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Virtual Storage Access Method (VSAM) [1] is an IBM direct-access storage device (DASD) file storage access method, first used in the OS/VS1, OS/VS2 Release 1 (SVS) and Release 2 (MVS) operating systems, later used throughout the Multiple Virtual Storage (MVS) architecture and now in z/OS.
IDCAMS ("Access Method Services") generates and modifies Virtual Storage Access Method (VSAM) and Non-VSAM datasets. IDCAMS was introduced along with VSAM in OS/VS; the "Access Method" reference derives from the initial "VSAM replaces all other access methods" mindset of OS/VS. IDCAMS probably has the most functionality of all the utility ...
A process can store data in memory-mapped files on memory-backed file systems, such as the tmpfs file system or file systems on a RAM drive, and map files into and out of the address space as needed. A set of processes may still depend upon the enhanced security features page-based isolation may bring to a multitasking environment.
In 1972 IBM announced the first release of the OS/VS2 operating system for the IBM System 370 systems; that release later was known as Single Virtual Storage . In 1974 IBM announced release 2.0; that release and all subsequent releases became known as Multiple Virtual Storage . All releases of OS/VS2 were available to no charge because the ...
Multiple Virtual Storage, more commonly called MVS, is the most commonly used operating system on the System/370, System/390 and IBM Z IBM mainframe computers. IBM developed MVS, along with OS/VS1 and SVS, as a successor to OS/360. It is unrelated to IBM's other mainframe operating system lines, e.g., VSE, VM, TPF.
OS/360, officially known as IBM System/360 Operating System, [1] [2] is a discontinued batch processing operating system developed by IBM for their then-new System/360 mainframe computer, announced in 1964; it was influenced by the earlier IBSYS/IBJOB and Input/Output Control System (IOCS) packages for the IBM 7090/7094 [citation needed] and even more so by the PR155 Operating System for the ...
For example, if a file server has a number of hard drives that are only partially filled, file-based virtualization can be used to store files on those drives, thereby increasing the utilization of the storage devices. File-based virtualization can be used to create a virtual file server (or virtual NAS device), which is a storage system that ...
A portion of the computer main memory can be set up as a RAM disk that serves as a storage device for a file system. File systems such as tmpfs can store files in virtual memory. A virtual file system provides access to files that are either computed on request, called virtual files (see procfs and sysfs), or are mapping into another, backing ...