Input/Output

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

•Memory errors. These can be unrecoverable (hard) errors or recoverable (soft) errors. The system ex- amines memory at startup time and does not use any bad pages. During system operation, the system cor- rects all single-bit memory errors for those systems with error correction code (ECC) memory.

•Correctible memory errors. A primary cause of these correctible memory errors is alpha particle radi- ation. On some processors, when correctible mem- ory errors occur, the memory controller corrects only the data returned to the CPU or I/O controller. The actual data in memory is left with the error intact. Subsequent read operations cause correction cycles to occur and, in most cases, an interrupt to report the error. On many of these processors, OpenVMS monitors the occurrence of correctible memory errors and, in almost all cases, is able to remove the error condition by rewriting the data in memory. Rewrit- ing the data causes the data to be corrected in that memory location.

Other failures include:

•Operating system errors (system-detected inconsis- tencies or architectural errors in system context)

•User errors

•I/O errors

The system logs all processor errors, all operating system errors detected through internal consistency checks, all double-bit memory errors (and a summary of corrected single-bit memory errors), and most I/O er- rors.

If the system is shut down because of an unrecoverable hardware or software error, a dump of physical mem- ory is written. The dump includes the contents of the processor registers. The OpenVMS System Dump An- alyzer (SDA) utility is provided for analyzing memory dumps.

The QIO system service and other related I/O services provide a direct interface to the operating system’s I/O routines. These services are available from within most OpenVMS programming languages and can be used to perform low-level I/O operations efﬁciently with a mini- mal amount of system overhead for time-critical appli- cations.

Device drivers execute I/O instructions to transfer data to and from a device and to communicate directly with an I/O device. Each type of I/O device requires its own driver. HP supplies drivers for all devices supported by the OpenVMS operating system and provides QIO system service routines to access the special features available in many of these devices.

OpenVMS supports a variety of disk and tape periph- eral devices, as well as terminals, networks, and mail- boxes (virtual devices for interprocess communication), and more general I/O devices.

I/O Performance Features

Fast I/O provides a suite of additional system services that applications can use to improve I/O throughput. The fast I/O services minimize the CPU resources required to perform I/O.

Fast Path provides a streamlined mainline code path through the I/O subsystem to improve both uniproces- sor and multiprocessor I/O performance. On multipro- cessor systems, Fast Path allows all CPU processing for speciﬁc I/O adapters to be handled by a speciﬁc CPU. This can signiﬁcantly lower the demands on the primary CPU and increase the I/O throughput on multiproces- sor systems with multiple I/O ports. No user application changes are needed to take advantage of Fast Path. Fast Path can be utilized by the $QIO system service or the Fast I/O services.

Extended File Cache (XFC)

The Extended File Cache (XFC) is a virtual block data cache provided with OpenVMS Alpha and OpenVMS for Integrity servers. Similar to the Virtual I/O Cache, the XFC is a clusterwide, ﬁle system data cache. Both ﬁle system data caches are compatible and coexist in the OpenVMS Cluster.

The XFC improves I/O performance with the following features that are not available with the virtual I/O cache:

•Read-ahead caching

•Automatic resizing of the cache

•Larger maximum cache size

•No limit on the number of closed ﬁles that can be cached

•Control over the maximum size of I/O that can be cached

•Control over whether cache memory is static or dy- namic

Virtual I/O Cache (Alpha only)

OpenVMS Alpha provides a standalone or clusterwide, ﬁle-oriented disk cache. Applications beneﬁt from the advantages of the virtual I/O cache without any special coding. The virtual I/O ﬁle-caching algorithm is chosen based on the type of clusterwide access currently in progress. Virtual I/O caching reduces current and po- tential I/O bottlenecks within OpenVMS systems. It re- duces the number of I/Os to the disk subsystem, thereby reducing systemwide bottlenecks.

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.

HP OpenVMS I64 Operating Systems Input/Output, Performance Features, Extended File Cache XFC

Models: OpenVMS I64 Operating Systems