What do you know about DIR/S command ?

This command is used to display files and all files in subdirectories under the current directory.

What do you know about DIR command?

DIR command is used to display files and subdirectories under the current directory.

What is Project Management?


Handles and coordinates large projects also used to identify critical activities and tasks that could delay or jeopardise an entire project if they are not completed in a finely and cost effective fashion.

What is fast speed in modern computers?


Modern computers use more than one processor to increase the speed of the system. Processors cooperate among themselves to solve a single process or they may execute multiple process simultaneously. Parallel processing requires special operating system to schedule multiple processes. UNIX, LINUX etc. have parallel processing features.

What is High Reliability in modern computers?


Modern computers use multiple units that does the same function. These multiple functional units may work simultaneously resulting in higher throughput. Such systems improves the reliability because even if there is a failure of one or more units, the system can continue to function but with a less throughput. Thus the entire system will not be down. Many servers use this technique. There will be more than one server running in parallel. Output from only one will be considered. In case there is a failure of one server another server automatically take over.

What are small size modern computers?


Great development that took place in the field of semiconductor technology resulted in the reduction of size of modern computers. With the development of transistors the size of computer came down from room size to shelf size. Later on with the development of IC technology computer size shrinked to box size. With further development of single chip CPU with VLSI technology, further reduction in size of computers became possible. Now with the latest ultra large scale integrated circuits, entire CPU, memory and I/O ports and other semiconductor devices like timers, ADC, DAC etc. Can be integrated into single chip resulting in design of palm top computers.

What is Multitasking OS?


A multitasking OS allow a user to perform more than one computer task such as the operation of an application program at atime. The operating system is able to keep track of where the control is in these tasks and go from one to another without loosing information. When some one open a web browser and then open say word, at the same time, he is causing the OS to do multitasking. A time shared OS allow multiple users to use the same system at the same time. This is the main advantage of multi user operating system. Thus resources can be shared also.

What is Time Sharing OS?


In this type of OS , multiple users can use the same computer. User programs are loaded into computer memory and CPU is switched rapidly between user programs, giving each user the impression that computer is attending to His/her programs.

What is Compact Disk?


It is made from a 1.2 mm thick disk of pure poly carbonate plastic. Data is recorded in its surface on one side in the form of pits and lands which represents zeros and ones. A 12cm standard CD can store 650-703 MB of data.

What is Magnetic Tape?

It is sequential storage medium. It include a thin magnetizable coating on a long and narrow strip involving plastic. A tape drive uses correctly controlled motors to wind the tape derived from one of reel to another passing a tape head as it does the winding. Magnetic tapes that could store upto 1 TB can be found. They are generally used for back purpose. Their speed is fewer and cannot have random access of data.

What is Hard Disk?

A Hard Disk uses round flat disks called platters coated on both sides which has a special media material designed to store information available as magnetic patterns. The platters are mounted by cutting a hole from the center and stacking them onto a spindle. The platters rotate at high speed driven by a special spindle motor connected towards spindle. Data is recorded on either surface of a platter. The very best most and bottom most platters have only their inner sides recorded with data. Typical hard disk can keep upto 160 GB of files.

What is Floppy Disk?

A Floppy disk is a data storage medium that consists of a disk of thin, flexible magnetic storage medium encased within a square or rectangular plastic layer. The standard 3/1 inch high density floppy can be used to store 1. 44 mb of data. There are many high capacity floppy disk that may store upto 200 mb of data. Floppy disks are becoming more and more unpopular because of unreliability of the device.

What is a Program?

A Program is a collection of instructions that the computer follows to try and do a specific job. As an average user of operating system we've got many standard programs and methods available.

What is Shell?

The shell is a program that executes the codes types by user at terminal. It is also known as command interpreter. It act like a mediator which interpret the commands that user gives after which conveys them to the kernal which in turn ultimately executes them. The shell program is responsible for displaying a prompt on the screen and interpreting commands. These commands might be typed at the keyboard or stored in the file.

What is Kernel?

The centre of UNIX operating system is the kernel. The kernel controls usage of the computer hardware and copes with the computer memory and allocates the computer resources one user then to another. It is kernel that interact with the specific HW in machine language.

What are Device Files?

They're special files associated with numerous devices. They are collectively kept beneath the 'dev' directory. They contain the device drivers and associated data associated with proper functioning of device.

What are Directory Files?

A Directory file stores information about a directory, its relationship with other directories, what files and subfiles are stored inside it and access permissions. The file is updated everytime and alteration is made to the directory, its surrounding web directories and files and subdirectories under it.

What are Ordinary Files?

These are the files that store data, such as text information and programs.

What is Interpreter?

Interpreter is a software that translate one origin instruction into object code and the computer immediately execute that instruction before moving on to translate the next instruction. Interpreted program tend to take longer time to complete execution than compiled software programs. Every time a program is usually to be executed, it is to always be translated. Interpreted are often used during the program development phase.

What is BIOS?

BIOS is Basic Input Output System. This is a collection of programs that is stored in the ROM in personal computers. They are usually driver programs for standard devices. DOS call these device driver programs to complete I/O operations.

What is Object Program?

Object Programs are programs in machine language form. Normally users write computer program using high level languages or assembly languages. If program is written in high level language, then it is to get converted to machine executable form using a Compiler. If program is prepared in assembly language, it is usually to be converted to machine executable form using an assembler. Output of compiler or even assemblers are called object program. They can be directly accomplished by machine.

What is Message Transfer Agent?


The other subsystem of e-mail system is message transfer agent. It actions messages from source to vacation spot. They are system programs that run from the background and move e-mail with the system. They establish a transport connection in the source machine to destination machine and transfer the message.

What is Mail Box?


Mail box is a provision in e-mail system to store incoming e-mail. Users can certainly inspect the contents of mail boxes and delete messages via mail boxes.

What is e-mail?


Electronic mail or e-mail is the service in computer network for sending the text document by data transmission.

What is Message?


They are information encapsulated in a frame or packet and sent from one entity to other. Receiving entity opens the packet and retrieve information from it. Communication between two distant entities are done through message passing.

What is ISP?

Interface Service Provider. The entities in a layer n interface implement a service used by layer n+1. In this case layer n interface is called interface service provider.

What is Entity?


OSI model divides a pc network into seven distinct levels. The active events in each layer will often be called entities. An entity is usually a software entity or a computer hardware entity.

What is meant by the Term System? What are the characteristics and categories of information system?


A system is an orderly grouping regarding independant components linked together based on a plan to achieve a certain objective. Here components means actual parts, managerial steps or a subsystem in a multilevel structure. An information system is efficient at providing end users with 3 kinds of information. They are transaction processing system, management reports and decision support system. Transaction processing would be the means by which most data is captured. There are two kinds of transaction, input and output. Management reports fulfill the defined information needs of supervisors. Four types of reports may be produced. They are detailed, historical, summary and exception reports. Each report is constructed from the data that are harnessed and stored during transaction digesting. Decision support system provide end users have real profit obtain needed information when a decision making situation arise. Expert systems are extensions of DSS.

What is Function Overriding?


Function overriding is a technique used to override the particular inherited function. It uses polymorphism. To override an inherited function identical function is redefined in the particular derived class. Now onwards any mention of the function from derived class will not likely call the function that can be defined in base class but it really will call the function defined in derived class only.

What is Function Overloading?


In function overloading, the same function label can be used for assorted implementations. Compiler choose the correct implementation based on style of arguments or based on amount of arguments or based about return type.

What is Abstraction?


Abstraction is the representation of all of the essential features of an item, its possible states and behaviours. The state and behaviour of object in a class are assemble as a single data variety. This data type defines how all objects within a class of objects are to be represented and how they respond.

What is Encapsulation?


Encapsulation is the practice of including in a object everything it requires hidden from other objects from the system. The internal state of an object is not specifically accessible from outside and are not altered by external changes on the application.

What is meant by a protocol in computer communication?


A protocol is a collection of rules that is to become followed by communicating parties to ensure communication takes place with no errors.

How is Assembly Language different from Machine Language ?

Assembly Language use symbols rather than binary codes. It need excellent knowledge of hardware to produce assembly language programs. Machine words use binary codes for representing operations, registers, memory location etc. It is very difficult to post machine language program. Very good expertise in hardware is essential to produce machine language program.

How is an interpreter different from a compiler?

Interpreter translates statement by statement into equipment code and execute immediately. Not any object code is saved. Compiler first translates the source code to object code. This particular object code is executed independently. Every time we want to executed program, interpreter translates the program and hence it is slow-moving. Once object code is available after compilation there' no requirement to translate program hence compilers are fast.

What is a Database? Describe the advantages of a centralized database over separate files for specific applications.

Database is described in following points:

1. It takes less space for storing all data. If data for each application is stored in separate files, key fields must be kept in all the files and there by additional space is consumed. Suppose separate data files are there for promotion of employees are retirement of employees, then the key field employee-id may have to be duplicated in both files. Similarly name of employees also should be duplicated.
2. It is easy to make modification in a single file rather than multiple files. If an employees quits the job, then his details should be removed from all files where ever it occurs. If it is a centralised file then it need to be deleted only from one file.

What is Transaction Processing in industry ? Describe the role of computer network in keeping track of transaction.

Transaction processing systems are systems with large data bases and hundreds of concurrent users that are executing data base transactions. Examples of such systems include systems for reservations, banking, credit card processing, stock market etc. They require high availability and fast response time for hundreds of concurrent users. Computer network is essential to interconnect the hundreds of systems that are involved in transactions. Whenever a transaction is performed, the details of transactions are transferred to all the servers in the network and the data bases in the server must be updated messages are send from the point where transaction takes place to all servers for updating data bases in servers so that data integrity is preserved.

What are Control Lines?

Control Lines are used to receive signals that control various operations memory chip. Basic memory operations are read and write. Control Lines are used to receive read and write signals when read signal is received, the contents of selected memory location is transferred into data lines. When write signal is received, data from data lines is taken into selected memory location.

What are Data Lines?

Data lines are the lines through which data is entered or taken out. If each memory location contain 'm' bits then the number of data lines will be 'm'.

Role of Address lines in the architecture of the RAM of a computer?

Address lines are lines through which address of memory location (from where read or write operator is to be performed) is given. Each memory location has a unique address. If there are n address lines, then the number of memory location is 2n. Address in address lines must be valid until write or read operation is complete.

What is a Line Printer? How can it vary from a Dot Matrix printer?

A Line printer is a manifestation of rapid effect printer in which a line of sort is printed at once. Print velocities of 600 lines to 1200 lines/mt is normal. There are three fundamental sorts of line printers. They are:

1. Drum Printers

2. Chain Printers

3. Bar Printers

A Dot Matrix Printer utilizes a head which hold a lattice of pin heads. Contingent on the character to be printed, a set of pin heads from the network is somewhat anticipated outwards to structure the state of character to be printed. This head gathering moves from one end of sheet to flip side in a line printing one character at once. Head strikes a lace which is kept over the paper and make an impression of the anticipated pins.

What is Optical Mark Reader (OMR) ?

OMR is a special scanning device that can read carefully placed pencil marks on specially designed documents. OMR is frequently used in forms, questionnaires and answer sheets. Modern OMR can read black or blue marks made with ball point pen or fel tip pen as well as pencil, punched and printed marks. Normal scan area includes 12 rows at 0.25 inch centers * 126 mark positions and scanning speed 25 inches per second.

What is Magnetic Ink Character Reader (MICR) ?

MICR is a character recognition technology adopted mainly by the banking industry to facilitate processing of cheques. MICR uses predefined shapes for characters. MICR characters are printed with a magnetic ink or toner. Magnetic printing is used so that the characters can be reliabily read in a system even when they have been overprinted with other marks such as cancellation stamps. MICR reader is similar to audio tape recorder head. The letter forms ensure that each letter produces a unique waveform for the read head. MICR is used by the banks. As the head of MICR reader moves over the characters, according to the character, a unique waveform is generated.

What is data hiding in a program?

Data hiding is a key feature of object oriented programming. It means that data is concealed within a class so that it cannot be accessed mistakenly by functions outside the class. The primary mechanism for hiding data is to put it in a class and make it private. Private data or functions can only be accessed from within the class. Public data or functions are accessible from outside the class. Data hiding provide a mechanism to protect well intenioned programmers from making mistakes.

What are the basic characteristics of a uniprocessor based, multitasking operating system ?

Uniprocessor based multitasking operating system basically works on time sharing basis. Memory of such computers is partitioned and each partition holds a process (program plus associated data). Thus a number of processes stay in memory at the same time. Processor then select one process and execute it for a fixed time (called time slice). If the process is executed completely it is removed and another waiting process is loaded into memory. It the process is not executed completely, then it is suspended temporarily and then processor execute next process for the same time slice. This is repeated for all processes waiting to be executed in memory. Once all the processes are executed in the same manner, the first suspended process is again taken up for execution. This is repeated. This process of executing processes for short intervals is called as multi-programming. A process can be at any time be in running, blocked or ready state.

What is Star Topology ?

In Star Topology all computers are connected to a central computer. All communications between computers are done through the central computer. Central computer almost act like a switching system that connect communicating computers. The main drawback of Star Topology is, in case the central computer fail, then the entire network fails. Moreover since all computers try to communicate through the central computer, it becomes a bottleneck when traffic is high.

What is Ring Topology ?

Here data is transmitted from one computer to another through a ring structure. The computer that wish to send some data sends to its immediate neighbor which forwards to its immediate neighbor and so on. Finally the data passes through the entire ring and reach the sender which removes the data from ring network. It is generally free from collision. It is slow. If a line break then entire network will fail.

What is Bus Topology ?

In Bus Topology, all communication is done through a common medium. It may be a coaxial cable or fiber or twisted pair line. Here all computers can listen to the common line but usually the computer to which the data is addressed only takes the data. Others discard the data. The main drawback of bus topology is data collisions can take place. Two computers can try to use the common physical medium at the same time. Various collision control techniques are adopted practically. As number of computers increase possibility of collision also increase.

Write a single C++ statement that subtracts the sum of x and y from z and then incrementing.

Z-(x+y)+1
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