Operating System Glossary 2

Base Address – an address that is used as the origin in the calculation of addresses in the execution of a computer program

Dynamic Relocation – a process that assigns new absolute addresses to a computer program during execution so that the program may be executed from a different area of main storage

Indexed Access – pertaining to the organization and accessing of the records of a storage structure through a separate index to the locations of the stored records

Indexed Sequential Access – pertaining to the organization and accessing of the records of a storage structure through an index of the keys that are stored in arbitrarily partitioned sequential files

Last In First Out (LIFO) – a queuing technique in which the next item to be retrieved is the item most recently placed in the queue

Logical Address – a reference to a memory location independent of the current assignment of data to memory.  A translation must be made to a physical address before the memory access can be achieved.

Memory Partitioning – the subdividing of storage into independent sections

Page – in virtual storage, a fixed length block that has a virtual address and that is transferred as a unit between main memory and secondary memory

Page Fault – occurs when the page containing a referenced word is not in main memory.  This causes an interrupt and requires that the proper page be brought into main memory.

Paging – the transfer of pages between main memory and secondary memory

Physical Address – the absolute location of a unit of data in memory (e.g., word or byte in main memory, block on secondary memory)

Real-Time System – an operating system that must schedule and manage real-time tasks

Sequential Access – the capability to enter data into a storage device or a data medium in the same sequence as the data are ordered or to obtain data in the same order as they were entered

Sequential File – a file in which records are ordered according to the values of one or more key fields and processed in the same sequence from the beginning of the file

Server – (1) a process that responds to request from clients via messages.  (2) In a network, a data station that provides facilities to other station; for example, a file server, a print server, a mail server.

Spooling – the use of secondary memory as buffer storage to reduce processing delays when transferring data between peripheral equipment and the processors of a computer

Trojan Horse – secret undocumented routine embedded within a useful program.  Execution of the program results in execution of the secret routine.

Trusted System – a computer and operating system that can be verified to implement a given security policy

Virtual Address – the address of a storage location in virtual storage

Virus – secret undocumented routine embedded within a useful program.  Execution of the program results in execution of the secret routine.