HP OpenVMS Alpha Version 8.3 and HP OpenVMS Version 8.3-1H1 for Integrity Servers SPD 82.35.13

•Shared page tables

•Expandable global page table

•Reserved memory registry

DECdtm Services

The DECdtm services embedded in the OpenVMS op- erating system support fully distributed databases us- ing a two-phase commit protocol. The DECdtm ser- vices provide the technology and features for distributed processing, ensuring both transaction and database in- tegrity across multiple HP resource managers. Updates to distributed databases occur as a single all-or-nothing unit of work, regardless of where the data physically re- sides. This ensures the consistency of distributed data.

DECdtm services allow applications to define global transactions that can include calls to any number of HP data management products. Regardless of the mix of data management products used, the global transac- tion either commits or aborts. OpenVMS is unique in providing transaction processing functionality with base operating system services.

DECdtm features include:

•Embedded OpenVMS system services that support the DECtp architecture, providing the features and technology for distributed transaction processing.

•Ability for multiple disjoint resources to be updated automatically. These resources can be either physi- cally disjointed on different clusters at separate sites, or logically disjointed in different databases on the same node.

•Ability to use the X/Open Distributed Transaction Processing XA interface that enables the DECdtm transaction manager to coordinate XA-compliant re- source managers (the HP DECdtm XA Veneer), and XA-compliant transaction processing systems to co- ordinate DECdtm-compliant resource managers (the DECdtm XA Gateway).

•Robust application development. Applications can be written to ensure that data is never in an incon- sistent state, even in the event of system failures.

•Ability to be called using any HP TP monitor or database product. This is useful for applications us- ing several HP database products.

Interprocess Communication

OpenVMS provides the following facilities for applica- tions that consist of multiple cooperating processes:

•Mailboxes as virtual devices that allow processes to communicate with queued messages.

•Shared memory sections on a single processor or an SMP system that permit multiple processes to access shared address space concurrently.

•Galaxywide sections on a Galaxy platform that permit multiple processes in multiple instances to access shared address space concurrently.

•Common event flags that provide simple synchro- nization.

•A lock manager that provides a more comprehen- sive enqueue/dequeue facility with multilevel locks, values, and asynchronous system traps (ASTs).

•Intracluster communication services through which two processes running on the same system or on dif- ferent OpenVMS Cluster nodes can establish a con- nection and exchange data.

•Logical names through which one process can pass information to other processes running on the same system or on different OpenVMS Cluster nodes.

•Network interprocess communication is available via TCP/IP Services and DECnet-Plus (product licenses are required).

Symmetric Multiprocessing (SMP)

OpenVMS provides symmetric multiprocessing (SMP) support for Alpha and Integrity servers multiprocessor systems. SMP is a form of tightly coupled multipro- cessing in which all processors perform operations si- multaneously. All processors perform operations in all OpenVMS access modes, user, supervisor, executive, and kernel.

OpenVMS SMP configurations consist of multiple CPUs executing code from a single shared memory address space. Users and processes share a single copy of OpenVMS for Integrity servers or OpenVMS Alpha ad- dress space. SMP also provides simultaneous shared access to common data in global sections to all proces- sors. OpenVMS SMP selects the CPU where a process will run based on its priority and in special cases as di- rected by the application. OpenVMS uses a specialized scheduling algorithm when running a nonuniform mem- ory access (NUMA) platform.

SMP support is an integral part of OpenVMS and is provided to the user transparently. Because an SMP system is a single system entity, it is configured into a network and OpenVMS Cluster configurations as a single node.

The maximum number of supported CPUs in an SMP configuration is 32.

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HP OpenVMS I64 Operating Systems manual DECdtm Services, Interprocess Communication, Symmetric Multiprocessing SMP
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OpenVMS I64 Operating Systems specifications

HP OpenVMS I64 is a robust operating system originally developed by Digital Equipment Corporation and later acquired by Hewlett-Packard. It stands for "Open Virtual Memory System" and is designed to run on Intel Itanium (I64) architecture, offering high reliability and performance for mission-critical applications.

One of the defining features of OpenVMS is its focus on availability and fault tolerance. It supports clustering, allowing multiple nodes to function together as a single system. This feature ensures that if one node fails, others can continue processing, minimizing downtime. Furthermore, OpenVMS employs a sophisticated method of process management, enabling the efficient handling of multiple tasks and processes simultaneously.

Security is a paramount characteristic of OpenVMS. The system implements a multi-layered security architecture, encompassing user authentication, access controls, and logging features that protect against unauthorized access. It also offers role-based access control, which streamlines permissions and bolsters overall system security.

OpenVMS is compatible with various programming languages and development tools, which makes it a versatile choice for developers. It supports languages like C, C++, COBOL, and Pascal, as well as development environments that facilitate the creation of sophisticated applications. Its comprehensive suite of development and debugging tools enhances productivity and ease of use for software engineers.

Another notable feature is its support for legacy applications. OpenVMS provides compatibility with older systems, allowing organizations to modernize their infrastructure without losing valuable investments in legacy code. This backward compatibility is vital for enterprises that require long-term system integrity and data consistency.

The operating system also features an advanced file system known as the Virtual Memory System (VMS) file system, which supports a variety of file types and efficient data management. The system is designed for high-performance I/O operations, which is crucial for applications that require quick data access and processing.

In terms of networking, OpenVMS supports a range of communication protocols, making it suitable for integration into complex networked environments. Its TCP/IP stack enables seamless connectivity with other platforms, facilitating collaboration in mixed environments.

Overall, HP OpenVMS I64 stands out for its reliability, security, and performance, making it an ideal choice for enterprises demanding a robust operating environment capable of handling their critical workloads. Its combination of advanced features and software support ensures that organizations can continue to innovate while relying on a stable foundation.
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