Computer Aptitude

LANs can be connected by devices called bridges, which operate in the Data Link Layer.

The Histogram shows the total tonal distribution in the image. It's a barchart of the count of pixels of every tone of gray that occurs in the image. It helps us analyze, and more importantly, correct the contrast of the image.

The presentation layer formats the data to be presented to the application layer. It can be viewed as the translator for the network. This layer may translate data from a format used by the application layer into a common format at the sending station then translate the common format to a format known to the application layer at the receiving station.The presentation layer provides character code translation: for example, ASCII to EBCDIC.

There is a distinction, although sometimes subtle, between the abstract data type and the data structure used in its implementation. For example, a List ADT can be represented using an array-based implementation or a linked-list implementation. A List is an abstract data type with well-defined operations (add element, remove element, etc.) while a linked-list is a pointer-based data structure that can be used to create a representation of a List. The linked-list implementation is so commonly used to represent a List ADT that the terms are interchanged and understood in common use.

FTP uses one connection for commands and the other for sending and receiving data. FTP has a standard port number on which the FTP server listens for connections. A port is a logical connection point for communicating using the Internet Protocol (IP). The standard port number used by FTP servers is 21 and is used only for sending commands. Since port 21 is used exclusively for sending commands, this port is referred to as a command port. For example, to get a list of folders and files present on the FTP server, the FTP Client issues a LIST command. The FTP server then sends a list of all folders and files back to the FTP Client. The port that is used for transferring data is referred to as a data port.

The C shell is a C-type shell. Here, the default prompt is the % character.

The standard output of one command may be connected to the standard input of another by writing the 'pipe' operator, indicated by |, as in, ls -l | wc.

To verify that a fixed bug has not  resulted in another functionality or business rule violation Regression testing is used. The intent of Regression testing is to ensure that a change, such as a bug fix did not result in another fault being uncovered in the application.

Real-time operating systems are used to control machinery, scientific instruments and industrial systems. An RTOS typically has very little user-interface capability, and no end-user utilities, since the system will be a sealed box when delivered for use. A very important part of an RTOS is managing the resources of the computer so that a particular operation executes in precisely the same amount of time, every time it occurs.

Deadlock involves in-definite waiting as a deadlock is a situation when a process in the system has acquired some resources and waiting for more resources, which are acquired by some other process and in turn is waiting for the resources acquired by this process. Hence, none of them can proceed and OS can not do any work.

Break even analysis is an analysis to determine the point at which revenue received equals the costs associated with receiving the revenue. This analysis is carried out during the feasibility study.

Dispatch latency is the amount of time required for the scheduler to stop one process and start another.

Binary Synchronous Communication (BSC or Bisync) is an IBM character-oriented, half-duplex link protocol.

HIPPI (High-Performance Parallel Interface) is a standard point-to-point protocol for transmitting large amounts of data at up to billions of bits per second over relatively short distances, mainly on local area networks ( LAN s).

The network layer controls the operation of the subnet deciding,  which physical path the data should take based on network conditions, priority of service, and other factors. Congestion control is a feature of this layer. Leaky Bucket is a congestion control algorithm often used in this layer.