What do you mean by Office Automation?

Office Automation system is an information system that supports the wide range of business office activities that provide for improved work flow between workers. OAS help employees create and share documents that support day to day office activities. OAS system is basically an information system. It consists of computer systems and trained operations and software systems that help in creating and sharing documents. Most office automation systems include data base of employees, activities of organization and information related to those who have direct interaction with the organization. Standard formats of forms, applications etc. are stored in computers and at the chick of a button related information is generated. Usually modern office automation system uses computers connected to networks so that activities of various departments can be co-ordinated. Biometric attendance marking systems, sophisticated I/O devices, storage media to store every activity automatically are also part of modern office automation system.

What is an algorithm and flow-chart?

An algorithm is a detailed sequence of simple steps that are needed to solve a problem.

A flow chart is a graphical representation of an algorithm.

What is a file system and an i-node?

File system is a method of storing and organising computer files and their data. It organises the files into a database for storage, organisation, manipulation and retrieval by the computers operating system.

I-node is a unique data structure that contains information about file. Each file has an associated i-node which is created at the time of creation of file. Each file has an i-node and is identified by an i-node number. I-nodes store information on files such as user, group, ownership access mode and type of file and the pointers to blocks of file etc.

User programs before execution, is brought into memory. Memory is partitioned and each partition contains a base address and a size. Base address is stored in a relocation register before execution of program of program and the size of program checked against the allowable size and addresses that are generated by the program are continuously monitored. This is done with the help of a limit register. If base address plus the address generated by the program exceed the limit register contents, then it result in trap being generated and further execution of the program is not allowed. Operating systems have other protection mechanisms also like access rights bits to implement read/write/execute accesses. Only owners of a file may be allowed to execute. If only owner allow others and group members, they can execute the files. This is done by setting access rights bits by owner of file.

List six major steps that one can take in setting up a database for a particular enterprise?

The six major steps involved in setting up a database for an enterprise:

1. Requirement Analysis
2. Conceptual database design
3. Logical database design
4. Scheme Refinement
5. Physical database design
6. Security design

Explain the difference between the logical and physical data independence?

Data independence is the capacity to change the schema at one level of database system without having to change the schema at the next higher level. Physical data independence refers to the ability to modify the internal schema without having to change the conceptual or external schemas. That is the application programs remain the same even though the schema to physical level gets modified. Modifications at the physical level are occasionally necessary to improve the performance of the system.

Logical data independence refers to the ability to modify the conceptual schema without having to change external schema or applications programs. The logical data independence ensures that the application programs remain the same. Modifications at the conceptual level are necessary whenever logical structures of the database get modified because of some unavoidable reasons.

List four significant differences between a file processing system and a DBMS.

1). The Database Management System allows access to tables at a time. A file management system allows access to single file at a time. File systems accommodate flat files that have no relation to other files.

2). A database coordinates the physical and logical access to the data. A file processing system only coordinates physical access to the data.

3). A DBMS reduces the amount of data duplication. Files often have redundant or duplicate data items.

4). A DBMS is designed to allow flexibility using queries that gives access to the data. A file processing system only allows pre-determined access to data.

5). A DMBS is designed to co-ordinate and permit multiple users to access data at the same time. A file processing system is much more restrictive in simultaneous data access.

What are linkers and loaders?

A loader is a program that places programs into main memory for execution. The assembler or compiler outputs the machine language translation of a program on a secondary storage device. The loader places this machine language into memory. Loader program is much smaller than assembler or compiler. Thus more memory space will be available for user programs because at the time of executing user programs assembler or compiler need not be in memory.

Typical user program consists of a number of modules. A function may be called from another function. Until the modules are the loaded into main memory, the address of various functions cannot be determined. The purpose of linker is to link various modules by placing proper address of functions at their calling point in other functions. After the linker links the modules, they are now ready to execute them.

What is an Interrupt in computer system?

Interrupt is an output to the CPU that causes CPU to suspend its normal sequence of execution and force the CPU to branch to a predetermined memory location and execute program located there. After executing that program CPU return back to the initial program that it was executing and resume its execution. When interrupt occur:

1. CPU completes the current instruction it is executing.

2. Save program counter (PC) contents in a stack.

3. Load PC with the address of interrupt service subroutine.

4. Executes the interrupt service subroutine.

5. Return to the main program and resumes its execution by loading from stack into PC the address which was earlier stored.

Explain the important aspects in which the Windows operating system enhances the MS-DOS operating system.

Windows operating system provide following enhancements to the old MS DOS operating system:

1. GUI capability: Windows is graphical user interface based system and it is user friendly.
2. It provides single user multitasking facility. User can open a number of windows and through each execute different task on time sharing basis.

Windows OS contain a cache manager that improves the performance of file based I/O by causing recently referenced disk data to reside in main memory for quick access and by deferring disk writes by holding the updates in memory for short time before sending them to the disk. Windows security references monitor enforces better security to the computer system than DOS. Windows support threads and symmetric multiprocessing.

What is time-shared operating system and briefly explain it.

In a time sharing operating system, multiple users simultaneously access the system through terminals with the operating system interleaving the execution of each user program in a short bust or quantum of computation. Time sharing system give an impression to each user that the computer is dedicated to him because of the slow nature of human response compared to computer.
The type of events that lead to each state transition for a process and the possible transitions are:-

1. New: A new process is created to execute a program. This happens when user submit a job or an interactive user give a command through terminal.

2. Ready: The OS will move a process from the new state to the Ready state when it is prepared to take on an additional process.

3. Running: When it is time to select a new process to run the OS choose one of the processes in the ready state. This is the job of scheduler.

4. Exit: The currently running process is terminated by the operating system when it has completed or if it aborts. Termination can be due to many reasons other than completion of program execution, like arithmetic error, I/O failure, protection error, bounds violation etc.

5. Ready: When a running process reach its allotted time limit or when the allotted quantum of execution is over it is moved to ready list and remain there in a suspended state until again its allotted time arrive.

An Operating System Is often defined as a resource manager. Explain which resources of a computer it manages and how it manages.

Operating system can be considered as a resource manager. It is software that manages the resources available in a computer system. Operating system can be considered as collection of program modules. Each module has a distinct function, and it accomplish fully or partially the task of managing some computer resources. There are four major resources. Various resources and software that accomplish the task of managing the resource are given below:

Memory management module partition memory into pages and implement concepts like virtual memory, cache memory etc.

Scheduler decides which process is to be scheduled for execution and for how much time in a time sharing system.

Some devices are inherently non-sharable. Operating systems manage these types of devices using a technique called spooling.

One of the most important tasks of an operating system is the effective management of information. The modules of the operating system dealing with the management of information are called the file system. The purpose of file system is to free the programmer from the problems related to the allocation of space for his information, as well as to free from other physical problems such as storage format and I/O accessing. Information is stored files and they are organized in the form of a tree structure where each root/sub root in tree is a special file called directory. They contain information about other files.

How does TCP ensure reliable transfer of packets?

TCP uses acknowledgement mechanism to check safe and sound arrival of data. TCP uses error control which include mechanisms for detecting corrupted segments, lost segments, out of order segments. TCP achieve this using three tools, check sum, acknowledgement and time out. Each segment includes a checksum field which is used to check for a corrupted segment. If the segment is corrupted it is discarded by the destination TCP and is considered as lost. TCP uses a 16 bit checksum that is mandatory in every packet. Check sum is computed at the source machine and attached with packet. Destination machine recomputes the checksum and if the checksum in packet and recomputed checksum are same then the packet is accepted as a valid packet, otherwise it is discarded. TCP uses acknowledgements to confirm the receipt of packets. When a packet is corrupted or lost or delayed, it is re-transmitted. TCP normally maintains a re-transmission time out time (RTO) for all outstanding packets. When the timer runout, the earliest outstanding segment is re-transmitted. The value of RTO is dynamic in TCP and is updated based on the round trip time of packets. RTT is the time needed for a packet to reach destination and for an acknowledgement to be received.

What are the functions of TCP and IP?

TCP/IP is a protocol suite that defines the exchange of transmissions across Internet. It is a 5 layer protocol suite. TCP is the transport layer protocol. It is connection-oriented, reliable transport protocol. TCP allows the sending process to deliver data as a stream of bytes and allows the receiving process to obtain data as a stream of bytes. TCP creates an environment in which the two process seem to be connected by an imaginary tube that carries their data across the Internet. TCP offers full duplex service in which data can flow in both directions at the same time. TCP is a reliable transport protocol. It uses an acknowledgement mechanism to check the safe and sound arrival of data. TCP use flow control. The receiver of the data controls the amount of data that are to be sent by the sender. TCP also provide error control and congestion control.

Internet working Protocol (IP) is the transmission mechanism used by the TCP/IP protocols. It is an unreliable and connection less protocol used by the internet layer in the 5 layer TCP/IP protocol suite. IP transports data in packets called datagrams each of which is transported separately. Datagrams can travel along different routes and can arrived out of sequence or be duplicated. IP does not keep track of the routes and has no facility for reordering datagrams once they arrive at their destination. IP uses four supporting protocols.

ARP: Address Resolution Protocol
RAPP: Reverse Address Resolution Protocol
ICMP: Internet Control Message Protocol
IGMP: Internet Group Message Protocol

ARP is used to associate a logical address with a physical address.

RAPP allows a host to deliver its Internet address when it knows only its physical address.

ICMP is a mechanism used by hosts and gateways to send notification of datagram problems back to sender.

IGMP is used to facilitate the simultaneous transmission of a message to a group of recipients.

What do you understand by scope of a variable ?

Scope of a variable means availability of a variable. The variable can be accessed only within the function where it is declared. Global variables are accessible within all functions. A variable defined within a function is not visible in other functions. If local variable and global variable have same name, then within the function, if the name is used, then the value of local variable is accessed. That is local variable overrides the global variable.

What is Device Driver?

Device drivers are programs which when executed by CPU result in operation of an equipment. For example a printer driver is executed when print command is given. This program when executed result in generation of proper data for printer operation and for initializing printer controller and associated circuits.

What is Protocol? What is IP Protocol?

A Protocol is a set of rules that is to be followed between two communicating parties so that communication between them can take place smoothly.

IP is the standard Internet Protocol. It is the protocol used for communication over Internet.

What is flip-flop?

Flip flop is a one bit memory. It is a circuit that is used to store one bit. Flip flop is the basic building block in sequential circuit. It is used to store the state of sequential circuit so that the next state will be based on the current state of the circuit. They are used in counters, shift registers, sequence generators etc.

What do you understand by booting of a computer? What are the main activities that are carried out by a computer during booting?

Booting in modern PC refers to the initial set of process that PC does when it is powered ON. When power is turned ON, control is transferred automatically to address FFFFO by hardware. This location is in ROM and contains a jump to boot strap procedure in the BIOS ROM. The boot strap procedure carries out some hardware tests and if the machine passes the test, it tries to read the boot sector from diskette A. If no diskette is present in drive A, the primary boot sector of hard disk is read in. The primary table in primary boot sector tells the where the partition are and which one is active. The active partition is read and then executed. The boot sector reads its own root directory to see if io.sys and msdos.sys are present. If so it reads then both into memory and transfers control to io.sys. Once loaded io.sys calls BIOS procedures to initialise the hardware. Then sysinit program is executed and reads config.sys to configure the system.

Why data in an RDBMS needs to be normalized ?

Normalsation is the process of analysing the given relation schemas based on their functional dependency and primary keys to achieve the desirable properties of minimising redundancy and minimising insertion, deletion and update anomalies. Unsatisfactory relation schemas that do not meet certain conditions (called normal form tests) are decomposed into smaller relations that meet the tests and hence possess the desirable property.

Through normalisation we can achieve the following benefits:

1. Minimise redundancy
2. Minimise insertion abnormalities
3. Minimise deletion abnormalities
4. Minimise update abnormalities

Consider a relation which contain employee details and departments. There are certain problems in this type of data base. If we want to insert a new department without employees it can cause difficulties. Normally employee identification number ( or social security number etc.) may be a key value. We cannot keep it null. But if we have separate employee and department tables then such a problem will not raise. New department can be inserted in the department table and new employee will be entered into employee table and they do not interfere with each other.

What are the advantages of storing data pertaining to an application in a database management system compared to storing data in a file?

Storing data in a file system has the following disadvantages:

1. Data Redundancy and Inconsistency: There is a possibility that same data may be stored in several files. Various copies of same data in files may not agree leading to inconsistencies.

2. Difficulty in Accessing Data: It is difficult to access data from file systems. If data is stored in different files and if we want to access them from different places we need to manually access them from different files. Conventional file processing environment do not allow needed data to be retrieved in a convenient and efficient manner.

3. Data Isolation: Since data are scattered in various files and files may be in different formats, it is difficult to write new application programs to retrieve the appropriate data.

4. Atomicity Problem: It is difficult to perform roll back of partial transaction in case of failures in a file system. This leads to automicity problems.

5. Concurrent Access Anomalies: In file systems it is very difficult to implement concurrent access where multiple users are allowed to update the data simultaneously.

6. Security: Not all users must be allowed to access all the information. The users must be allowed to access only the relevant data. It is difficult to implement such things in classical file system.

Database systems are developed to overcome these difficulties. DBMS consist of a collection of interrelated data and a collection of programs to access data. The primary goal of DBMS is to provided an environment that is both convenient and efficient for people to use in retrieving and storing information.

What do you understand by Method Overloading ?

Method overloading is a logical method of calling several functions with arguments and data types that perform basically identical things by the same name. Suppose we want to find average of integers and floating point numbers, we can give same name. Also, we can have function with same name but different number of arguments.

What is the difference between call by reference and call by the value mechanisms?

There are two basic methods to pass arguments in functions. They are:

1. Function arguments passed by value.
2. Function arguments passed by reference.

When arguments are passed by value, the called function creates a new variable of same type as the argument and copies the arguments value in it. The function cannot access the original variable in the calling program. It can access only the copy it created. Passing arguments by value is useful when the function need not modify the original variable in the calling program.

Passing arguments by reference uses a different mechanism. Instead of a value being passed to the function, a reference to the original variable in the calling program is passed. It is the memory address of the variable that is passed. The advantage of passing by reference is that the function can access the actual variables in the calling program. Using this method, more than one value can be passed to the function. For passing objects call by reference is used.

What will be the implication if data members of a class are declared as public members?

Functions outside the class will be able to access and alter the values of public data.

What is Pie Chart?

Packages like MS Excel supports developing charts (Pie, bar etc.) with minimum effort. Charts help to quickly understand the relationships between data and analyzing them. Pie Charts are good when we are showing the relative portion of numbers that add up to a total. They are good for a single series of data. They are not good when there are too many small size data. They are useful for a single series of data. Pie charts are not good for quantitative displays. In such cases bar charts are suitable. Bar charts can also be used for comparing two set of proportions.

1. In excel the procedure to create pie chart is as follows:
(a) Highlight the data we want to display (i.e., select the data)
(b) From menu bar click on insert.
(c) From the drop down list click chart.
(d) Click on pie in the chart types list under chart sub type click pie of pie.

What is the Importance of graphics?

A picture is worth a thousand words. With graphics it is easy to develop attractive graphs, illustrations and drawings. They can be used to develop advertising borchures, announcements and full colour presentations and to organise and edit photographic images.

What is Continue Keyword in C?

The Continue statement is used to bypass the remainder of the current pass through a loop. The loop does not terminate when a continue statement is encountered. Instead the remaining loop statements are skipped and the computation proceeds directly to the next pass through the loop.

What is Static Keyword in C?

If a data item in a class is declared static, only one such item is created for entire class, no matter how many objects there are. A static data item is useful when all objects of the same class must share a common item of information. Static declaration applied to an external variable or function limits the scope of that object to the rest of the source file being compiled. Internal static variables are local to a particular function, but they remain in existence rather than coming and going each time the function is activated. Thus internal static variables provide private, permanent storage within a single function.

What is Auto Keyword in C?

Auto keyword specify that the variable can be used only within the function. All local variables are by default belong to auto category.

What is Short Keyword in C?

Short keyword is used to declare a variable is of type short. This type of variables occupy two bytes of memory giving it a range of -32768 to 32767.

MS-DOS is an example of a virtual memory operating system?

No, DOS does not support virtual memory UNIX support virtual memory.

Application programs are easier to write compared to system programs?

Yes, to write an application program hardware knowledge is not essential. To write system software hardware knowledge is essential.

A management information system is an example of a system program?

No, MIS is an application software. System software helps users use the computer in a friendly manner. They include compiler, assembler, linker, loader, operating system etc.

The secondary memory of a computer is also known as Volatile memory?

No, Volatile memory refers to the memory whose contents are lost upon power off condition. Secondary memories are permanent storage devices and does not lose data when power is off.

A variable defined within a function is visible to all functions onwards from its point of definition?

No, a variable defined within a function is visible only within the function (local variable). If a variable is to be visible for all functions, it must be defined in the top of the programs.

A variable of type char can be used to store the integer 101?

Yes, In a variable of type char upto 256 can be stored as 1 byte memory space is allocated for char type variable.

Difference Between System Software and an Application Software?

System Software is any computer software that manages and controls computer hardware as well as which makes users use the computer in a friendly manner. They include Compilers, Assemblers, Operating System etc.

Application Software are programs that enable the end user to perform specific, productive tasks. Some examples are Airline reservation software, banking software, word processing software etc.

The primary memory of every computer is essentially magnetic memory?

No, Primary memory of modern computers are essentially semiconductor memories.

L1 cache is a split memory to speed up execution?

Yes, L1 cache works based on principle of locality of reference and is used for increasing speed of execution.

Modem as well as Ethernet Card are essential to provide Data One Broadband Connection?

Yes, modem and ethernet are required to translate signals from computer to a form that is acceptable by broadband connection and vice-versa.

C++ compiler cannot handle scanf and printf commands as available in C?

No, by including stadio.h header file we can handle scanf and printf commands available in C.

Microsoft windows 2000 is a single user operating system.

Yes, only one user can login and work with windows 2000 OS. Multiple windows can be opened and multiple programs can be executed on time sharing basis.

Pentium is a 64 bit machine since it has got 64 bit Data Bus?

Yes, It has 64 bit data bus and internal processing capability.

What are the different forms of secondary storage media employed in modern day computer systems?

Various secondary storage devices are classified into two categories
1. Detachable storage devices
2. Fixed storage devices

Detachable storage devices can be easily removed and can be inserted latter when needed. Some examples of detachable storage devices are Floppy disk, CD, DVD etc. Floppy disk is magnetic storage device where data is stored in concentric tracks of magnetic material in a plastic disk. They are used to store small amount of data (upto 1.44 MB). They can be easily inserted and can be easily removed.
Another storage device in CD (Compact Disk) and DVD (Digital Video Disk). They can be used to store large volume of data. A typical CD can store 700 Megabyte data and a DVD can store 8 Giga bytes to 16 Giga Byte data. They are used to store audio and video data as well as general data. Tapes are also detachable storage devices. They are basically sequential storage devices. They can be used for storing backup data and for on-line recording of transactions for future reference or for transaction processing system. They have magnetic based read/write mechanism.
One of the most popular secondary storage device is hard disk. Hard disk contains a stack of platters in which data is stored in concentric circular tracks. They are used in almost every computer. They are used to store the operating systems and files that are frequently used. Hard disks are not generally removed from computer. Currently small hard disks of 160 Giga bytes that can be externally connected through USB ports are available.
Another secondary memory device that is gaining popularity is pen drives. They are basically EPROM (Erasable and Programmable Read Only Memory) based memory. They are also called flash memory. They can be connected through the USB port of computer and can store upto 8 GB of data. They can be easily detached and carried in pocket. They can be used to store any type of data.

What is Physical Layer?

The physical layer is responsible for encoding and transmission of data over network communications media. It operates with data in the form of bits that are sent from the physical layer of the sending (source) device and received at the physical layer of the destination device. Ethernet, Token Ring, SCSI, hubs, repeaters, cables and connectors are standard network devices that function at the physical layer. The physical layer is also considered the domain of many hardware related network design issues such as LAN, WAN topologies and wireless technology.
Normally the application programmers and users use layer 5 protocols (application layer. Layer 3 and 4 protocols are services provided by the TCP/IP stack in operating system. Microcontroller firmware in the network adapter handles layer 2 issues. It is supported by driver software in the operating system. Non-programmable analog and digital electronics are normally in charge of the physical layer typically using an application specific integrated circuit (ASIC) chipset for each radio interface or other physical standards.

What is Data Link Layer?

Data Link Layer is used to move packets from the network layer on two different hosts. The process of transmitting packets on a given link layer and receiving packets from a given layer can be controlled both in the software device driver for the network card as well as on firmware or specialist chip sets. These will perform data link functions such as adding a packet header to prepare it for transmission, and then actually transmit the frame over a physical medium. For Internet access over a dial up model, IP packets are usually transmitted using PPP (Point to Point Protocol). For broadband Internet access such ADSL or cable modem PPPoE is used. On a local wired network, Ethernet is usually used and on wireless network IEEE 802.11 is usually used. For wide area network either PPP over T-Carrier or E-Carrier lines, Frames relay, ATM or packet over SONET/SDH (POS) is often used. The link layer can also be the layer where packets are intercepted to be sent over a virtual private network. When this is done, the link layer data is considered the application data and proceeds back down the IP stack for actual transmission. On the receiving end, the data goes up the IP stack twice, once for routing and the second time for the VPN (Virtual Private Network).

What is Network Layer?

It gets the packets across networks. It transfers data from a source network to destination network. This generally involves routing the packet across a network of networks. In Internet protocol suite, IP (Internet Protocol) performs the basic task of getting packets from source to destination. IP can carry data for a number of different upper layer protocols. These protocols are each identified by a unique protocol number. ICMP and IGMP are protocols 1 and 2 respectively. ICMP (Internet Control Message Protocol) is used to transmit diagnostic information about IP. IGMP (Internet Group Message Protocol) is used to manage IP multicast data. These protocols perform internetwork layer functions. All routing protocols like OSPF and RIP are also part of network layer.

What is Transport Layer?

Transport Layers responsibilities include end to end message transfer capabilities independent of the underlying network along with error control, fragmentation and flow control. End to end message transmission or connecting applications at the transport layer can be categorized as either.
1. Connection oriented (Ex: TCP)
2. Connection less (Ex: UDP)
The transport layer can be thought of literally as a transport mechanism whose responsibility is to make sure that its contents reach its destination safely and soundly unless a higher or lower layer is responsible for safe delivery. The transport layer provides this service of connecting applications together through use of ports.
TCP is connection oriented protocol that addresses numerous reliability issues to provide a reliable byte stream. TCP features are:
1. Data arrives in order
2. Data has minimal error
3. Duplicate data is discarded
4. Lost packets are resent
5. Includes traffic congestion control.
The new transport layer protocol SCTP is a reliable connection oriented, message-stream oriented transport mechanism. It provides multiple streams multiplexed over a single connection. It also provides multi-homing support, in which a connection end can be represented by multiple IP addresses. Such that if one fails, the connection is not interrupted.
UDP is a connection-less data-gram protocol. It is a best effort protocol. Reliability is addressed through error detection using a weak checksum algorithm. It is used for applications such as streaming media (audio, video, VOIP etc.) In these applications timely arrival of data is more important than reliability.
The appropriate transport protocol (TCP, UDP, and SCTP) is chosen based on the higher layer protocol application. For example FTP (file transfer protocol) expects a reliable transfer whereas Network File System assumes non reliable data transfer. Applications like VOIP can tolerate some loss of packets but not reordering or delay that could be caused by re-transmission.

What is Application Layer?

The Application Layer is used by most programs for network communication. Data is passed from the program in an application specific format, then encapsulated into a transport layer protocol. Internet Protocol stack has no layers between application and transport layers. The application layer must include any protocols that act like OSI reference models presentation and session layer protocols. This is done through libraries. Data sent over the network is passed into the application layer where it is encapsulated using the application layer protocol. From there the data is passed down to the lower layer protocol of the transport layer. Two most common end-to-end protocols are TCP and UDP. Common servers have specific ports assigned to them (HTTP has port 80 and Telnet has port 23 etc.) While clients use ephemeral ports. Some protocols such as file transfer protocol (FTP) and Telnet may set up a session using a well known port but then redirect the actual user session to ephemeral ports. Routers and switches do not utilize generally this layer, but some protocols like resource reservation protocol do use application layer.

What is the structure of a typical UNIX file system?

UNIX file system structure is shaped like an upside down tree. Directories enables us to keep related files in one place, where we see them only when we want. Directories can be subdivided into sub-directories and so on. All these comes under a root directory called root. Under the root there are standard directories called administrative directories. Some of the standard administrative directories are bin, dev etc, lib etc.

How does a Floppy Disk work?

A Floppy Disk is a plastic disk coated with magnetic material. Data is stored in the disc in concentric circles called tracks. Each track consists of tiny magnetic spots whose orientation desides whether a ‘1’ or a ‘0’ is stored in that spot. This disc is enclosed in a hard rectangular jacket. There is flat circular metallic connector at center of the disc and a window on the hard jacket-through which the floppy disk can be viewed. This window is usually covered by a metallic covering that is sliding type and fixed on the hard jacket. When floppy is inserted in the floppy disk drive, a spindle goes into the circular connector and make the floppy rotate. The metallic covering over the window is slided and head is positioned over the disc through this window and read/write operations are performed. Commonly available floppy disks are of high density type and they can store upto 1.44 MB data.

What is a file? What are the features of file management?

File is an organised collection of related records. File management is one of the tasks of the operating system. File management is concerned with the logical organisation of information, its security and manipulation. Information is grouped as files and files are grouped under various directories. Files are the leaf nodes of a hierarchial tree structure. Directories are subdivided into sub-directories. File management also includes security features like access rights (read, write, execute and a combination of them). File management also include the physical organisation of files and managing the file structures. File structure can be sequential, indexed, index-sequential etc.

Flash memory is a writable non-volatile memory?

Yes, Flash memories use EEPROM Data can be written and erased as many times as we wish. EEPROM are nonvolatile. Data is not lost when power is turned off.

A-23 is a valid C++ constant?

No, A-23 is not a valid constant. It contain a variable 'A'.

If is a valid C++ identifier?

Yes, If is a valid identifier but 'if' is not a valid identifier. 'If' is a reserve word.

TCP/IP is actually two protocols rolled into one?

Yes, it contains two protocols one is transmission protocol that deals with transportation of packets from source to destination (TCP). Other protocol is IP (Internet Protocol) which is specifically for transporting data through Internet.

When one needs to connect all the computers in one building, then it is preferable to use a LAN?

Yes, LAN is specifically designed to handle data transfer between computers which are geographically near (within usually 1 km radius). They transfer data through physical medium at high data rates and low error rates. Thus it is most suitable for connecting computers in a building.

Operating System acts as a resource manager for any computer system?

Yes, the function of operating system is to manage the resources (memory, processors, I/O systems, information etc.)

A C++ compiler actually translates a C++ source code into the equivalent machine code of the target CPU?

Yes, like any Compiler C++ compiler translates C++ source code into machine code of the target CPU.

C is a procedural programming language?

Yes, C uses procedures (functions and blocks) to implement code. Each procedure indicate steps that is to be followed to solve a given problem.

Unix is a multiuser operating system?

Yes, through multi-programming feature, multiple users can work on a UNIX machine at same time.

Pentium is a 32 bit machine because it has got a 32 bit Address Bar.

No. Pentium is a 32 bit machine indicate the number of data lines and internal register size are 32 bits. It can do operations (addition, subtraction etc.) on 32 bit operands.

What is Virtual Memory? What are the necessary layers of memory hierarchy that helps to create the virtual memory?

Virtual Memory is a memory management technique in which the computer user is given feeling that unlimited memory is available at his disposal for running programs. Here very large programs are run using small size physical memory. Large programs in secondary memory are divided into fixed size pages and available physical memory is divided into blocks. Block size and physical memory size is kept same. Few pages of program are loaded into the blocks and are executed. When new pages are required for execution they are loaded from secondary memory into one of the blocks replacing the earlier page stored in that block. Using this technique very large programs are executed using small size primary memories. To create virtual memory, two layers of memory is required. One is secondary memory to store large programs/data that is to be executed. Second layer is physical memory to store various pages that is needed currently for execention.

In segmented paged allocation, segmentation is used to facilitate sharing and protection. Paging is used to resolve the fragmentation and recomputing problems and demand paging eliminate the restriction on address space size. A segment table is used along with page tables. One page table is used for each segment and each segment have a corresponding segment page table entry. Using this segment table entry a page table is selected and various entries in that page table corresponds to various pages of that segment.

What are different passes of a compiler?

Various Passes of a Compiler are:

1. Lexial Analysis: This pass recognize the basic elements and creation of uniform symbols.

2. Syntax Analysis: This pass recognize the basic syntactic constructs through reductions.

3. Interpretation: This pass define exact remaining, creation of matrix and tables by action routines.

4. Machine Independent Optimisation: This pass creates a more optimal matrix.

5. Storage Assignment: This pass modifies the identifier and literal tables. It makes entries in the matrix that allow code generation to create code that allocates dynamic storage and that also allow the assembly phase to reserve the proper amount of static storage.

6. Assembly and Output: This pass resolves symbolic addresses and generate machine languages.

What is Formatting?

Formatting is the process of preparing a disk for write operation.

What is Windows 2000?

It is a single user operating system from Microsoft Corporation.

What is Tally 7.2?

Tally is an accounting application software.

What is Cache Memory?

A high speed memory that is placed between processor and main memory which work on the principle of locality of references.

What is NOR?

NOR is a digital gate whose output goes high only when all inputs are low.

What is Function Subprogram?

Function Subprogram is a group of statements which is evoked by other programs through its name. It is usually returns a single value.

What is FTP?

File Transfer Protocol is a protocol used for transfer file from one computer to another through network.

What is Desktop Printer?

Small high quality printers whose usage is user friendly is called Desktop Printer.

What is CRT (Cathode Ray Tube)?

Cathode Ray Tube is an output device used for display of data.

What is Cross Talk?

When two wires are closed and they run in parallel due to electromagnetic induction, data of one line is induced in other one. This is called Cross Talk.

What is Cross Compiler?

Cross Compiler is a Compiler that runs on one machine but translating programs written for another machine.

What is Short Integer?

Short Integer is a declaration that the variable named will have range between -128 to +127 only.

What is Attach?

Attaching is the process of mounting I/O devices in UNIX operating system.

What is ATM?

Asynchronous Transfer Mode is a network protocol in which data transfer rate is very high.

What is FAQ?

Frequently Asked Questions is the text material supplied by the manufacturers regarding the common doubts and their answers.

What is the Full Form of FORTRAN ?

It is a high level language that is suitable for scientific and engineering applications. It is useful where there are lot of equations to be solved.

What is Accumulator Register ?

Accumulator Register is a special register inside CPU in which one of the operand is to be placed before any arithmetic or logic information. Result after the operation is placed in accumulator by CPU.

What is Relational Algebra ?

Relational Algebra is a procedural querry language. It consists of a set of operations that take one or two relations as input and produce a new relation as their result.

What is a Simple Data Type ?

Simple data types are those data types that are directly implemented at processor level.

Eg: Integer, real number, character and pointers.

What is Access Time of a Disk ?

Access time of a disk is the time needed to read a fixed amount of information. It is the sum of rotational latency tr, and seek time ts and data transfer time tt.

i.e. ta=tr+ts+tt

What is Mesh Topology ?

Mesh Topology : This topology is suitable for sub nets. Here each node in network may be connnected to one or more nodes in the network.

If each node is connected to all other nodes in the network, then it becomes a completely connected mesh. Number of links need for each mesh network is large and not suitable for large network.
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