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Record-oriented Filesystem
In computer science, a record-oriented filesystem is a file system where data is stored as collections of records. This is in contrast to a byte-oriented filesystem, where the data is treated as an unformatted stream of bytes. There are several different possible record formats; the details vary depending on the particular system. In general the formats can be fixed-length or variable length, with different physical organizations or padding mechanisms; metadata may be associated with the file records to define the record length, or the data may be part of the record. Different access methods for records may be provided, for example records may be retrieved in sequential order, by key, or by record number. Origin and characteristics Record-oriented filesystems are frequently associated with mainframe operating systems, such as OS/360 and successors and DOS/360 and successors, and midrange operating systems, such as RSX-11 and VMS. However, they originated earlier in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COMMONNAME
A common name, in the nomenclature of biology, is a name of a taxon or organism based on the normal language of everyday life. Common name may also refer to: * Common name (chemistry) (also: trivial name), non-systematic name for a chemical * Common noun in linguistics, noun that refers to a class of entities rather than a unique entity * CN (or "common name") in cryptography, part of an X.509 attribute certificate See also * Generic name (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unit Record Equipment
Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using Electromechanics, electromechanical machines collectively referred to as unit record equipment, electric accounting machines (EAM) or tabulating machines. Unit record machines came to be as ubiquitous in industry and government in the first two-thirds of the twentieth century as computers became in the last third. They allowed large volume, sophisticated data-processing tasks to be accomplished before electronic computers were invented and while they were still in their infancy. This data processing was accomplished by processing punched cards through various unit record machines in a carefully choreographed progression. This progression, or flow, from machine to machine was often planned and documented with detailed flowcharts that used standardized symbols for documents and the various machine functions. All but the earliest machines had high-speed me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Data Management Architecture
Distributed Data Management Architecture (DDM) is IBM's open, published software architecture for creating, managing and accessing data on a remote computer. DDM was initially designed to support record-oriented files; it was extended to support hierarchical directories, stream-oriented files, queues, and system command processing; it was further extended to be the base of IBM's Distributed Relational Database Architecture (DRDA); and finally, it was extended to support data description and conversion. Defined in the period from 1980 to 1993, DDM specifies necessary components, messages, and protocols, all based on the principles of object-orientation. DDM is not, in itself, a piece of software; the implementation of DDM takes the form of client and server products. As an open architecture, products can implement subsets of DDM architecture and products can extend DDM to meet additional requirements. Taken together, DDM products implement a distributed file system. Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VSAM
Virtual Storage Access Method (VSAM) 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. Originally a record-oriented filesystem, VSAM comprises four data set ''organizations'': key-sequenced (KSDS), relative record (RRDS), entry-sequenced (ESDS) and linear (LDS). The KSDS, RRDS and ESDS organizations contain records, while the LDS organization (added later to VSAM) contains a sequence of pages with no intrinsic record structure, for use as a memory-mapped file. Overview An IBM ''Redbook'' named "VSAM PRIMER" (especially when used with the "Virtual Storage Access Method (VSAM) Options for Advanced Applications" manual) explains the concepts needed to make use of VSAM. IBM uses the term ''data set'' in official documentation as a synonym for ''file'', and ''direct-access storage dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISAM
Indexed Sequential Access Method (ISAM) is a method for creating, maintaining, and manipulating computer files of data so that records can be retrieved sequentially or randomly by one or more keys. Indexes of key fields are maintained to achieve fast retrieval of required file records in indexed files. IBM originally developed ISAM for mainframe computers, but implementations are available for most computer systems. The term ''ISAM'' is used for several related concepts: *The IBM ISAM product and the algorithm it employs. *A database system where an application developer directly uses an application programming interface to search indexes in order to locate records in data files. In contrast, a relational database uses a query optimizer which automatically selects indexes. *An indexing algorithm that allows both sequential and keyed access to data. Most databases use some variation of the B-tree for this purpose, although the original IBM ISAM and VSAM implementations did not d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMS File System
CMS may refer to: Computing * Call management system * CMS-2, a programming language implemented for and used by the United States Navy * Code Morphing Software, a technology used by Transmeta * Collection management system for a museum collection * Color management system, a system for computers to control the representation of colors * Concurrent mark sweep collector, a garbage collector in the Oracle HotSpot Java virtual machine * Configuration management system * Construction and management simulation, a type of simulation video game * Contact management system, an integrated office solution to record relationships and interactions with customers and suppliers * Content management system, a system for managing content and providing it in various formats * Conversational Monitor System, previously Cambridge Monitor System, an IBM mainframe operating system, also known as VM/CMS and CP/CMS * Course management system, software that facilitates e-learning or computer l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Files-11
Files-11 is the file system used in the RSX-11 and OpenVMS operating systems from Digital Equipment Corporation. It supports record-oriented I/O, remote network access, and file versioning. The original ODS-1 layer is a flat file system; the ODS-2 version is a hierarchical file system, with support for access control lists,. Files-11 is similar to, but significantly more advanced than, the file systems used in previous Digital Equipment Corporation operating systems such as TOPS-20 and RSTS/E. History The native OpenVMS file system is descended from older DEC operating systems and is similar in many ways, both having been designed by Dave Cutler. A major difference is the layout of directories. These file systems all provided some form of rudimentary non-hierarchical directory structure, typically based on assigning one directory per user account. Under RSTS/E, each user account was represented by two numbers, a 'project'',''programmer''/code> pair, and had one associ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Set (IBM Mainframe)
In the context of IBM mainframe computers in the S/360 line, a data set (IBM preferred) or dataset is a computer file having a record-oriented file, record organization. Use of this term began with, e.g., DOS/360, OS/360, and is still used by their successors, including the current z/OS. Documentation for these systems historically preferred this term rather than ''computer file, file''. A data set is typically stored on a direct access storage device (DASD) or magnetic tape, however unit record devices, such as punch card readers, card punches, line printers and page printers can provide input/output (I/O) for a data set (file). Data sets are not unstructured streams of bytes, but rather are organized in various logical record and block structures determined by the DSORG (data set organization), RECFM (record format), and other parameters. These parameters are specified at the time of the data set allocation (creation), for example with Job Control Language DD statements. Withi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream (computing)
In computer science, a stream is a sequence of potentially unlimited data elements made available over time. A stream can be thought of as items on a conveyor belt being processed one at a time rather than in large batches. Streams are processed differently from batch data. Normal functions cannot operate on streams as a whole because they have potentially unlimited data. Formally, streams are '' codata'' (potentially unlimited), not data (which is finite). Functions that operate on a stream producing another stream are known as filters and can be connected in pipelines in a manner analogous to function composition. Filters may operate on one item of a stream at a time or may base an item of output on multiple items of input such as a moving average. Examples The term "stream" is used in a number of similar ways: * "Stream editing", as with sed, awk, and perl. Stream editing processes a file or files, in-place, without having to load the file(s) into a user interface. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carriage Return
A carriage return, sometimes known as a cartridge return and often shortened to CR, or return, is a control character or mechanism used to reset a device's position to the beginning of a line of text. It is closely associated with the line feed and newline concepts, although it can be considered separately in its own right. Typewriters Originally, the term "carriage return" referred to a mechanism or lever on a typewriter. For machines where the type element was fixed and the paper held in a moving ''carriage'', this lever was on the left attached to the moving carriage, and operated after typing a line of text to cause the carriage to return to the far right so the type element would be aligned to the left side of the paper. The lever would also usually ''feed'' the paper to advance to the next line. Many electric typewriters such as IBM Electric or Underwood Electric made carriage return to be another key on the keyboard instead of a lever. The key was usually labeled "car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delimiter
A delimiter is a sequence of one or more Character (computing), characters for specifying the boundary between separate, independent regions in plain text, Expression (mathematics), mathematical expressions or other Data stream, data streams. An example of a delimiter is the comma character, which acts as a ''field delimiter'' in a sequence of comma-separated values. Another example of a delimiter is the time gap used to separate letters and words in the transmission of Morse code. In mathematics, delimiters are often used to specify the scope of an Operation (mathematics), operation, and can occur both as isolated symbols (e.g., Colon (punctuation), colon in "1 : 4") and as a pair of opposing-looking symbols (e.g., Angled bracket, angled brackets in \langle a, b \rangle). Delimiters represent one of various means of specifying boundaries in a data stream. String literal#Declarative notation, Declarative notation, for example, is an alternate method (without the use of delimiter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newline
A newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a sequence of characters, is used to signify the end of a line (text file), line of text and the start of a new one. History In the mid-1800s, long before the advent of teleprinters and teletype machines, Morse code operators or telegraphists invented and used Prosigns for Morse code, Morse code prosigns to encode white space text formatting in formal written text messages. In particular, the International Morse code, Morse prosign (mnemonic break text), represented by the concatenation of literal textual Morse codes "B" and "T" characters, sent without the normal inter-character spacing, is used in Morse code to encode and indicate a ''new line'' or ''new section'' in a formal text message. Later, in the age of modern teleprinters, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
