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

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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.

Input/Output

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.

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Contents User Environment DescriptionOctober Program Development Environment Posix Threads Library Macro CompilerLibrarian Utility HypersortSystem Management Environment DECamds HP Availability ManagerManagement Agents for OpenVMS HP OpenVMS Management StationPerformance Data Collector Enterprise Capacity and Performance AnalyzerGraphical Configuration Manager for OpenVMS Class Scheduler for CPU SchedulingSecurity Sysman OperationsHP Utility Pricing on OpenVMS for Integrity Servers Government Security RatingsInstant Capacity TiCAP Temporary iCAPPay per use Very Large Memory VLM FeaturesOperating System Environment Processes and SchedulingInterprocess Communication DECdtm ServicesSymmetric Multiprocessing SMP Terminal Server Products AlphaServersUniversal Serial Bus Support Integrity Server SystemsInput/Output Performance FeaturesExtended File Cache XFC Virtual I/O Cache Alpha onlyBusiness and Integration Technologies Disk and Tape VolumesHP Galaxy Software Architecture on OpenVMS Alpha Associated ProductsHP OpenVMS Cluster Software HP RMS Journaling for OpenVMS HP Volume Shadowing for OpenVMSHP Advanced Server for OpenVMS Alpha HP Pathworks for OpenVMS Advanced ServerHP DECnet-Plus and HP DECnet Software HP TCP/IP Services for OpenVMSHP DECram for OpenVMS Distributed Computing Environment DCE Support Conformance to StandardsSupport for OSF/Motif and X Window System Standards Standards Supported by OpenVMSNetwork Installation and Upgrade InstallationVirtual Connect Polycenter Software InstallationVirtual Media vMedia Vmsinstal Test Package and DiagnosticsWbemcim Layered Product Disk Space Requirements DECwindows Motif for OpenVMS Alpha Disk Space RequirementsDistribution Media Memory Space RequirementsDocumentation Source Listings Growth ConsiderationsOrdering Information Software Licenses Sold with System Ordering OE License UpgradesOpenVMS Alpha Ordering Information OE License Upgrade OptionsAlpha CD Media and Online Documentation OpenVMS Hardcopy Documentation SetsOpenVMS Alpha and Integrity servers Source List- ings Kit Software Product ServicesOpenVMS Alpha Software Products Library SPL CD Offerings Software LicensingProduct Name Description SPD Software License Information Alpha and Integrity serversOpenVMS Alpha License Information System Support ServicesVMS Integrity Server Systems Supported Systems SupportedTURBOchannel Bus-Based Systems Alpha Systems SupportedXMI Bus-Based Systems PCI Bus-Based SystemsModular Computing Component Dssi Bus-Based SystemsAppendix a OpenVMS for Integrity servers LAN OptionsSerial Attached Scsi SAS Storage Options Parallel Scsi Storage OptionsStorage and Network Combo Cards Tape DevicesDisks Terminals and Terminal Line InterfacesPBXRW-JC Tapes Swxna Networks Storage ServersControllers and Adapters Enterprise Storage ArraysAsynchronous Terminal Controllers Hubs and SwitchesSynchronous Controllers Graphics Options Dapba DefpaDapca DglpbCI Options Adapters and SwitchesMemory Channel Options MiscellaneousSoftware Warranty

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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