m362glossary Part 2 Flashcards
(330 cards)
namespace
A hierarchical partitioning of names that provides a way of uniquely identifying any name in a context such as an XML document or software application.
namespace prefix
The use of a namespace name as a qualifier for the simple name of an element or attribute, so forming an extended name.
native thread
A thread visible to the operating system and scheduled by it.
navigation (of a relation)
The ability to access the related record/entity of the given record/entity.
nested monitor lockout
A situation in which a thread T blocks or waits while holding a lock on the monitor that would enable other threads to make T progress. Thread T has therefore locked itself inside the monitor, keeping the ‘key’, i.e. the monitor’s lock.
node
See host.
nonce
A value used once to defeat replay attacks in cryptography algorithms.
non-pre-emptive multitasking
A process scheduling policy allowing a process to run to completion before applying a selection function.
non-repeatable read
A non-repeatable read occurs if a transaction reads the same object twice during execution and finds a different value the second time, although the transaction has not changed the value in the meantime.
non-repudiation
The property of a system that prevents users from denying sending or receiving some information or performing some action.
normalised turnaround time
The value q/s, where q is the turnaround time and s is the service time.
null process
A process executed by the scheduler when no other processes are Runnable; can be used to perform housekeeping tasks or to simplify a scheduling algorithm.
object (CORBA)
In CORBA, the general term for an object within a CORBA application, incorporating user-defined client and server objects as well as those implementing standard specifications such as those contained in common services.
object adaptor
A component facilitating communication between an ORB and a CORBA servant.
Object Management Architecture (OMA)
The architecture produced by the OMG, of which CORBA is a part; described as an ‘open, vendor independent specification for an architecture and infrastructure that computer applications use to work together over networks’.
Object Management Group (OMG)
The group responsible for the Object Management Architecture (OMA).
object request broker (ORB)
Middleware that sits between the client and the objects the client wishes to invoke. The ORB is responsible for locating each object and communicating the client’s request to the object. The object carries out the request and replies.
object serialisation
The marshalling and unmarshalling of objects so that they can be sent as streams of bits across JVMs. A class whose instances may be serialised has to implement the Serializable interface.
object service (CORBA)
A general description for operations provided by objects in the context of CORBA.
object type (CORBA)
In CORBA, a type defined by an interface within a module, specifying message-passing behaviour for a class of objects in a CORBA application.
OMG Interface Definition Language (OMG IDL)
The interface definition language specified by the Object Management Group for use in CORBA. See interface definition language (IDL).
OMG Object Model
A platform-independent description of CORBA objects, operations, interfaces and types.
one-time pad
A cipher with perfect secrecy, invented in 1917.
one-to-many relation
A relationship between two tables or entity classes, in which each record or entity of the first table/class is related to zero or more records/entities of the second table/class.