UNIT1-pscp

7/23/2019 UNIT1-pscp

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Unit-1

What is a Computer?

Computer is an electronic device that manipulates information or data. It has the ability to stor

retrieve and process the data. You can use a computer to type documents, send email, and surf th

Internet. You can also use it to handle spreadsheets, accounting, database managemenpresentations, games and more.

A computer is composed of hardware and software, and can exist in a variety of sies an

configurations

!he term hardware refers to the physical components of your computer such as the system unit, mouse

"eyboard, monitor etc.

!he software is the set of instructions that ma"e the computer wor". #oftware is held either on you

computer$s hard dis", C%&'(), %*% or on a dis"ette +floppy dis" and is loaded +i.e. copied fromthe dis" into the computers 'A) +'andom Access )emory, as and when re-uired.

1. With a neat schematic block diagram of a digital computer describe its functional units.

Input Unit:-

Input unit is used to input some sort of data into the computer. Computers accept coded informatio

through input units, which read data. It converts the data into a suitable form that can be understooby the Computer.

!he converted data is stored in the form of $s and /$s and then sent to Central processing unit

!he user can also interact with other devices such as C01, )1 and output unit

Examples:

A "eyboard is an input devicethat inputs characters.

)any other "inds of input devices are available, including 2oystic"s, trac"balls, and mouse, whic

can be used as pointing device. !ouch screens are often used as graphic input devices in con2unction with displays.


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)icrophones can be used to capture audio input which is then sampled and converted into digita

codes for storage and. processing. Cameras and scanners are used as to get digital images.

Output unit:-

Its main function is to send processed results to the outside world that is used to display th

processed results. Accepts the result or data from memory which are in the form of $s and /$s.

(utput the results or data to a form which is suitable for human understanding.

Examples :

*ideo terminals and graphic displays.

!he most familiar example of such a device is a printer. 0rinters employ mechanical impact heads

in"&2et streams, or photocopying techni-ues, as in laser printers, to perform the printing. )onitors, #pea"ers, 3eadphones and pro2ectors are also some of the output devices.

#torage devices such as hard dis", floppy dis", flash drives are also used for input as well as output

Central Processing Unit;-

!he central processing unit +CPU of a computer is a hardware device that executes all th

instructions of a computerprogram. It performs basic arithmetical, logical, and input4output operations of a computersystem.

!his is the unit through which the computer processes all the data accepted through the input unit.

It consists of two functional units5 1. Arithmetic and Logic Unit (ALU)

2. Control Unit (CU)

1. Arithmetic and Logic Unit (ALU);-

o An A61 consists of electronic circuitry which performs calculations with basic arithmet

operations such as addition +7, subtraction +&, multiplication +8, division +4.

o It also consists of logic circuitry which performs logic operations li"e true or false, yes or no.. Control Unit (CU):-

o !he control unitis a component of a computer9s central processing unit +C01 which directs

operation of the processor.o It controls communication and co&ordination between input4output devices.

o It reads and interprets instructions and determines the se-uence for processing the data.

o It performs the tas"s of fetching, decoding, managing execution and, finally, storing results

o !he control unit is the circuitry that controls the flow of data through the processor, and coordinate

the activities of the other units within it.

emor! Unit "U#:-

!he !erm Computer )emory is defined as one or more sets of chips that store %ata4programinstructions, either temporarily or permanently.

!wo types of memory units5

/. 0rimary )emory or )ain )emory:. #econdary )emory

1. !ain !emor" # Primar" !emor" unit:

$A!($andom Access !emor")


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'A) or 'andom Access )emory is the central storage unit in a computer system. It is the place in

computer where the operating system, application programs and the data in current use are "ept temporarilso that they can be accessed by the computer$s processor. !he more 'A) a computer has, the more data

computer can manipulate.

'andom access memory, also called the 'ead4Write memory, is the temporary memory of computer. It is said to be ;volatile$ since its contents are accessible only as long as the computer is on. !h

contents of 'A) are cleared once the computer is turned off.

$%!($ead-onl" !emor")

'() or 'ead (nly )emory is a special type of memory which can only be read and contents of which arnot lost even when the computer is switched off. It typically contains manufacturer$s instructions. Amon

other things, '() also stores an initial program called the ;bootstrap loader$ whose function is to start th

computer software operating, once the power is turned on.

'ead&only memories can be manufacturer&programmed or user&programmed. While manufacturer

programmed '()s have data burnt into the circuitry, user&programmed '()s can have the user load anthen store read&only programs. 0'() or 0rogrammable '() is the name given to such '()s.

Information once stored on the '() or 0'() chip cannot be altered. 3owever, another type o

memory called


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It is the permanent memory which stores large amount of data and instructions permanently.

It$s also called bac" up memory or auxiliary memory.

It is connected to C01 and is made of magnetic material. It is much cheaper than the main storage.

#econdary memory is a non volatile memory.

Non volatile memory5 !he memory that retains its contents permanently even after the computer i

turned off. !hey hold the data permanently.


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!emor":Is used to hold programs and data during execution.

$A!: Primar" memor" is often called as 'A) +'andom Access )emory. It holds all the programs andata the processor is using at a given time. 'A) is volatile because its contents are erased when power i

switched off.

$%!5 !he other type of system memory is '() +'ead only )emory which is permanent because icontents are not erased even when power is switched off. It is usually used to load an operating system.

ard dis :

A hard dis dri/e+&&is a data storage device used for storing and retrieving digital data

information using rapidly rotating dis"s+platter coated with magnetic material. An 3%% retains its data eve

when powered off. %ata is read in a random&accessmanner, meaning individualbloc"sof data can be storedor retrieved in any order rather than se-uentially. An 3%% consists of one or more rigid +BhardB rapidly

rotating dis"s +platters with magnetic headsarranged on a movingactuator arm to read and write data to th

surfaces.

C&-$%! :

C%&'() stands for compact dis" read only memory. It consists of small dis"s similar to thgramophone records to hold digital information. As the name applies they are read only medium. With th

advancement in technology writable C%$s are also available.

0e"oard:

!he "eyboard is the main input device for most computers. It is used to input text or enter commands intthe 0C. >owadays "eyboards with additional features are available li"e multimedia "eyboard, wireles

"eyboard.

!ouse:

With the invention of graphical user interface mouse is used to input information into the computer. 1ser

simply point and clic" to enter information. !he main advantage of mouse over "eyboard is simplicity. Anthere are many operations that are much easier to perform with a mouse then a "eyboard.

!onitor:

!he monitor is the specialied high&resolution screen similar to a television. !he video card sends th

contents of its video memory to the monitor at a rate of or more time per second. !he actual displascreen is made up of red, green and blue dots that are illuminated by electron beam from behind. !he vide

card %AC chip controls the movement of the electron beam, which then controls what dots are turned on anhow bright they are, which then determines the picture you see on the screen.

Poer suppl":

,!P,+#witch )ode 0ower #upply5 !he power supply supplies power to every single part in the 0C. !hmain function of the power supply is to convert the :D * AC into D.D *, E * and /: * %C power that the

system re-uires for the operations.

In addition to supplying power to run the system, the power supply also ensures that the system does not ru

unless the power supplied is sufficient to operate the system properly. !he power supply completes interna
http://en.wikipedia.org/wiki/Non-volatile_memoryhttp://en.wikipedia.org/wiki/Random-accesshttp://en.wikipedia.org/wiki/Block_(data_storage)http://en.wikipedia.org/wiki/Sequential_accesshttp://en.wikipedia.org/wiki/Hard_disk_platterhttp://en.wikipedia.org/wiki/Disk_read-and-write_headhttp://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Non-volatile_memoryhttp://en.wikipedia.org/wiki/Random-accesshttp://en.wikipedia.org/wiki/Block_(data_storage)http://en.wikipedia.org/wiki/Sequential_accesshttp://en.wikipedia.org/wiki/Hard_disk_platterhttp://en.wikipedia.org/wiki/Disk_read-and-write_headhttp://en.wikipedia.org/wiki/Actuator


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chec"s and tests before allowing the system to start. If the tests are successful, the power supply sends

special signal to the motherboard called Poer23ood.

If this signal is not present continuously, the computer does not run. !herefore, when the AC voltage dip

and the power supply becomes stressed or overheated, the Poer23ood signal goes down and forces

system reset or complete shutdown.

4+%,:

I(# stands for asic input and (utput system. 4+%,is a chip located on all motherboards thcontain instructions and setup for how your system should boot and how it operates.

5he 'our main 'unctions o' 4+%,

P%,5 - !est the computer hardwareand ma"e sure no errors exist before loading the operating

system.

4ootstrap Loader: ABoot loaderis the first program +stored in '() which executes +before the

main program whenever a system is initialied. It is usedto bootstrap a computer. !he term bootis used todescribe the process ta"en by the computer when turned on that loads the operating system and prepares the

system for use.

4+%, dri/ers - 6ow level drivers that give the computer basic operational control over yourcomputer9s hardware.

4+%, or C!%, ,etup - Configuration program that allows you to configure hardware settings

including system settings such as computer passwords, time, and date.

C!%, atter":

C)(# +complementary metal&oxide&semiconductor is the term usually used to describe the smallamount of memory on a computer motherboardthat stores the I(#settings.

It stores information such as the system time and date and the system hardware settings for your

computer. !he standard lifetime of a C)(# battery is around / Years.

Peripheral &e/ices:

Any external device, which is not necessary to perform the basic operation of computer, is called a

peripherals. !hey provide additional computing capabilities. =or ex5 0rinters, )odems, and #pea"ers etc.

!odem:

)odem +)odulator and %emodulator is typically used to send digital data over a phone line. !h

sending modem converts digital data into analog data, which can be transmitted over telephone lines, and threceiving modem converts the analog data bac" into digital form. !his is used to connect to Internet.
http://www.computerhope.com/jargon/m/mothboar.htmhttp://www.computerhope.com/jargon/h/hardware.htmhttp://www.computerhope.com/jargon/h/hardware.htmhttp://pcsupport.about.com/od/componentprofiles/p/p_mobo.htmhttp://pcsupport.about.com/od/termsb/p/bios.htmhttp://www.computerhope.com/jargon/m/mothboar.htmhttp://www.computerhope.com/jargon/h/hardware.htmhttp://pcsupport.about.com/od/componentprofiles/p/p_mobo.htmhttp://pcsupport.about.com/od/termsb/p/bios.htm


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Printers

It is a device that must be connected to a computer which allows a user to print items onpaper,such a

letters and pictures.

It can also wor" with digital cameras to print directly without the use of a computer.%ifferent types of printers are / 6aser : In"2et D %ot&)atrix.

6. Computer 7etors:

8hat is 7etor9

A networ" consists of two or more computers that are lin"ed +connected together in order to shar

resources +such as printers and C%s, exchange files, or allow electronic communications.

!he computers on a networ" may be lin"ed through cables, telephone lines, radio waves, #atelliteor infrared light beams.

6.1 7etor 5opologies:

7etor topolog"is the arrangement of the various elements +lin"s, nodes, etc. of a computer netor.!hey describe the physical and logical arrangement of the networ" nodes. +!he way devices on the networ"are physically connected is "nown as the topology.

!he physical topology of a networ" refers to the configuration of cables, computers, and othe

peripherals

&i''erent 5"pes o' 5opologies:

us !opology

#tar !opology

'ing !opology

)esh !opology

!ree !opology

3ybrid !opology

4us 5opolog":

us !opology is the simplest ofnetwor" topologies. In this type of topology, all the nodes +computers as

well as servers are connected to the single cable +called bus, by the help of interface connectors. !his

central cable is the bac"bone of the networ" and is "nown as us +thus the name.


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A terminator is added at ends of the central cable, to prevent bouncing of signals. A barrel connector can be

used to extend it. elow I have given a basic diagram of a bus topology and then have discussed advantages

and disadvantages of us >etwor" !opology

us topologies use coaxial cable.

&d'antages of (us )opolog!:

/. It is easy to set&up and extend bus networ".:. Cable length re-uired for this topology is the least compared to other networ"s.

D. us topology costs very less.

F. 6inear us networ" is mostly used in small networ"s. @ood for 6A>.

*isad'antages of (us )opolog!

/. !here is a limit on central cable length and number of nodes that can be connected.

:. %ependency on central cable in this topology has its disadvantages. If the main cable +i.e. bus encounters some problem, whole networ" brea"s down.

D. us networ"s are important to pay careful attention to termination.


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!o"en contains a piece of information which along with data is sent by the source computer. !his to"e

then passes to next node, which chec"s if the signal is intended to it. If yes, it receives it and passes th

empty to"en into the networ", otherwise passes to"en along with the data to next node. !his procescontinues until the signal reaches its intended destination.

!he nodes with to"en are the ones only allowed to send data. (ther nodes have to wait for an empt

to"en to reach them. !his networ" is usually found in offices, schools and small buildings.

&d'antage of +ing )opolog!J

!his type of networ" topologyis very organied.


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&d'antages of %tar )opolog!

J


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J All the computers have access to the larger and their immediate networ"s.

*isad'antages of a )ree )opolog!

J (verall length of each segment is limited by the type of cabling used.

J If the bac"bone line brea"s, the entire segment goes down.

J )ore difficult to configure and wire than other topologies.

!esh 5opolog":

J In this topology, each node is connected to every other node in the networ".J Implementing the mesh topology is expensive and difficult.

J In this type of networ", each node may send message to destination through multiple paths.

J While the data is travelling on the )esh >etwor" it is automatically configured to reach the destination bta"ing the shortest route which means the least number of hops.

&d'antage of esh )opolog!

J >o traffic problem as there are dedicated lin"s.J It has multiple lin"s, so if one route is bloc"ed then other routes can be used for data communication.

J 0oints to point lin"s ma"e fault identification easy.

*isad'antage of esh )opolog!

J !here is mesh of wiring which can be difficult to manage.

J Installation is complex as each node is connected to every node.J Cabling cost is high

"rid 5opolog":

A combination of any two or more networ" topologies. A hybrid topology always occurs when two different basic networ" topologies are connected.

It is a mixture of above mentioned topologies. 1sually, a central computer is attached with sub

controllers which in turn participate in a variety of topologies


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&d'antages of a ,!brid )opolog!

J It is extremely flexible.

J It is very reliable.

*isad'antages of a ,!brid )opolog!

J etwor" +6A>

)etropolitan Area >etwor" +)A>

Wide Area >etwor" +WA>

0ersonal Area >etwor" +0A>

Local Area 7etor (LA7)

A LAN is a netor! that is used "or communicating among computer devices# usually ithin an o""ic

building or home.

6A>$s enable the sharing of resources such as files or hardware devices that may be needed b

multiple users.

Is limited in sie, typically spanning a few hundred meters, and not more than a mile.

Is fast, with speeds from / )bps to / @bps.

'e-uires little wiring, typically a single cable connecting to each device.

3as lower cost compared to )A>$s or WA>$s

6A>$s can be either wired or wireless. !wisted pair, coaxial or fibre optic cable can be used in wire

6A>$s.

uses a protocol K a set of rules that governs how pac"ets are configured and transmitted.

>odes in a 6A> are lin"ed together with a certain topology.

!hese topologies include5


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us

'ing

#tar 6A>s are capable of very high transmission rates +/s )b4s to @ b4s.

Ad/antages o' LA7

Wor"stations can share peripheral devices li"e printers. !his is cheaper than buying a printer for

every wor"station.

1ser can save their wor" centrally on the networ"$s file server. !his means that they can retrieve thei

wor" from any wor"station on the networ". !hey don$t need to go bac" to the same wor"station all the time.

1sers can communicate with each other and transfer data between wor"stations very easily.

(ne copy of each application pac"age such as a word processor, spreadsheet etc. can be loaded onto

the file and shared by all users.

When a new version comes out, it only has to be loaded onto the server instead of onto every

wor"station.

&isad/antages o' LA7

#pecial security measures are needed to stop users from using programs and data that they should

not have access toL >etwor"s are difficult to set up and need to be maintained by s"illed technicians.

If the file server develops a serious fault, all the users are affected, rather than 2ust one user in the

case of a stand&alone machine.

!etropolitan Area 7etor (!A7):

A metropolitan area netor +!A7 is a large computer networ" that usually spans a city or

large campus.

A )A> is optimied for a larger geographical area than a 6A>, ranging from several bloc"s o

buildings to entire cities.

A )A> might be owned and operated by a single organiation, but it usually will be used by many

individuals and organiations.

A )A> often acts as a high speed networ" to allow sharing of regional resources.

A )A> typically covers an area of between E and E "m diameter.


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5 !elephone company networ" that provides a high speed %#6 to customers an

cable !* networ".

Ad/antages o' !A7s

!he biggest advantage of )A>s is the bandwidth +potential speed of the connecting lin"s. !his means that

resources +such as databases and files shared on the networ" can be accessed extremely -uic"ly.

&isad/antages o' !A7s

!he "ey disadvantage of )A>s is the cost of the cutting&edge technology employed. Also, this e-uipment

generally has to be installed for the first time, as the copper traditionally used for the phone networ" isgenerally considered to be too slow to be annexed for this purpose.

8ide Area 7etor (8A7):

WA> covers a large geographic area such as country, continent or even whole of the world.

A WA> is two or more 6A>s connected together. !he 6A>s can be many miles apart.

!o cover great distances, WA>s may transmit data over leased high&speed phone lines or wireless lin"

such as satellites.

)ultiple 6A>s can be connected together using devices such as bridges, routers, or gateways, which

enable them to share data.

!he world9s most popular WA> is the Internet.


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Ad/antages o' 8A7:

)essages can be sent very -uic"ly to anyone else on the networ". !hese messages can have pictures

sounds, or data included with them +called attachments.


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6.6. 7etor Con'iguration:roadly spea"ing, there are two types of networ" configuration, peer&to&peer networ"s and client4serve

networ"s.

Peer-to-peer netors are more commonly implemented where less than ten computers are involved an

where strict security is not necessary. All computers have the same status, hence the term 9peer9, and the

communicate with each other on an e-ual footing. =iles, such as word processing or spreadsheet documentscan be shared across the networ" and all the computers on the networ" can share devices, such as printers o

scanners, which are connected to any one computer.

Client#ser/er netors are more suitable for larger networ"s. A central computer, or 9server9, acts as thstorage location for files and applications shared on the networ". 1sually the server is a higher than averag

performance computer. !he server also controls the networ" access of the other computers which ar

referred to as the 9client9 computers. !ypically, teachers and students in a school will use the client computerfor their wor" and only the networ" administrator +usually a designated staff member will have access righ

to the server.


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ig: Client-,er/er netoring

. 7etoring Components:

7etor +nter'ace Card (7+C)5

A networ" interface card +>IC is a circuit board orcardthat is installed in a computer so that it can beconnected to a networ".

IC. !he >IC

prepares +formats and sends data, receives data, and controls data flow between the computer and the

networ". (n the transmit side, the >IC passes frames of data on to the physical layer, which transmits the

data to the physical lin". (n the receiver9s side, the >IC processes bits received from the physical layer and

processes the message based on its contents.

Hub:

3ub is a device that splits a networ" connection into multiple computers. It is li"e a distributio

center. When a computer re-uest information from a networ" or a specific computer, it sends the re-uest t

the hub through a cable. !he hub will receive the re-uest and transmit it to the entire networ" +ever

computer in the networ" including the originating computer. )ost of the computers on the networ" wi

ignore the re-uest. !he computer that the re-uest is being sent to will accept the data pac"et and send out

reply pac"et. !he reply pac"et will then be sent to every computer by the hub.

(ne problem with hubs is that they often cause collisions between pac"ets. As a result, data is lost i

transmission and must be re&sent.

,8+5C:

A netor sitchis a small hardware device that 2oins multiple computers together within one locaarea networ" +6A>.

A switch is a telecommunication device that receives a message from any device connected to it and

then transmits the message only to the device for which the message was meant + It don$t broadcast thereceived message to entire networ". !his ma"es the switch a more intelligent device than ahub+which

receives a message and then transmits it to all the other devices on its networ".
http://whatis.techtarget.com/definition/card-or-expansion-card-board-or-adapterhttp://whatis.techtarget.com/definition/card-or-expansion-card-board-or-adapterhttp://whatis.techtarget.com/definition/card-or-expansion-card-board-or-adapterhttp://compnetworking.about.com/cs/lanvlanwan/g/bldef_lan.htmhttp://compnetworking.about.com/cs/lanvlanwan/g/bldef_lan.htmhttp://en.wikipedia.org/wiki/Ethernet_hubhttp://whatis.techtarget.com/definition/card-or-expansion-card-board-or-adapterhttp://compnetworking.about.com/cs/lanvlanwan/g/bldef_lan.htmhttp://compnetworking.about.com/cs/lanvlanwan/g/bldef_lan.htmhttp://en.wikipedia.org/wiki/Ethernet_hub


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#witches appear nearly identical to hubs,but a switch generally contains more intelligence +and a slightly

higher price tag than a hub.

1nli"e hubs, networ" switches are capable of inspecting datapac"ets as they are received,

determining the source and destination device of each pac"et, and forwarding them appropriately.

1nli"e hubs, switches can limit the traffic to and from each port so that each device connected to the

switch has a sufficient amount of bandwidth. You can thin" of a switch as a Bsmart hub.B #witches are moreadvanced than hubs and less capable than routers.

$%U5E$ :

A router is a device that 2oins two different networ"s together. A routeris a device that forward

data pac"etsbetween computer networ"s

A router is connected to two or more data lines from different networ"s. When a data pac"et comes i

one of the lines, the router reads the address information in the pac"et to determine its ultimate destination

!hen, using information in its routing table, it directs the pac"et to the next networ" on its 2ourney. 'outer

perform the Btraffic directingB functions on the Internet.A data pac"et is typically forwarded from one route

to another through the networ"s that constitute the internetwor" until it reaches its destination.

!%&E! :

A modem, short for modulator4demodulator, is a device that converts the digital signals generated by

computer into analog signals that can travel over conventional phone lines. !he modem at the receiving en

converts the analog signal bac" into a digital form that the computer can understand. !his is used to connecthe Internet.

A modem is a device that allows you to connect to your Internet service provider and browse th

Internet. ecause modems only provide one I0 address each, the best way to use a high&speed modem is tshare its services among computers.
http://compnetworking.about.com/cs/internetworking/g/bldef_hub.htmhttp://compnetworking.about.com/library/glossary/bldef-packet.htmhttp://www.techterms.com/definition/hubhttp://www.techterms.com/definition/routerhttps://en.wikipedia.org/wiki/Data_packethttps://en.wikipedia.org/wiki/Computer_networkhttps://en.wikipedia.org/wiki/Routing_tablehttps://en.wikipedia.org/wiki/Internethttp://compnetworking.about.com/cs/internetworking/g/bldef_hub.htmhttp://compnetworking.about.com/library/glossary/bldef-packet.htmhttp://www.techterms.com/definition/hubhttp://www.techterms.com/definition/routerhttps://en.wikipedia.org/wiki/Data_packethttps://en.wikipedia.org/wiki/Computer_networkhttps://en.wikipedia.org/wiki/Routing_tablehttps://en.wikipedia.org/wiki/Internet


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E5E$7E5 CA4LE 5

To set up a wired network, Ethernet cables are needed that allow the transmission of

data from one networked device to another. Category 5 (Cat 5) cable is one of the most

common types of Ethernet cable. hen connecting computers to a network, one end of the

Cat 5 cable is plugged into the computer!s "#C and the other is plugged into the hub, switch,

or router.

$EPEA5E$, :

A repeateris a networ"device that is used to regenerate signals +strength that are wea"ened or distorted by

transmission over long distances and through areas with high levels of electromagnetic interference + segment beyond its physical limits +e.g.


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layer. ridges read the )AC header of each frame to determine on which side of the bridge the destination

device is located, the bridge then repeats the transmission to the segment where the device is located.

8APs (8ireless Access Point):

A wireless networ" adapter card with a transceiver sometimes called an access point, broadcasts and receivesignals to and from the surrounding computers and passes bac" and forth between the wireless computers

and the cabled networ".

Access points act as wireless hubs to lin" multiple wireless >ICs into a single subnet. Access points alsohave at least one fixed


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We shall denote a binary number with a suffix B. #ome programming languages denote binary numbers wit

prefix 0b+e.g., 0b1001000, or prefix bwith the bits -uoted +e.g., b'10001111'.

A binary digit is called a bit. ) 7umer ,"stem

3exadecimal number system uses / symbols5 , /, :, D, F, E, , G, H, M, A, , C, %,


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/4/ -uotientN/ remainderN

/4/ -uotientN remainderN/ +-uotientN stop

3ence, :/% N /E3

@. Exercises (7umer ,"stems Con/ersion)

/. Convert the following decimalnumbers into binaryand he$adecimalnumbers5

/. 108

:. 4848

D. 9000

:. Convert the following binary numbers into hexadecimal and decimal numbers5

/. 1000011000

:. 10000000

D. 101010101010

D. Convert the following hexadecimal numbers into binary and decimal numbers5

/. ABCDE

:. 1234

D. 80F

F. Q!(%(R more

+75$%&UC5+%7 %7 4+7A$:

4its:

)he smallest unit of data on a binar! computer is a single bit. #ince a single bit is capable of

representing only two different values +typically ero or one you may get the impression that there are a

very small number of items you can represent with a single bit. >ot trueS !here are an infinite number of

items you can represent with a single bit.

7iles:

& nibble is a collection of four bits.

It wouldn9t be a particularly interesting data structure except for two items5 C% +binary coded decimal

numbers and hexadecimal numbers. It ta"es four bits to represent a single C% or hexadecimal digit.

With a nibble, we can represent up to / distinct values. In the case of hexadecimal numbers, the values , /:, D, F, E, , G, H, M, A, , C, %,


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anything smaller re-uires that you read the byte containing the data and mas" out the unwanted bits. !he bit

in a byte are normally numbered from ero to seven using the convention shown below5

4it = is the lo3 order bitor least significant bit; 4it ? is the high order bitor most significant bito' the

"te. We9ll refer to all other bits by their number.

>ote that a byte also contains exactly two nibbles5

its ..D comprise the lo3 order nibble, bits F.G form the high order nibble. #ince a byte contains

exactly two nibbles, byte values re-uire two hexadecimal digits.

#ince a byte contains eight bits, it can represent : H, or :E, different values. @enerally, we9ll use a byte torepresent numeric values in the range ...:EE, signed numbers in the range &/:H...7/:G +see B#igned and

1nsigned >umbersB , A#CII4I) character codes, and other special data types re-uiring no more than :E

different values. )any data types have fewer than :E items so eight bits is usually sufficient.

8ords:

A word is a group of / bits. We9ll number the bits in a word starting from ero on up to fifteen. !he b

numbering appears below5

6i"e the byte, bit is the low order bit and bit /E is the high order bit. When referencing the other bits in a

word use their bit position number.

>otice that a word contains exactly two bytes. its through G form the low order byte, bits H through /Eform the high order byte5

With / bits, you can represent :/+E,ED different values. !hese could be the values in the range..E,EDE +or, as is usually the case, &D:,GH..7D:,GG or any other data type with no more than E,ED

values. !he three ma2or uses for words are integer values, offsets, and segment values.

Words can represent integer values in the range ...E,EDE or &D:,GHD:,GG. 1nsigned numeric

values are represented by the binary value corresponding to the bits in the word. #igned numeric values use


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the two9s complement form for numeric values. #egment values, which are always / bits long, constitute

the paragraph address of a code, data, extra, or stac" segment in memory.

&oule 8ords:

A double word is exactly what its name implies, a pair of words. !herefore, a double word -uantity is D: bitlong as shown below5

>aturally, this double word can be divided into a high order word and a low order word, or four differen

bytes, or eight different nibbles.

%ouble words can represent all "inds of different things. =irst and foremost on the list is a segmentedaddress. Another common item represented with a double word is a D:&bit integer value +whic

allows unsigned numbers in the range ...F,:MF,MG,:ME or signed numbers in the rang

&:,/FG,FHD,FH...:,/FG,FHD,FG. D:&bit floating point values also fit into a double word. )ost othe time, we9ll use double words to hold segmented addresses

>. 4+7A$ $EP$E,E75A5+%7 %7 +75E3E$,:

Integers are hole numbers or "i$ed%point numbers with the radix point "i$ed after the leas

significant bit. !hey are contrast to real numbersor "loating%point numbers, where the position of the radipoint varies. It is important to ta"e note that integers and floating&point numbers are treated differently i

computers. !hey have different representation and are processed differently +e.g., floating&point numbers ar

processed in a so&called floating&point processor. =loating&point numbers will be discussed later.

Computers use a "i$ed number o" bitsto represent an integer. !he commonly&used bit&lengths for integers arH&bit, /&bit, D:&bit or F&bit.

5here are to representation schemes 'or integers:

/. Unsigned Integers: can represent ero and positive integers.

:. %igned Integers: can represent ero, positive and negative integers. !hree representation scheme

had been proposed for signed integers5

/. #ign&)agnitude representation

:. /9s Complement representationD. :9s Complement representation

You, as the programmer, need to decide on the bit&length and representation scheme for your integersdepending on your application9s re-uirements. #uppose that you need a counter for counting a small -uantit

from up to :, you might choose the H&bit unsigned integer scheme as there is no negative number

involved.

1. Unsigned +ntegers :


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1nsigned integers can represent ero and positive integers, but not negative integers.

!he value of an unsigned integer is interpreted as Bthe magnitude o" its underlying binary patternB.

$ange: An unsigned integer containing n bits can have a value between = and n 1.


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.1. #igned Integers in T,ign-!agnitude $epresentationB

In sign&magnitude representation5

!he most&significant bit +msb is the sign bit, with value of representing positive integer and

representing negative integer.

!he remaining n&/ bits represent the magnitude +absolute value of the integer. !he absolute value o

the integer is interpreted as Bthe magnitude of the +n&/&bit binary patternB.

!he largest and smallest signed integer that can be represented by using #igned )agnitude method o

> bits is

((7 1) 1) to (7 1)1


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5he draacs o' sign-magnitude representation are5

/. !here are two representations +0000 0000Band 1000 0000B for the number ero, which coul

lead to inefficiency and confusion.

0ositive and negative integers need to be processed separately.

.. #igned Integers in1s Complement $epresentation

In /9s complement representation5

Again, the most significant bit +msb is the sign bit, with value of representing positive integers an

/ representing negative integers.

!he remaining n&/ bits represents the magnitude of the integer, as follows5

o =or positive integers, the absolute value of the integer is e-ual to Bthe magnitude of the + n&/

bit binary patternB.o =or negative integers, the absolute value of the integer is e-ual to Bthe magnitude of th

complement+inverse of the +n&/&bit binary patternB +hence called /9s complement.

!he largest and smallest signed integer that can be represented by using #igned )agnitude method o

> bits is

(7 1) 1 to (7 1)1


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.6 #igned Integers ins Complement $epresentation

In :9s complement representation5

Again, the most significant bit +msb is the sign bit, with value of representing positive integers an

/ representing negative integers.

!he remaining n&/ bits represents the magnitude of the integer, as follows5

o =or positive integers, the absolute value of the integer is e-ual to Bthe magnitude of the + n&/

bit binary patternB.

o =or negative integers, the absolute value of the integer is e-ual to Bthe magnitude of th

complementof the +n&/&bit binary patternplus oneB +hence called :9s complement.

+' a signed integer has n itsD it can contain a numer eteen - n - 1and (n - 1- 1).

Ad/antage o/er ,ign-!agnitude representation and 1s Complement representation are

/. !here is only one representation for the number ero in :9s complement, instead of tw

representations in sign&magnitude and /9s complement.:. 0ositive and negative integers can be treated together in addition and subtraction. #ubtraction can b

carried out using the Baddition logicB.


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EFA!PLE,:


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E% U / /

&E% U //// /// +7

&&&&&&&&&&&&&&// // U % +discard carry & (

egative Integers5 #uppose thatn=8# -65D - 5D = -65D! + -5D= -"0D

&E% U /// ////&E% U //// /// +7

&&&&&&&&&&&&&&

/// // U &G% +discard carry & (

ecause of the "i$ed precision +i.e., "i$ed number o" bits, an n&bit :9s complement signed integer has certain range. =or example, for n=8, the range of :9s complement signed integers is -128to +12". %urin

addition +and subtraction, it is important to chec" whether the result exceeds this range, in other words

whether over"loor under"lohas occurred.


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00010011 + 00111110 = 01010001 1 1 1 1 1 carries 0 0 0 1 0 0 1 1 N /M+base /+ 0 0 1 1 1 1 1 0 N :+base /

0 1 0 1 0 0 0 1 N H/+base /

7ote: !he rules of binary addition +without carries are the same as the truths of the F%$gate.

$ules o' 4inar" ,utraction

0 - 0 = 0

0 - 1 = 1, and borrow / from the next more significant bit

1 - 0 = 1

1 - 1 = 0

&or e$ample#

00100101 - 00010001 = 00010100 0 borros 0 0 1 10 0 1 0 1 N DG+base /- 0 0 0 1 0 0 0 1 N /G+base /

0 0 0 1 0 1 0 0 N :+base /

00110011 - 00010110 = 00011101 010 1 borros

0 0 1 1 0 10 1 1

N E/+base /- 0 0 0 1 0 1 1 0 N ::+base /

0 0 0 1 1 1 0 1 N :M+base /

$ules o' 4inar" !ultiplication

0 x 0 = 0

0 x 1 = 0

1 x 0 = 0

1 x 1 = 1, and no carry or borrow bits

&or e$ample#

00101001 00000110 = 11110110 0 0 1 0 1 0 0 1 N F/+base / 0 0 0 0 0 1 1 0 N +base /

0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1

0 0 1 0 1 0 0 1
http://academic.evergreen.edu/projects/biophysics/technotes/program/logic.htm#gateshttp://academic.evergreen.edu/projects/biophysics/technotes/program/logic.htm#gates


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0 0 1 1 1 1 0 1 1 0 N :F+base /

00010111 00000011 = 01000101 0 0 0 1 0 1 1 1 N :D+base / 0 0 0 0 0 0 1 1 N D+base /

1 1 1 1 1 carries0 0 0 1 0 1 1 1

0 0 0 1 0 1 1 1

0 0 1 0 0 0 1 0 1 N M+base /

7ote: !he rules of binary multiplication are the same as the truths of the A7&gate.

Another !ethod: inary multiplication is the same as repeated binary additionL add the multicand to itself

the multiplier number of times.

&or e$ample#

00001000 00000011 = 00011000 1 carries 0 0 0 0 1 0 0 0 N H+base / 0 0 0 0 1 0 0 0 N H+base /+ 0 0 0 0 1 0 0 0 N H+base /

0 0 0 1 1 0 0 0 N :F+base /

4inar" &i/ision

inary division is the repeated process of subtraction, 2ust as in decimal division.

&or e$ample#

00101010 $ 00000110 = 00000111 1 1 1 N G+base /

1 1 0 0 0 1 10 1 0 1 0 N F:+base / - 1 1 0 N +base /

1 borros

1 010 1

- 1 1 0

1 1 0

- 1 1 0

0

10000111 $ 00000101 = 00011011 1 1 0 1 1 N :G+base /
http://academic.evergreen.edu/projects/biophysics/technotes/program/logic.htm#gateshttp://academic.evergreen.edu/projects/biophysics/technotes/program/logic.htm#gateshttp://academic.evergreen.edu/projects/biophysics/technotes/program/logic.htm#gates


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1 0 1 1 0 0 10 0 1 1 1 N /DE+base / - 1 0 1 N E+base /

1 1 10

- 1 0 1

1 1

- 0

1 1 1

- 1 0 1

1 0 1

- 1 0 1

0

7otes

4inar" 7umer ,"stem#ystem %igits5 and /

it +short for binary digit5 A single binary digit

6# +least significant bit5 !he rightmost bit)# +most significant bit5 !he leftmost bit

1pper yte +or nybble5 !he right&hand byte +or nybble of a pair

6ower yte +or nybble5 !he left&hand byte +or nybble of a pair

4inar" EGui/alents

/ >ibble +or nibble N F bits

/ yte N : nibbles N H bits/ ilobyte + N /:F bytes

/ )egabyte +) N /:F "ilobytes N /,FH,EG bytes

/ @igabyte +@ N/:F megabytes N /,GD,GF/,H:F bytes

Logical %perations on 4its

!here are four main logical operations we9ll need to perform on hexadecimal and binary numbers5 A>%, ('

V(' +exclusive&or, and >(!.

!he logical A>% operation is a dyadic operation +meaning it accepts exactly two operands. !hese operandare single binary +base : bits. !he A>% operation is5

and N

and / N

/ and N / and / N /

A compact way to represent the logical A>% operation is with a truth table. A truth table ta"es the followin

form5


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A>% !ruth !able

A7& = 1

/ /

!he logical A>% operation is, BIf the first operand is one and the second operand is one, the result is oneL

otherwise the result is ero.B

!he logical (' operation is also a dyadic operation. Its definition is5

or N

or / N // or N /

/ or / N /

!he truth table for the (' operation ta"es the following form5

(' !ruth !able%$ = 1

/

/ / /

Collo-uially, the logical (' operation is, BIf the first operand or the second operand +or both is one, the

result is oneL otherwise the result is ero.B !his is also "nown as the inclusive&(' operation.

!he logical V(' +exclusive&or operation is also a dyadic operation. It is defined as follows5

xor N xor / N // xor N /

/ xor / N

!he truth table for the V(' operation ta"es the following form5

V(' !ruth !able

F%$ = 1

/

/ /

In (! operation is a monadic operation +meaning it accepts only one operand. It is5


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>(! N /

>(! / N

!he truth table for the >(! operation ta"es the following form5

>(! !ruth !able

7%5 = 1

/

3enerations o' Computer languages:

0rogramming languages are use to write application programs which are used by end users.. !h

development of programming languages has improved considerably with the ease and ability o

programmers to write powerful applications programs that can solve any tas" in the world today.


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Unit-1

Examples:

Architecture specific binary delivered on #witches, 0atch 0anelsand4or !ape.

. ,econd-generation programming language (3L) Asseml"

!hese were developed in the early /MEs with the ability to use acronyms to speed programming and coding

of programs. !hey were "nown generational languages were called asseml" languages. !hey had thecapability to performs operation such li"e add, sum. 6i"e machine languages, assembly languages were

designed for specific machine and microprocessor, this implies that the program cannot be move from one

computer architecture without writing the code which means learning another language where you are totransfer the programs.

Introduced in the /MEs

Written by a programmer in an intermediate instruction language which is later compiled into binary

instructions

#pecific to platform architecture

%esigned to support logical structure, debugging

%efined by three language elements5 (pcodes +C01 Instructions, %ata #ections +*ariable%efinitions and %irective +)acros

Examples:

Almost every C01 architecture has a companion assembly language. )ost commonly in use today are

'I#C, CI#C and xH as that is what our embedded systems and des"top computers use.

6. 5hird-generation programming language (63L) !odern

!hird generation languages are the primary languages used in general purpose programming today +high

level computer languages popularly "nown as Drd generation language +D@6#. !hey each vary -uite widelyin terms of their particular abstractions and syntax. 3owever, they all share great enhancements in logical

structure over assembly language.

Introduced in the /MEs+between /ME and /MD

%esigned around ease of use for the programmer

%riven by desire for reduction in bugs, increases in code reuse

ased on natural language

(ften designed with in mind

Examples:Drdgeneration languages include the following

C, C77, C, Xava, asic, =('!'A>, C((6.

%$5$A7 ormula 5ranslation

=('!'A> was developed in /ME to provide easier way for scientific and engineering application and theswere especially useful for processing >umeric data.

C%4%L Common 4usiness %riented Languages
http://en.wikipedia.org/wiki/ENIAChttp://en.wikipedia.org/wiki/Atanasoff%E2%80%93Berry_Computerhttp://en.wikipedia.org/wiki/Z3_(computer)http://en.wikipedia.org/wiki/Second-generation_programming_languagehttp://en.wikipedia.org/wiki/Third-generation_programming_languagehttp://en.wikipedia.org/wiki/ENIAChttp://en.wikipedia.org/wiki/Atanasoff%E2%80%93Berry_Computerhttp://en.wikipedia.org/wiki/Z3_(computer)http://en.wikipedia.org/wiki/Second-generation_programming_languagehttp://en.wikipedia.org/wiki/Third-generation_programming_language


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C%4%L came into use in the early /M. It was designed with business administration in mind for

processing large data types with alphanumeric characters which were mixture of alphabet and data and does

repetitive tas"s li"e payroll. !he other language was A#IC. !hese were the early computer programminglanguages in the early history of computers, since then there has been improvement and this will be discuss

later.

. ourth-generation programming language Application ,peci'ic

A fourth generation language is designed with ma"ing problems in a specific domain simple to implemen

!his has the advantage of greatly reducing development time cost. At the same time there is the disadvantag

of increasing developer learning cost.

Introduced in the /MGs, !erm coined by

%riven by the need to enhance developer productivity

=urther from the machine

Closer to the domain

#ome examples5 #6, #A#, )A!6A9s @1I%ot in common use

#ome examples5 0rolog, )ercury
http://oderog.hubpages.com/hub/Computer-history-and-generationshttp://oderog.hubpages.com/hub/Computer-history-and-generations

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