin- dows (or X Windows) to display back onto the client o Synchronization with the jobs on the compute servers via standard OpenVMS batch synchronization techniques (e.g., the DCL command SYN- CHRONIZE) o A high degree of compatibility with other OpenVMS batch mechanisms, so that the jobs seem like normal jobs to OpenVMS users o Systems and applications programmers with the tools to "hide" the remote system from the OpenVMS end user-the VAX end user can ac- cess the compute power of the remote AXP systems without being aware that the server is another node o Sharing of a single AXP compute server among a number of OpenVMS systems or VMSclusters o Use of a number of servers from a single OpenVMS system or VMSclus- ter DIGITAL January 1993 DECdcs uses DECnet to communicate with remote AXP servers. All job and control information passes between the local VAX client and the re- mote AXP server via the network connection; no other optional soft- ware is required for DECdcs operation. Data and file sharing between the clients and remote servers depends on the nature and design of the application that is sent to the server. The choice of file sharing method is part of the application design process. The system manager can designate the number of job streams to allow per client or server system, so that servers of varying capacity can be accommodated. In addition, job limits can be placed on the clients. This provides the ability to ensure equitable sharing of a server among multiple client systems-no single client system will be allowed to mo- nopolize all of the job slots on the server system. Features The most important feature of the DECdcs software is its ability to allow a VAX user to use local OpenVMS commands to execute a job on a remote compute server. To the OpenVMS end user, the job appears to be executing on the local VAX system or VMScluster. The fact that most of the existing OpenVMS batch features are avail- able to the DECdcs user means that applications can be built to in- tegrate the best features of OpenVMS and the remote systems. For ex- ample, an OpenVMS job running on a VAXstation could consolidate data, dispatch a compute-intensive processing phase to an AXP server, and then wait for the remote phase to complete, before continuing with the rest of the job on the local workstation. It is also possible for OpenVMS application programs to create jobs on remote systems by calling DECdcs through the $SNDJBC system ser- vice programming interface to the OpenVMS batch system. This service allows an OpenVMS program to create jobs, and other system service calls to allow the program to monitor the progress of the job-for example, to wait for its completion. Interactive Remote Programs 2 Through the client/server split inherent in DECwindows, it is possi- ble to use DECdcs to integrate interactive remote applications with a local workstation. A user on a VAXstation can easily initiate a re- mote job that will use the VAXstation's display for a remote AXP job's interactive input and output. These features can be used to create applications where the user is unaware that certain functions are done on VAX systems, and other func- tions are handled by remote AXP systems. For example, an OpenVMS DECwin- dows application could be written so that a click on a menu item on the VAXstation could cause a DECdcs remote job to be started on the server. That remote job would execute on a remote AXP compute server, and then create a window back on the VAXstation-and the end user would not even be aware that the window actually came from a job running on the AXP server. The user simply selects a menu item, and a window appears on his/her VAXstation. OpenVMS Programming The VAX user or application submits a standard DCL command procedure to the queue controlled by the DECdcs software. Because this proce- dure executes in the environment of the AXP server system, certain guide- lines should be followed by this command procedure, as described in the DECdcs User's Manual. This may require some changes to local com- mand procedures, so that they will operate correctly on the remote sys- tem. File and Data Sharing File access and sharing are done according to application needs. The programmer decides on an appropriate model for sharing information be- tween the OpenVMS VAX system and the remote server: o Use DECnet remote file access to allow the AXP jobs to read and write the files on the VAX client system 3 o Copy files from the client system to the remote system (e.g., us- ing RMS with DECnet or the DCL command COPY) and process them on local disks on the server machine, and then copy output files back to the client o Maintain files on local storage on the remote server system and do only local processing o Any combination of these methods The choice of file access method will be determined by application de- sign and local configuration and network load. For example, if the ap- plication performs heavy I/O to an exclusively accessed file, then it may be desirable to place that file on local storage during the run. DECdcs provides what is basically a production environment so that re- mote applications can be controlled by OpenVMS users. DECdcs does not provide an extended development environment, although the DECdcs en- vironment could be used for program development. Most likely, however, the application developer would want to use the normal interactive en- vironment and tools available on the server system to develop the ap- plications. Security The DECdcs software maintains a database to determine which VAX client systems are allowed to interact with which remote AXP servers. This password-protected database helps ensure that only authorized nodes are permitted to send jobs to the compute servers. Standard OpenVMS security mechanisms, such as Access Control Lists on the DECdcs queues, can be used to restrict access to authorized in- dividuals on the client system. Other users would be prevented from sending jobs to the system. The security for shared files is provided by the network file access protocols of DECnet. 4 DECdcs maintains an outbound proxy database on the client system. This allows a user to have different usernames on the client and server sys- tems. It also permits the system manager of the client system to des- ignate a single username on the remote system for certain groups to share, without requiring the manager of the server system to be in- volved. On the server system, DECdcs maintains an inbound proxy database. DECdcs will not run a user job unless it finds a proxy entry covering that user. Wildcard proxy entries can be used to map entire client systems, or to specify that a job should run under the same username on the server system as on the client. A privileged job will not be run unless the system manager on the server system specifies that a certain user be permitted to run with privileges-wildcard entries will not permit priv- ileged jobs to run. The system manager of the server system can spec- ify the set of privileges that are allowed for wildcard entries. HARDWARE REQUIREMENTS The client components of DECdcs can be installed on any OpenVMS VAX processor or configuration as specified in the System Support Adden- dum (SSA 43.11.01-x). The server components of DECdcs can be installed on any OpenVMS AXP system or server configuration as specified in the System Support Ad- dendum (SSA 43.11.01-x). The client and server must have network connections to each other. Usu- ally, they would be on the same local area network. The DECdcs soft- ware will work over wide area network connections, but the lower band- width typical of wide area networks would have to be considered in the application design. 5 SOFTWARE REQUIREMENTS For Client Systems: OpenVMS VAX Operating System DECnet/OSI for OpenVMS VAX For Server Systems: OpenVMS AXP Operating System DECnet for OpenVMS AXP Refer to the System Support Addendum (SSA 43.11.01-x) for availabil- ity and required versions of prerequisite/optional software. ORDERING INFORMATION OpenVMS VAX-Based Client Systems Client Software Licenses: QL-07NAA-3B Software Update Service: QT-07NAA-DB OpenVMS AXP-Based Server Systems Server Software Licenses: QL-07PA*-AA Software Update Service: QT-07PA*-L9 * Denotes variant fields. For additional information on available li- censes, refer to the appropriate price book. General Media (TK50)* & Documentation: QA-07NAA-H5 Media & Documentation Service: QT-07NAA-E5 Digital CD-ROM Software Library for OpenVMS AXP: QA-03XAA-HA Software Documentation: QA-07NAA-GZ Documentation Support Service: QT-07NAA-KZ * Either media kit contains both the client and server software mod- ules. 6 SOFTWARE LICENSING This software is furnished under the licensing provisions of Digital Equipment Corporation's Standard Terms and Conditions. DECdcs consists of client and server software modules. Both modules are licensed. A client license enables a client connection to remote servers and con- trols the number of concurrent jobs that a client will allow. A sin- gle client license consists of eight units. Each client/server con- nection consumes three units. Each job dispatched to a server requires one unit to run. Hence, a single client license allows a single server connection plus the ability to run five concurrent jobs. Alternatively, it allows two server connections and two concurrent jobs. Purchasing extra client licenses will extend the number of server connections and /or the number of jobs. A server license is required to enable client connection to the server. The server license purchased must match the machine type on which the DECdcs server software will run. Up to eight client systems are al- lowed per server process. The number of jobs issued to the server is controlled via the client licenses. For more information about Digital's licensing terms and policies, con- tact your local Digital office. SOFTWARE WARRANTY Warranty for this software product is provided by Digital with the pur- chase of a license for the product as defined in the Software Warranty Addendum of this SPD. [R] PostScript is a registered trademark of Adobe Systems Inc. 7 [TM]The DIGITAL Logo, Alpha AXP, AXP, Bookreader, CI, DEC, DECnet, DECwindows, Digital, MicroVAX, OpenVMS, TK, VAX, VAXcluster, VAXft, VAXserver, VAXstation, and VMScluster are trademarks of Digital Equipment Corporation. 8