Computer Science – CE -2013 - Section A

7/29/2019 Computer Science CE -2013 - Section A

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Candidate will be asked to attempt total five questions including onecompulsory objective type question. They will attempt at-least one

question from each section. Each question will carry 20 marks.


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Computer Architecture Operating System

Computer Networks


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Structured and Object OrientedProgramming

Data Structures and Algorithms Software Engineering


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Databases Management Web Programming

Computer Graphics


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An early example of an architectural definition of acomputer was John Von Neumann's 1945 paper

Computer architecture refers to specification of the

relationship between different hardwarecomponents of a computer system.

Computer architecture is concerned with how the

central processing unit (CPU) acts and how itaccesses computer memory Computer architectures include cluster computing

and Non-Uniform Memory Access


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CPU: The brains of the PCs followinstructions at a rate of up to3.2billion/sec!

Hard Drive: Stores files (e.g. yourdocuments and games)Typical PC HD

size: 40-160GB (Slow access: 10msaccess) Memory: Also known as RAM Fast-

access memory used by the computerto complete tasks. (Fast access: a fewnanoseconds)

CPU design is the design engineeringtask of creating a central processingunit (CPU), a component of computerhardware. It is a subfield of electronicsengineering and computerengineering.


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A common misunderstanding of the phrase "reduced instruction setcomputer" is the mistaken idea that instructions are simply eliminated,resulting in a smaller set of instructions.

In fact, over the years, RISC instruction sets have grown in size, andtoday many of them have a larger set of instructions than many CISC

CPUs.[18][19] Some RISC processors such as the PowerPC haveinstruction sets as large as, say, the CISC IBM System/370; andconversely, the DEC PDP-8clearly a CISC CPU because many of itsinstructions involve multiple memory accesseshas only 8 basicinstructions, plus a few extended instructions.

The term "reduced" in that phrase was intended to describe the fact thatthe amount of work any single instruction accomplishes is reducedatmost a single data memory cyclecompared to the "complexinstructions" of CISC CPUs that may require dozens of data memorycycles in order to execute a single instruction.[20] In particular, RISCprocessors typically have separate instructions for I/O and dataprocessing.


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A stored-program computer is one which storesprogram instructions in electronic memory.[1]Often the definition is extended with the

requirement that the treatment of programs anddata in memory be interchangeable or uniform

A computer with a von Neumann architecturestores program data and instruction data in the

same memory; a computer with a Harvardarchitecture has separate memories for storingprogram and data


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In the simplest sense, parallel computing isthe simultaneous use of multiple computeresources to solve a computational problem:

To be run using multiple CPUs A problem is broken into discrete parts that

can be solved concurrently

Each part is further broken down to a seriesof instructions Instructions from each part execute

simultaneously on different CPUs


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SIMD (Single Instruction Multiple Data) In non-parallel system/software data flow in 1

instruction at a time with multiple data chunks

E.g. Arithmetic & Logical operations inprogramming and transfer of data.

MIMD ( Multiple Instruction Multiple Data)

In parallel computing if program architecturesupport : multiple data process at time withmultiple instruction

E.g. 2x5+6/5x3(2+1)


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An operating system (OS) is a collection ofsoftware that manages computer hardware

resources and provides common services forcomputer programs.


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User A user is an agent, either a human agent (end-user) or

software agent, who uses a computer or network

service. A user often has a user account and isidentified by a username (also user name) Application software

Application software, also known as an application oran app, is computer software designed to help the

user to perform specific tasks. Examples includeenterprise software, accounting software, officesuites, graphics software , Browsers and mediaplayers.


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Personal computer hardware

the component devices that are the building

blocks of personal computers. These are typicallyinstalled into a computer case, or attached to it bya cable or through a port


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Process management Interrupts

Memory management File system Device drivers Networking (TCP/IP, UDP) Security (Process/Memory protection) I/O


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Process management an integral part of any modern day operating system

(OS)

The OS must allocate resources to processes, enableprocesses to share and exchange information, protectthe resources of each process from other processesand enable synchronization among processes

To meet these requirements, the OS must maintain a

data structure for each process, which describes thestate and resource ownership of that process, andwhich enables the OS to exert control over eachprocess


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Interrupt an interrupt is a signal to the processor emitted

by hardware or software indicating an event that

needs immediate attention A hardware interrupt is an electronic alerting signal

sent to the processor from an external device, either apart of the computer itself such as a disk controller oran external peripheral.

A software interrupt is caused either by anexceptional condition in the processor itself, or aspecial instruction in the instruction setwhich causesan interrupt when it is executed


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Memory management

Memory management is the act of managing

computer memory. The essential requirement of memory

management is to provide ways to dynamically

allocate portions of memory to programs at their

request, and freeing it for reuse when no longerneeded

This is critical to the computer system.


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File system A file system (or filesystem) is an abstraction to store,

retrieve and update a set of files The term also identifies the data structures specified by

some of those abstractions, which are designed toorganize multiple files as a single stream of bytes, and thenetwork protocols specified by some other of thoseabstractions, which are designed to allow files on a remotemachine to be accessed

By extension, the term also identifies software or firmwarecomponents that implement the abstraction (i.e. thatactually access the data source on behalf of other softwareor firmware that uses those components)


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Device driver

In computing, a device driver or software driver is

a computer program that operates or controls aparticular type of device that is attached to acomputer

A driver typically communicates with the device

through the computer bus or communicationssubsystem to which the hardware connects


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Computer security

Computer security is information security as

applied to computers and networks.


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Input/output In computing, input/output or I/O is the

communication between an information

processing system (such as a computer) and theoutside world, possibly a human or anotherinformation processing system

Inputs are the signals or data received by the

system, and outputs are the signals or data sentfrom it. The term can also be used as part of anaction; to "perform I/O" is to perform an input oroutput operation


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Types of operating systems

Real-time

Multi-user Multi-tasking vs. single-tasking

Distributed

Embedded


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A computer network, or simply a network, is acollection of computers and other hardwareinterconnected by communication channels thatallow sharing of resources and information.

Where at least one process in one device is able tosend/receive data to/from at least one processresiding in a remote device, then the two devices aresaid to be in a network. A network is a group ofdevices connected to each other

Networks may be classified into a wide variety ofcharacteristics, such as the medium used to transportthe data, communications protocol used, scale,topology, benefit, and organizational scope.


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History In September 1940, George Stibitz used a

Teletype machine to send instructions for a

problem set from his Model at Dartmouth Collegeto his Complex Number Calculator in New Yorkand received results back by the same means

Early networks of communicating computers

included the military radar system Semi-Automatic Ground Environment (SAGE), startedin the late 1950s.


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Communication media

Computer networks can be classified according to

the hardware and associated software technologythat is used to interconnect the individual devicesin the network, such as electrical cable

(HomePNA, power line communication, G.hn),

optical fiber, and radio waves (wireless LAN). Inthe OSI model, these are located at levels 1 and 2.


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Communication media (Continue)

Wired technologies

Wireless technologies Exotic technologies


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Communications protocols and networkprogramming

Ethernet IEEE 802

IEEE 802.11

MAC bridging (IEEE 802.1D)


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Communications protocols and networkprogramming(Continue)

Internet Protocol Suite The Internet Protocol Suite, often also called TCP/IP, is

the foundation of all modern internetworking

SONET/SDH

Synchronous optical networking (SONET) andSynchronous Digital Hierarchy (SDH) are standardizedmultiplexing protocols that transfer multiple digital bitstreams over optical fibre using lasers


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Communications protocols and networkprogramming(Continue)

Asynchronous Transfer Mode Asynchronous transfer mode (ATM) is a switching

technique for telecommunication networks. It usesasynchronous time-division multiplexing and encodesdata into small, fixed-sized cells. This differs from otherprotocols such as the Internet Protocol Suite or Ethernetthat use variable sized packets or frames.


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Communications protocols and networkprogramming(Continue) Network programming

Computer network programming involves writingcomputer programs that communicate with each otheracross a computer network

Different programs must be written for the client

process, which initiates the communication, and for theserver process, which waits for the communication to beinitiated. Both endpoints of the communication flow areimplemented as network sockets; hence networkprogramming is basically socket programming.


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Scale

Personal area network

A personal area network (PAN) is a computer networkused for communication among computer and differentinformation technological devices close to one person.Some examples of devices that are used in a PAN arepersonal computers, printers, fax machines, telephones,

PDAs, scanners, and even video game consoles.

A PAN may include wired and wireless devices.


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Scale (Continue) Local area network

A local area network (LAN) is a network that connectscomputers and devices in a limited geographical area such ashome, school, computer laboratory, office building, or closelypositioned group of buildings.

Home area network A home area network (HAN) is a residential LAN which is

used for communication between digital devices typically

deployed in the home, usually a small number of personalcomputers and accessories, such as printers and mobilecomputing devices. An important function is the sharing ofInternet access, often a broadband service through a cable TVor Digital Subscriber Line (DSL) provider


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Scale (Continue)

Metropolitan area network

A Metropolitan Area Network (MAN) is a large computernetwork that spans a metropolitan area or campus. Itsgeographic scope falls between a WAN and LAN. MANsprovide Internet connectivity for LANs in a metropolitanregion, and connect them to wider area networks like

the Internet.


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Scale (Continue)

Wide area network

A Wide Area Network (WAN) is a

network that covers a broad area (i.e.,any telecommunications network thatlinks across metropolitan, regional, ornational boundaries) using private orpublic network transports.


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Organizational scope Intranets and extranets

An intranet is a set of networks, using the Internet Protocoland IP-based tools such as web browsers and file transferapplications, that is under the control of a singleadministrative entity.

An extranet is a network that is limited in scope to a singleorganization or entity and also has limited connections to thenetworks of one or more other usually

Internet The Internet is a global system of interconnected

governmental, academic, corporate, public, and privatecomputer networks. It is based on the networkingtechnologies of the Internet Protocol Suite.


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Network topology Common layouts

A network topology is the layout of the interconnections of thenodes of a computer network. Common layouts are: A bus network: all nodes are connected to a common medium

along this medium. This was the layout used in the originalEthernet, called 10BASE5 and 10BASE2.

A star network: all nodes are connected to a special centralnode. This is the typical layout found in a Wireless LAN, whereeach wireless client connects to the central Wireless access point.

Aring network: each node is connected to its left and rightneighbor node, such that all nodes are connected and that eachnode can reach each other node by traversing nodes left- orrightwards. The Fiber Distributed Data Interface (FDDI) made useof such a topology.

A mesh network: each node is connected to an arbitrary numberof neighbors in such a way that there is at least one traversalfrom any node to any other.

A fully connected network: each node is connected to everyother node in the network.

Overlay network An overlay network is a virtual computer network that is built

on top of another network. (e.g. VPN or Peer to Peer)


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Basic hardware components

Network interface cards

Repeaters and hubs Bridges

Switches

Routers Firewalls


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Network performance

Circuit-switched networks:

Asynchronous Transfer Mode (ATM) network,quality of service (QoS),

Network security Network resilience Views of networks


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OSI model The Open Systems Interconnection (OSI) model (ISO/IEC 7498-

1) is a product of the Open Systems Interconnection effort atthe International Organization for Standardization.

Layer 1: physical layer Layer 2: data link layer

WAN protocol architecture

Layer 3: network layer

Layer 4: transport layer

Layer 5: session layer Layer 6: presentation layer

Layer 7: application layer

Computer Science – CE -2013 - Section A

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