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Random access (also called direct access) is the ability to access an arbitrary element of a sequence in equal time or any datum from a population of addressable elements roughly as easily and efficiently as any other, no matter how many elements may be in the set. In computer science it is typically contrasted to sequential access which ...
Sequential access compared to random access. Sequential access is a term describing a group of elements (such as data in a memory array or a disk file or on magnetic-tape data storage) being accessed in a predetermined, ordered sequence. It is the opposite of random access, the ability to access an arbitrary element of a sequence as easily and ...
Basic Direct Access Method, or BDAM is an access method for IBM's OS/360 and successors computer operating systems on System/360 and later mainframes. BDAM "consists of routines used in retrieving data from, and storing data onto, direct access devices." [1]: p.5 BDAM is available on OS/360, OS/VS2, MVS, z/OS, and related high-end operating ...
Non-Shared Resources (NSR), which is optimised for sequential access. NSR access has historically been easier to use than LSR for batch programs. [12] Distributed File Management (DFM), an implementation of a Distributed Data Management Architecture server, enables programs on remote computers to create, manage, and access VSAM files.
Second, a type system for nestable skeletons which is proven to guarantee subject reduction properties and is implemented using Java Generics. [9] Third, a transparent algorithmic skeleton file access model, which enables skeletons for data intensive applications. [10] Skandium is a complete re-implementation of Calcium for multi-core computing.
Concurrent data structures are significantly more difficult to design and to verify as being correct than their sequential counterparts. The primary source of this additional difficulty is concurrency, exacerbated by the fact that threads must be thought of as being completely asynchronous: they are subject to operating system preemption, page faults, interrupts, and so on.
An access method is a function of a mainframe operating system that enables access to data on disk, tape or other external devices. Access methods were present in several mainframe operating systems since the late 1950s, under a variety of names; the name access method was introduced in 1963 in the IBM OS/360 operating system. [ 1 ]
In IBM mainframe operating systems, Queued Sequential Access Method (QSAM) [1] is an access method to read and write datasets sequentially. QSAM is available on OS/360 , OS/VS2 , MVS , z/OS , and related operating systems.