TyroCity: Computer Notes

Number System

TyroCity.com — Sat, 12 Jul 2014 05:41:42 +0000

Conversion Techniques

1. Decimal to
a. Binary

/2 (Integer Part)
*2 (Decimal Part)

b. Octal

/8 (Integer Part)
*8 (Decimal Part)

c. Hexadecimal

/16 (Integer Part)
*16 (Decimal Part)

2. Binary to
a. Octal

Table (3-bit)

b. Decimal

*2n For eg. (1011)2 =1*23+0*22 +1*21+1*20

c. Hexadecimal

Table (4-bit)

3. Octal to
a. Binary

Table (3-bit)

b. Decimal

*8n For eg. (2341)8 =2*83+3*82 +4*81+1*80

c. Hexadecimal

Construct table of:
- Octal-Binary (3Bit)
- Binary-hexadecimal (4Bit)

4. Hexadecimal to

a. Binary

Table (4-bit)

b. Octal

Construct table of:
- Hexa-Binary (4Bit)
- Binary-Octal (3Bit)

c. Decimal

*16n For eg. (12A8)2 =1*163+2*162 +10*161+8*160

1’s and 2’s Complement

9’s and 10’s Complement

Computer Science Grade-11 2069

TyroCity.com — Sun, 18 Aug 2013 05:41:42 +0000

Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.

Full Marks:- 75
Pass Marks:- 27
Time:- 3hrs.

Group A
Long answer questions

Attempt any three questions. 3×10=30

What is an operating system? Explain the functions of operating system.
What is memory in the computer system? Explain primary and secondary memory.
What is programming? Differentiate between compiler and interpreter.
What is Boolean algebra? Describe AND gate, OR gate, NOT gate and NAND gate symbol and Truth Table.

Group B
Short answer questions
Attempt any nine questions. 9×5=45

Why computer is known as versatile and diligent device? Explain.
What is mobile computing? Explain. Or Differentiate between analog and digital computer.
Convert (110111101)2 binary number into octal number.
What is BUS in terms of computer architecture? Explain.
Differentiate between Impact and Non-impact printers with examples.
What is internet? Write down the uses of internet. Or Explain the features of word processor.
What is web page? List the features of web page. Or Write down the advantages and disadvantages of DBMS. (Old)
What is CPU? Write down the functions of CPU.
Explain the types of programming errors with examples.
Subtract (1100)2 from (1111)2 using 1st and 2nd complement method.
Write short notes on:
- Modem
- Trackball

Computer XI Questions

TyroCity.com — Sun, 18 Aug 2013 05:41:42 +0000

Questions

Model Question for Computer Science Class 11

TyroCity.com — Sun, 18 Aug 2013 05:41:42 +0000

GRADE : 11
FOR : 2070
Time : 3hrs
F.M. : 75
P.M : 27

Group A (Long Answer Question)
Attempt ALL the questions. [3 × 10 = 30]

Draw a well-labeled diagram of typical architecture of a computer system and explain the main function of Control Unit and ALU. [4+3+3] 2.a. What is an operating system ? Explain any three function of an operating system. [1 + 6] 2.b. The “WiMP” environment is much more user-friendly, why ?

OR
2.a. What is cell addressing and explain different types of cell addressing used in spreadsheet. [5]
2.b. Write a tag to design your personal web page to link photo family, background and banner page using frame. [5]

3.a. Define flowchart and pseudocode. Explain their significance in programming. [5]

3.b. Write a pseudocode to accept any three numbers and output the largest among them. [5]

Group B (Short Answer Questions)
Attempt any NINE questions. [9 × 5 = 45]

Classify the computers according to their generation based on the technology used. [5]
Differentiate between analogue and digital computer, explain with examples. [5]
What do you mean by number system? Why do digital computers use binary numbers for their operation ? [2 + 3]
Convert these numbers. [5]
- (126)10 = (?) 2
- (11011)2 = (?) 10
- (57)8 = (?) 2
Perform following operations.
- 1011 – 1001
- 1110 + 1110
State the Demorgan’s theorem and verify it. [5]
What are logic gates? Construct the truth table of NOR operation. [5]
Write short notes on (any two) : [5]
- IDE
- SCSI
- Wave Camera
What are uses of internet ? Write any five search engine name. [5]
Differentiate between System Software and Application Software with examples. [5]
What are DPT features in MS-Words? Write three features of Presentation Packages. [2 + 3]
Write an algorithm and flowchart to print the word “Hello” ten times using “while loop” [5]

Communication And Computer Network

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Introduction to communication and computer network

Today computer is available in many offices and homes and therefore there is a need to share data and programs among various computers with the advancement of data communication facilities. The communication between computers has increased and it thus it has extended the power of computer beyond the computer room. Now a user sitting at one place can communicate computers of any remote sites through communication channel. The aim of this chapter is to introduce you the various aspects of computer network.

Objectives

After going through this lesson you will be in a position to:

explain the concept of data communication
understand the use of computer network
identify different components of computer network
identify different types of network
explain communication protocols
understand what is internet and email and its uses in modern communication
appreciate the use of satellite communication.

Data communication

We all are acquainted with some sorts of communication in our day to day life. For communication of information and messages we use telephone and postal communication systems. Similarly data and information from one computer system can be transmitted to other systems across geographical areas. Thus data transmission is the movement of information using some standard methods. These methods include electrical signals carried along a conductor, optical signals along an optical fibers and electromagnetic areas.

Suppose a manager has to write several letters to various clients. First he has to use his PC and Word Processing package to prepare his letter. If the PC is connected to all the client’s PCs through networking, he can send the letters to all the clients within minutes. Thus irrespective of geographical areas, if PCs are connected through communication channel, the data and information, computer files and any other program can be transmitted to other computer systems within seconds. The modern form of communication like e-mail and Internet is possible only because of computer networking.

Basic elements of a communication system

The following are the basic requirements for working of a communication system.

A sender (source) which creates the message to be transmitted.
A medium that carries the message.
A receiver(sink) which receives the message.

In data communication four basic terms are frequently used. They are:

- Data: A collection of facts in raw forms that become information after processing.
- Signals: Electric or electromagnetic encoding of data.
- Signaling: Propagation of signals across a communication medium.
- Transmission: Communication of data achieved by the processing of signals.

Communication protocols

You may be wondering how do the computers send and receive data across communication links. The answer is data communication software. It is this software that enables us to communicate with other systems. The data communication software instructs computer systems and devices as to how exactly data is to be transferred from one place to another. The procedure of data transformation in the form of software is commonly called protocol.

The data transmission software or protocols perform the following functions for the efficient and error free transmission of data.

Data sequencing: A long message to be transmitted is broken into smaller packets of fixed size for error free data transmission.

Data routing: It is the process of finding the most efficient route between source and destination before sending the data.

Flow control: All machines are not equally efficient in terms of speed. Hence the flow control regulates the process of sending data between fast sender and slow receiver.

Error control: Error detecting and recovering is the one of the main function of communication software. It ensures that data are transmitted without any error.

Data transmission modes

There are three ways for transmitting data from one point to another

1. Simplex: In simplex mode the communication can take place in one direction. The receiver receives the signal from the transmitting device. In this mode the flow of information is Uni.-directional. Hence it is rarely used for data communication.

2. Half-duplex: In half-duplex mode the communication channel is used in both directions, but only in one direction at a time. Thus a half-duplex line can alternately send and receive data.

3. Full-duplex: In full duplex the communication channel is used in both directions at the same time. Use of full-duplex line improves the efficiency as the line turn-around time required in half-duplex arrangement is eliminated. Example of this mode of transmission is the telephone line.

Digital and analog transmission

Data is transmitted from one point to another point by means of electrical signals that may be in digital and analog form. So one should know the fundamental difference between analog and digital signals. In analog signal the transmission power varies over a continuous range with respect to sound, light and radio waves. On the other hand a digital signal may assume only discrete set of values within a given range. Examples are computer and computer related equipment. Analog signal is measured in Volts and its frequency in Hertz (Hz). A digital signal is a sequence of voltage represented in binary form. When digital data are to be sent over an analog form the digital signal must be converted to analog form. So the technique by which a digital signal is converted to analog form is known as modulation. And the reverse process, that is the conversion of analog signal to its digital form, is known as demodulation. The device, which converts digital signal into analog, and the reverse, is known as modem.

Asynchronous and synchronous transmission

Data transmission through a medium can be either asynchronous or synchronous. In asynchronous transmission data is transmitted character by character as you go on typing on a keyboard. Hence there is irregular gaps between characters. However, it is cheaper to implement, as you do not have to save the data before sending. On the other hand, in the synchronous mode, the saved data is transmitted block by block. Each block can contain many characters. Synchronous transmission is well suited for remote communication between a computer and related devices like card reader and printers.

Following are the major communication devices used to day.

Wire pairs: Wire pairs are commonly used in local telephone communication and for short distance digital data communication. They are usually made up of copper and the pair of wires is twisted together. Data transmission speed is normally 9600 bits per second in a distance of 100 meter.

Coaxial cables: Coaxial cable is groups of specially wrapped and insulted wires that are able to transfer data at higher rate. They consist of a central copper wire surrounded by an insulation over which copper mesh is placed. They are used for long distance telephone lines and local area network for their noise immunity and faster data transfer.

Microwave: Microwave system uses very high frequency radio signals to transmit data through space. The transmitter and receiver of a microwave system should be in line-of-sight because the radio signal cannot bend. With microwave very long distance transmission is not possible. In order to overcome the problem of line of sight and power amplification of weak signal, repeaters are used at intervals of 25 to 30 kilometers between the transmitting and receiving end.

Communication satellite: The problem of line-sight and repeaters are overcome by using satellites which are the most widely used data transmission media in modern days. A communication satellite is a microwave relay station placed in outer space. INSAT-1B is such a satellite that can be accessible from anywhere in India. In satellite communication, microwave signal is transmitted from a transmitter on earth to the satellite at space. The satellite amplifies the weak signal and transmits it back to the receiver. The main advantage of satellite communication is that it is a single microwave relay station visible from any point of a very large area. In microwave the data transmission rate is 16 giga bits per second. They are mostly used to link big metropolitan cities.

In-text questions 1

1. What is communication protocol?

2. What is the difference between asynchronous and synchronous transmission?

3. State whether True or False

The basic requirements for working of a communication system are sender medium and receiver.
Electric or Electromagnetic encoding of data is called Transmission.
In full duplex the communication channel is used in both directions at the same time.
Analog signal is measured in Volts and its frequency in Hertz
The technique by which a digital signal is converted to analog form is known as modulation.

Computer network

A computer network is an interconnection of various computer systems located at different places. In computer network two or more computers are linked together with a medium and data communication devices for the purpose of communicating data and sharing resources. The computer that provides resources to other computers on a net
work is known as server. In the network the individual computers, which access shared network resources, are known as workstations or nodes.
Computer Networks may be classified on the basis of geographical area in two broad categories.

Local area network (LAN)
Wide area network (WAN)

Local area network

Networks used to interconnect computers in a single room, rooms within a building or buildings on one site are called Local Area Network (LAN). LAN transmits data with a speed of several megabits per second (106 bits per second). The transmission medium is normally coaxial cables.

LAN links computers, i.e., software and hardware, in the same area for the purpose of sharing information. Usually LAN links computers within a limited geographical area because they must be connected by a cable, which is quite expensive. People working in LAN get more capabilities in data processing, work processing and other information exchange compared to stand-alone computers. Because of this information exchange most of the business and government organizations are using LAN.

Major characteristics of LAN

Every computer has the potential to communicate with any other computers of the network
High degree of interconnection between computers
Easy physical connection of computers in a network
Inexpensive medium of data transmission
High data transmission rate

Advantages

The reliability of network is high because the failure of one computer in the network does not effect the functioning for other computers.
Addition of new computer to network is easy.
High rate of data transmission is possible.
Peripheral devices like magnetic disk and printer can be shared by other computers.

Disadvantages

If the communication line fails, the entire network system breaks down.

Use of LAN

Followings are the major areas where LAN is normally used

File transfers and Access
Word and text processing
Electronic message handling
Remote database access
Personal computing
Digital voice transmission and storage

Wide area network

The term Wide Area Network (WAN) is used to describe a computer network spanning a regional, national or global area. For example, for a large company the head quarters might be at Delhi and regional branches at Bombay, Madras, Bangalore and Calcutta. Here regional centers are connected to head quarters through WAN. The distance between computers connected to WAN is larger. Therefore the transmission medium used are normally telephone lines, microwaves and satellite links.

Characteristics of WAN

Followings are the major characteristics of WAN.

1. Communication facility: For a big company spanning over different parts of the country the employees can save long distance phone calls and it overcomes the time lag in overseas communications. Computer conferencing is another use of WAN where users communicate with each other through their computer system.

2. Remote data entry: Remote data entry is possible in WAN. It means sitting at any location you can enter data, update data and query other information of any computer attached to the WAN but located in other cities. For example, suppose you are sitting at Madras and want to see some data of a computer located at Delhi, you can do it through WAN.

3. Centralized information: In modern computerized environment you will find that big organizations go for centralized data storage. This means if the organization is spread over many cities, they keep their important business data in a single place. As the data are generated at different sites, WAN permits collection of this data from different sites and save at a single site.

Examples of WAN

1. Ethernet: Ethernet developed by Xerox Corporation is a famous example of WAN. This network uses coaxial cables for data transmission. Special integrated circuit chips called controllers are used to connect equipment to the cable.

2. Aparnet: The Aparnet is another example of WAN. It was developed at Advanced Research Projects Agency of U. S. Department. This Network connects more than 40 universities and institutions throughout USA and Europe.

Difference between LAN and WAN

LAN is restricted to limited geographical area of few kilometers. But WAN covers great distance and operate nationwide or even worldwide.
In LAN, the computer terminals and peripheral devices are connected with wires and coaxial cables. In WAN there is no physical connection. Communication is done through telephone lines and satellite links.
Cost of data transmission in LAN is less because the transmission medium is owned by a single organization. In case of WAN the cost of data transmission is very high because the transmission medium used are hired, either telephone lines or satellite links.
The speed of data transmission is much higher in LAN than in WAN. The transmission speed in LAN varies from 0.1 to 100 megabits per second. In case of WAN the speed ranges from 1800 to 9600 bits per second (bps).
Few data transmission errors occur in LAN compared to WAN. It is because in LAN the distance covered is negligible.

Network topology

The term topology in the context of communication network refers to the way the computers or workstations in the network are linked together. According to the physical arrangements of workstations and nature of work, there are three major types of network topology. They are star topology, bus topology and ring topology.

Star topology

In star topology a number of workstations (or nodes) are directly linked to a central node (see, Fig. 4.3). Any communication between stations on a star LAN must pass through the central node. There is bi-directional communication between various nodes. The central node controls all the activities of the nodes. The advantages of the star topology are:

It offers flexibility of adding or deleting of workstations from the network.
Breakdown of one station does not affect any other device on the network.

The major disadvantage of star topology is that failure of the central node disables communication throughout the whole network.

Bus topology

In bus topology all workstations are connected to a single communication line called bus. In this type of network topology there is no central node as in star topology. Transmission from any station travels the length of the bus in both directions and can be received by all workstations. The advantage of the bus topology is that:

It is quite easy to set up.
If one station of the topology fails it does not affect the entire system.

The disadvantage of bus topology is that any break in the bus is difficult to identify.

Ring topology

In ring topology each station is attached nearby stations on a point to point basis so that the entire system is in the form of a ring. In this topology data is transmitted in one direction only. Thus the data packets circulate along the ring in either clockwise or anti-clockwise direction. The advantage of this topology is that any signal transmitted on the network passes through all the LAN stations. The disadvantage of ring network is that the breakdown of any one station on the ring can disable the entire system.

In-text questions 2

1. Differentiate between LAN and WAN.

2. What are the different types of network topology?

3. State True or False

Networks used to interconnect computers in a single room, rooms within a building or buildings on one site are called Wide Area Network (WAN).
The term Wide Area Network (WAN) is used to describe a computer network spanning a regional, national or global area.
The speed of data transmission is much higher in WAN than in LAN.
In star topology a number of workstations (or nodes) are directly linked to a central node.
The advantage of the bus topology is that, If one station of the topology fails it does not affect the entire system.

Internet

The Internet is a network of networks. Millions of computers all over the world are connected through the Internet. Computer users on the Internet can contact one another anywhere in the world. If your computer is connected to the Internet, you can connect to millions of computers. You can gather information and distribute your data. It is very much similar to the telephone connection where you can talk with any person anywhere in the world.

In Internet a huge resource of information is accessible to people across the world. Information in every field starting from education, science, health, medicine, history, and geography to business, news, etc. can be retrieved through Internet. You can also download programs and software packages from anywhere in the world. Due to the tremendous information resources the Internet can provide, it is now indispensable to every organization.

Origin of internet

In 1969 Department of Defense (DOD) of USA started a network called ARPANET (Advanced Research Projects Administration Network) with one computer at California and three at Utah. Later on other universities and R & D institutions were allowed to connect to the Network. APARNET quickly grew to encompass the entire American continent and became a huge success. Every university in the country wanted to become a part of ARPANET. So the network was broken into two smaller parts MILNET for managing military sites and ARPANET (smaller) for managing non-military sites. Around 1980, NSFNET (National Science Foundation Network) was created. With the advancement of modern communication facilities, other computers were also allowed to be linked up with any computer of NSFNET. By 1990 many computers were looking up to NSFNET giving birth to internet.

How internet functions

Internet is not a governmental organization. The ultimate authority of the Internet is the Internet Society. This is a voluntary membership organization whose purpose is to promote global information exchange. Internet has more than one million computers attached to it.

E-mail

E-mail stands for electronic mail. This is one of the most widely used features of Internet. Mails are regularly used today where with the help of postage stamp we can transfer mails anywhere in the world. With electronic mail the service is similar. But here data are transmitted through Internet and therefore within minutes the message reaches the destination may it be anywhere in the world. Therefore the mailing system is excessively fast and is being used widely for mail transfer.

In-text questions 3

What is internet?
What is e-mail?
How does internet function?

What you have learnt

In this lesson we discussed the importance and modes of communication through computers. Computers can communicate with one another through computer networking. There are two types of computer network: LAN and WAN. We discussed about the physical arrangements of computer and peripherals in network topology. There are three types of network topology: star topology, bus topology and ring topology. Also we discussed about Internet and e-mail.

Terminal questions

What is computer Network? What are its main objectives?
Differentiate between analog and digital transmission of data.
Explain in brief different communication media.
What is the difference between simplex and full-duplex transmission?

Feedback to in-text questions

In-text questions 1

1. The data communication software instructs computer systems and devices as to how exactly data is to be transferred from one place to another. The procedure of data transformation in the form of software is commonly called protocol.

2. In asynchronous transmission data is transmitted character by character as you go on typing on a keyboard. On the other hand, in the synchronous mode, the saved data is transmitted block by block.

True
False
True
True
True

In-text questions 2

1. LAN is restricted to limited geographical area whereas WAN covers great distance. In LAN the computer terminals and peripheral devices are connected with wires and coaxial cables whereas in WAN communication is done through telephone lines and satellite links. The speed of data transmission is much higher in LAN than in WAN.

2. There are three major types of network topology. They are star topology, bus topology and ring topology.

False
True
False
True
True

In-text questions 3

1. The Internet is a network of networks. Information in every field starting from education, science, health, medicine, history, and geography to business, news, etc. can be retrieved through Internet.

2. E-mail stands for electronic mail. Through e-mail we can transfer data anywhere in the world within seconds.

3. Internet is not a governmental organization. The ultimate authority of the Internet is the Internet Society. This is a voluntary membership organization whose purpose is to promote global information exchange.

MS Excel Functions

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

The following sections list all of the worksheet functions by category.

Database functions
Function Description
DAVERAGE- Returns the average of selected database entries
DCOUNT- Counts the cells that contain numbers in a database
DCOUNTA- Counts nonblank cells in a database
DGET- Extracts from a database a single record that matches the specified criteria
DMAX- Returns the maximum value from selected database entries
DMIN- Returns the minimum value from selected database entries
DPRODUCT- Multiplies the values in a particular field of records that match the criteria in a database
DSTDEV- Estimates the standard deviation based on a sample of selected database entries
DSTDEVP- Calculates the standard deviation based on the entire population of selected database entries
DSUM- Adds the numbers in the field column of records in the database that match the criteria
DVAR- Estimates variance based on a sample from selected database entries
DVARP- Calculates variance based on the entire population of selected database entries

Date and time functions
Function Description
DATE- Returns the serial number of a particular date
DATEVALUE- Converts a date in the form of text to a serial number
DAY- Converts a serial number to a day of the month
DAYS360- Calculates the number of days between two dates based on a 360-day year
EDATE- Returns the serial number of the date that is the indicated number of months before or after the start date
EOMONTH- Returns the serial number of the last day of the month before or after a specified number of months
HOUR- Converts a serial number to an hour
MINUTE- Converts a serial number to a minute
MONTH- Converts a serial number to a month
NETWORKDAYS- Returns the number of whole workdays between two dates
NOW- Returns the serial number of the current date and time
SECOND- Converts a serial number to a second
TIME- Returns the serial number of a particular time
TIMEVALUE- Converts a time in the form of text to a serial number
TODAY- Returns the serial number of today’s date
WEEKDAY- Converts a serial number to a day of the week
WEEKNUM- Converts a serial number to a number representing where the week falls numerically with a year
WORKDAY- Returns the serial number of the date before or after a specified number of workdays
YEAR- Converts a serial number to a year
YEARFRAC- Returns the year fraction representing the number of whole days between start_date and end_date

Engineering functions
Function Description
BESSELI- Returns the modified Bessel function In(x)
BESSELJ- Returns the Bessel function Jn(x)
BESSELK- Returns the modified Bessel function Kn(x)
BESSELY- Returns the Bessel function Yn(x)
BIN2DEC- Converts a binary number to decimal
BIN2HEX- Converts a binary number to hexadecimal
BIN2OCT- Converts a binary number to octal
COMPLEX- Converts real and imaginary coefficients into a complex number
CONVERT- Converts a number from one measurement system to another
DEC2BIN- Converts a decimal number to binary
DEC2HEX- Converts a decimal number to hexadecimal
DEC2OCT- Converts a decimal number to octal
DELTA- Tests whether two values are equal
ERF- Returns the error function
ERFC- Returns the complementary error function
GESTEP- Tests whether a number is greater than a threshold value
HEX2BIN- Converts a hexadecimal number to binary
HEX2DEC- Converts a hexadecimal number to decimal
HEX2OCT- Converts a hexadecimal number to octal
IMABS- Returns the absolute value (modulus) of a complex number
IMAGINARY- Returns the imaginary coefficient of a complex number
IMARGUMENT- Returns the argument theta, an angle expressed in radians
IMCONJUGATE- Returns the complex conjugate of a complex number
IMCOS- Returns the cosine of a complex number
IMDIV- Returns the quotient of two complex numbers
IMEXP- Returns the exponential of a complex number
IMLN- Returns the natural logarithm of a complex number
IMLOG10- Returns the base-10 logarithm of a complex number
IMLOG2- Returns the base-2 logarithm of a complex number
IMPOWER- Returns a complex number raised to an integer power
IMPRODUCT- Returns the product of from 2 to 29 complex numbers
IMREAL- Returns the real coefficient of a complex number
IMSIN- Returns the sine of a complex number
IMSQRT- Returns the square root of a complex number
IMSUB- Returns the difference between two complex numbers
IMSUM- Returns the sum of complex numbers
OCT2BIN- Converts an octal number to binary
OCT2DEC- Converts an octal number to decimal
OCT2HEX- Converts an octal number to hexadecimal

Financial functions
Function Description
ACCRINT- Returns the accrued interest for a security that pays periodic interest
ACCRINTM- Returns the accrued interest for a security that pays interest at maturity
AMORDEGRC- Returns the depreciation for each accounting period by using a depreciation coefficient
AMORLINC- Returns the depreciation for each accounting period
COUPDAYBS- Returns the number of days from the beginning of the coupon period to the settlement date
COUPDAYS- Returns the number of days in the coupon period that contains the settlement date
COUPDAYSNC- Returns the number of days from the settlement date to the next coupon date
COUPNCD- Returns the next coupon date after the settlement date
COUPNUM- Returns the number of coupons payable between the settlement date and maturity date
COUPPCD- Returns the previous coupon date before the settlement date
CUMIPMT- Returns the cumulative interest paid between two periods
CUMPRINC- Returns the cumulative principal paid on a loan between two periods
DB- Returns the depreciation of an asset for a specified period by using the fixed-declining balance method
DDB- Returns the depreciation of an asset for a specified period by using the double-declining balance method or some other method that you specify
DISC- Returns the discount rate for a security
DOLLARDE- Converts a dollar price, expressed as a fraction, into a dollar price, expressed as a decimal number
DOLLARFR- Converts a dollar price, expressed as a decimal number, into a dollar price, expressed as a fraction
DURATION- Returns the annual duration of a security with periodic interest payments
EFFECT- Returns the effective annual interest rate
FV- Returns the future value of an investment
FVSCHEDULE- Returns the future value of an initial principal after applying a series of compound interest rates
INTRATE- Returns the interest rate for a fully invested security
IPMT- Returns the interest payment for an investment for a given period
IRR- Returns the internal rate of return for a series of cash flows
ISPMT- Calculates the interest paid during a specific period of an investment
MDURATION- Returns the Macauley modified duration for a security with an assumed par value of $100
MIRR- Returns the internal rate of return where positive and negative cash flows are financed at different rates
NOMINAL- Returns the annual nominal interest rate
NPER- Returns the number of periods for an investment
NPV- Returns the net present value of an investment based on a series of periodic cash flows and a discount rate
ODDFPRICE- Returns the price per $100 face value of a security with an odd first period
ODDFYIELD- Returns the yield of a security with an odd first period
ODDLPRICE- Returns the price per $100 face value of a security with an odd last period
ODDLYIELD- Returns the yield of a security with an odd last period
PMT- Returns the periodic payment for an annuity
PPMT- Returns the payment on the principal for an investment for a given period
PRICE- Returns the price per $100 face value of a security that pays periodic interest
PRICEDISC- Returns the price per $100 face value of a discounted security
PRICEMAT- Returns the price per $100 face value of a security that pays interest at maturity
PV- Returns the present value of an investment
RATE- Returns the interest rate per period of an annuity
RECEIVED- Returns the amount received at maturity for a fully invested security
SLN- Returns the straight-line depreciation of an asset for one period
SYD- Returns the sum-of-years’ digits depreciation of an asset for a specified period
TBILLEQ- Returns the bond-equivalent yield for a Treasury bill
TBILLPRICE- Returns the price per $100 face value for a Treasury bill
TBILLYIELD- Returns the yield for a Treasury bill
VDB- Returns the depreciation of an asset for a specified or partial period by using a declining balance method
XIRR- Returns the internal rate of return for a schedule of cash flows that is not necessarily periodic
XNPV- Returns the net present value for a schedule of cash flows that is not necessarily periodic
YIELD- Returns the yield on a security that pays periodic interest
YIELDDISC- Returns the annual yield for a discounted security; for example, a Treasury bill
YIELDMAT- Returns the annual yield of a security that pays interest at maturity

Information functions
Function Description
CELL- Returns information about the formatting, location, or contents of a cell
ERROR.TYPE- Returns a number corresponding to an error type
INFO- Returns information about the current operating environment
ISBLANK- Returns TRUE if the value is blank
ISERR- Returns TRUE if the value is any error value except #N/A
ISERROR- Returns TRUE if the value is any error value
ISEVEN- Returns TRUE if the number is even
ISLOGICAL- Returns TRUE if the value is a logical value
ISNA- Returns TRUE if the value is the #N/A error value
ISNONTEXT- Returns TRUE if the value is not text
ISNUMBER- Returns TRUE if the value is a number
ISODD- Returns TRUE if the number is odd
ISREF- Returns TRUE if the value is a reference
ISTEXT- Returns TRUE if the value is text
N- Returns a value converted to a number
NA- Returns the error value #N/A
TYPE- Returns a number indicating the data type of a value

Logical functions
Function Description
AND- Returns TRUE if all of its arguments are TRUE
FALSE- Returns the logical value FALSE
IF- Specifies a logical test to perform
NOT- Reverses the logic of its argument
OR- Returns TRUE if any argument is TRUE
TRUE- Returns the logical value TRUE

Lookup and reference functions
Function Description
ADDRESS- Returns a reference as text to a single cell in a worksheet
AREAS- Returns the number of areas in a reference
CHOOSE- Chooses a value from a list of values
COLUMN- Returns the column number of a reference
COLUMNS- Returns the number of columns in a reference
GETPIVOTDATA- Returns data stored in a PivotTable
HLOOKUP- Looks in the top row of an array and returns the value of the indicated cell
HYPERLINK- Creates a shortcut or jump that opens a document stored on a network server, an intranet, or the Internet
INDEX- Uses an index to choose a value from a reference or array
INDIRECT- Returns a reference indicated by a text value
LOOKUP- Looks up values in a vector or array
MATCH- Looks up values in a reference or array
OFFSET- Returns a reference offset from a given reference
ROW- Returns the row number of a reference
ROWS- Returns the number of rows in a reference
RTD- Retrieves real-time data from a program that supports COM automation(Automation: A way to work with an application’s objects from another application or development tool. Formerly called OLE Automation, Automation is an industry standard and a feature of the Component Object Model (COM).)
TRANSPOSE- Returns the transpose of an array
VLOOKUP- Looks in the first column of an array and moves across the row to return the value of a cell

Math and trigonometry functions
Function Description
ABS- Returns the absolute value of a number
ACOS- Returns the arccosine of a number
ACOSH- Returns the inverse hyperbolic cosine of a number
ASIN- Returns the arcsine of a number
ASINH- Returns the inverse hyperbolic sine of a number
ATAN- Returns the arctangent of a number
ATAN2- Returns the arctangent from x- and y-coordinates
ATANH- Returns the inverse hyperbolic tangent of a number
CEILING- Rounds a number to the nearest integer or to the nearest multiple of significance
COMBIN Returns the number of combinations for a given number of objects
COS- Returns the cosine of a number
COSH- Returns the hyperbolic cosine of a number
DEGREES- Converts radians to degrees
EVEN- Rounds a number up to the nearest even integer
EXP- Returns e raised to the power of a given number
FACT- Returns the factorial of a number
FACTDOUBLE- Returns the double factorial of a number
FLOOR- Rounds a number down, toward zero
GCD- Returns the greatest common divisor
INT- Rounds a number down to the nearest integer
LCM- Returns the least common multiple
LN- Returns the natural logarithm of a number
LOG- Returns the logarithm of a number to a specified base
LOG10- Returns the base-10 logarithm of a number
MDETERM- Returns the matrix determinant of an array
MINVERSE- Returns the matrix inverse of an array
MMULT- Returns the matrix product of two arrays
MOD- Returns the remainder from division
MROUND- Returns a number rounded to the desired multiple
MULTINOMIAL- Returns the multinomial of a set of numbers
ODD- Rounds a number up to the nearest odd integer
PI- Returns the value of pi
POWER- Returns the result of a number raised to a power
PRODUCT- Multiplies its arguments
QUOTIENT- Returns the integer portion of a division
RADIANS- Converts degrees to radians
RAND- Returns a random number between 0 and 1
RANDBETWEEN- Returns a random number between the numbers you specify
ROMAN- Converts an arabic numeral to roman, as text
ROUND- Rounds a number to a specified number of digits
ROUNDDOWN- Rounds a number down, toward zero
ROUNDUP- Rounds a number up, away from zero
SERIESSUM- Returns the sum of a power series based on the formula
SIGN- Returns the sign of a number
SIN- Returns the sine of the given angle
SINH- Returns the hyperbolic sine of a number
SQRT- Returns a positive square root
SQRTPI- Returns the square root of (number * pi)
SUBTOTAL- Returns a subtotal in a list or database
SUM- Adds its arguments
SUMIF- Adds the cells specified by a given criteria
SUMPRODUCT- Returns the sum of the products of corresponding array components
SUMSQ- Returns the sum of the squares of the arguments
SUMX2MY2- Returns the sum of the difference of squares of corresponding values in two arrays
SUMX2PY2- Returns the sum of the sum of squares of corresponding values in two arrays
SUMXMY2- Returns the sum of squares of differences of corresponding values in two arrays
TAN- Returns the tangent of a number
TANH- Returns the hyperbolic tangent of a number
TRUNC- Truncates a number to an integer

Statistical functions
Function Description
AVEDEV- Returns the average of the absolute deviations of data points from their mean
AVERAGE- Returns the average of its arguments
AVERAGEA- Returns the average of its arguments, including numbers, text, and logical values
BETADIST- Returns the beta cumulative distribution function
BETAINV- Returns the inverse of the cumulative distribution function for a specified beta distribution
BINOMDIST- Returns the individual term binomial distribution probability
CHIDIST- Returns the one-tailed probability of the chi-squared distribution
CHIINV- Returns the inverse of the one-tailed probability of the chi-squared distribution
CHITEST- Returns the test for independence
CONFIDENCE- Returns the confidence interval for a population mean
CORREL- Returns the correlation coefficient between two data sets
COUNT- Counts how many numbers are in the list of arguments
COUNTA- Counts how many values are in the list of arguments
COUNTBLANK- Counts the number of blank cells within a range
COUNTIF- Counts the number of nonblank cells within a range that meet the given criteria
COVAR- Returns covariance, the average of the products of paired deviations
CRITBINOM- Returns the smallest value for which the cumulative binomial distribution is less than or equal to a criterion value
DEVSQ- Returns the sum of squares of deviations
EXPONDIST- Returns the exponential distribution
FDIST- Returns the F probability distribution
FINV- Returns the inverse of the F probability distribution
FISHER- Returns the Fisher transformation
FISHERINV- Returns the inverse of the Fisher transformation
FORECAST- Returns a value along a linear trend
FREQUENCY- Returns a frequency distribution as a vertical array
FTEST- Returns the result of an F-test
GAMMADIST- Returns the gamma distribution
GAMMAINV- Returns the inverse of the gamma cumulative distribution
GAMMALN- Returns the natural logarithm of the gamma function, Γ(x)
GEOMEAN- Returns the geometric mean
GROWTH- Returns values along an exponential trend
HARMEAN- Returns the harmonic mean
HYPGEOMDIST- Returns the hypergeometric distribution
INTERCEPT- Returns the intercept of the linear regression line
KURT- Returns the kurtosis of a data set
LARGE- Returns the k-th largest value in a data set
LINEST- Returns the parameters of a linear trend
LOGEST- Returns the parameters of an exponential trend
LOGINV- Returns the inverse of the lognormal distribution
LOGNORMDIST- Returns the cumulative lognormal distribution
MAX- Returns the maximum value in a list of arguments
MAXA- Returns the maximum value in a list of arguments, including numbers, text, and logical values
MEDIAN- Returns the median of the given numbers
MIN- Returns the minimum value in a list of arguments
MINA- Returns the smallest value in a list of arguments, including numbers, text, and logical values
MODE- Returns the most common value in a data set
NEGBINOMDIST- Returns the negative binomial distribution
NORMDIST- Returns the normal cumulative distribution
NORMINV- Returns the inverse of the normal cumulative distribution
NORMSDIST- Returns the standard normal cumulative distribution
NORMSINV- Returns the inverse of the standard normal cumulative distribution
PEARSON- Returns the Pearson product moment correlation coefficient
PERCENTILE- Returns the k-th percentile of values in a range
PERCENTRANK- Returns the percentage rank of a value in a data set
PERMUT- Returns the number of permutations for a given number of objects
POISSON- Returns the Poisson distribution
PROB- Returns the probability that values in a range are between two limits
QUARTILE- Returns the quartile of a data set
RANK- Returns the rank of a number in a list of numbers
RSQ- Returns the square of the Pearson product moment correlation coefficient
SKEW- Returns the skewness of a distribution
SLOPE- Returns the slope of the linear regression line
SMALL- Returns the k-th smallest value in a data set
STANDARDIZE- Returns a normalized value
STDEV- Estimates standard deviation based on a sample
STDEVA- Estimates standard deviation based on a sample, including numbers, text, and logical values
STDEVP- Calculates standard deviation based on the entire population
STDEVPA- Calculates standard deviation based on the entire population, including numbers, text, and logical values
STEYX- Returns the standard error of the predicted y-value for each x in the regression
TDIST- Returns the Student’s t-distribution
TINV- Returns the inverse of the Student’s t-distribution
TREND- Returns values along a linear trend
TRIMMEAN- Returns the mean of the interior of a data set
TTEST- Returns the probability associated with a Student’s t-test
VAR- Estimates variance based on a sample
VARA- Estimates variance based on a sample, including numbers, text, and logical values
VARP- Calculates variance based on the entire population
VARPA- Calculates variance based on the entire population, including numbers, text, and logical values
WEIBULL Returns the Weibull distribution
ZTEST- Returns the one-tailed probability-value of a z-test

Text functions
REPLACE, REPLACEB
Function Description
ASC- Changes full-width (double-byte) English letters or katakana within a character string to half-width (single-byte) characters
BAHTTEXT- Converts a number to text, using the ß (baht) currency format
CHAR- Returns the character specified by the code number
CLEAN- Removes all nonprintable characters from text
CODE- Returns a numeric code for the first character in a text string
CONCATENATE- Joins several text items into one text item
DOLLAR- Converts a number to text, using the $ (dollar) currency format
EXACT- Checks to see if two text values are identical
FIND, FINDB- Finds one text value within another (case-sensitive)
FIXED- Formats a number as text with a fixed number of decimals
JIS- Changes half-width (single-byte) English letters or katakana within a character string to full-width (double-byte) characters
LEFT, LEFTB- Returns the leftmost characters from a text value
LEN, LENB- Returns the number of characters in a text string
LOWER Converts text to lowercase
MID, MIDB- Returns a specific number of characters from a text string starting at the position you specify
PHONETIC- Extracts the phonetic (furigana) characters from a text string
PROPER- Capitalizes the first letter in each word of a text value
Replaces characters within text
REPT- Repeats text a given number of times
RIGHT, RIGHTB- Returns the rightmost characters from a text value
SEARCH, SEARCHB- Finds one text value within another (not case-sensitive)
SUBSTITUTE- Substitutes new text for old text in a text string
T- Converts its arguments to text
TEXT- Formats a number and converts it to text
TRIM- Removes spaces from text
UPPER- Converts text to uppercase
VALUE- Converts a text argument to a number

External functions
Function Description
EUROCONVERT- Converts a number to euros, converts a number from euros to a euro member currency, or converts a number from one euro member currency to another by using the euro as an intermediary (triangulation)
SQL.REQUEST- Connects with an external data source and runs a query from a worksheet, then returns the result as an array without the need for macro programming

Computer Architecture

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Computer architecture can be defined as the arrangement or construction or design of different components of a computer. It defines how the different components of the computer are connected with each other.

Different components of the computer are given below:

Input unit
Memory unit
CPU
Output unit

1. Input unit
Input Unit is responsible for providing data and instructions to the CPU. It accepts input, converts it into computer’s format and provides it to system memory.
Keyboard is the most common input device. Some other input devices include mouse, joystick, light pen, touch screen, scanner, webcam, and microphone, touch pad and so forth.

2. Memory unit
Memory unit is responsible for storing data and instructions either for a short or longer period of time. Memory is of two types:

Primary Memory/Main memory
Secondary Memory/Auxiliary memory

- Primary memory
Primary memory is used for storing data and instructions during processing. It is the only memory which is directly accessible to CPU. It is expensive, faster and used in small capacity.
Examples:
· RAM
· ROM
· Cache memory

- Secondary memory
It is the additional memory used for storing huge amount of data for a longer period of time. It is also used for transferring data from one computer to another. It is usually cheaper, slower and used in larger capacity. It is not directly accessible to CPU.
Examples: CD, DVD, Hard disk, pen drive, etc.

3. CPU (Central processing unit)
CPU is responsible for processing the inputs for generating the outputs. It controls all the component of the computer. CPU contains three sub-components. They are:

ALU
CU
Set of Registers

- ALU (Arithmetic and logic unit)
It performs arithmetic and logical operations. It performs all its task according to the control signal from CU.

- CU (Control unit)
CU is responsible for controlling all the components of the computer including input devices, output devices, memory devices and other components of CPU. It uses control signal for controlling.

- Set of registers
Register is a temporary memory present in CPU. It is used for storing data instructions while it is being processed by CPU. CPU contains registers like MAR, MBR, TR, etc.

4. Output unit
Output unit is responsible for providing the result after processing. It converts the output from computer’s format into user understandable format before providing it to the user. The outputs generated by the computer are of two types:

Soft copy output
Hard copy output

- Soft copy output

The output from monitor, speaker, projector, etc. is termed as soft copy output. User cannot touch or feel this output. This output remains with the user till the computer is in ON state. User can modify the output is required.

- Hard copy output
The output from printer and plotter is termed as hard copy output. User can touch or feel this output. After the output is generated, it remains with the user even if the computer is in OFF state. User cannot modify the output.

SPOOL (Simultaneous Peripheral Operation On-line)

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

It is a free space of secondary memory managed by OS for the communication with peripheral devices like printer. It is required because of the difference in the operating speed of the CPU and peripheral devices. Peripheral devices are slow in their operation. The process of using SPOOL is known as spooling.

Operating system

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Operating system is an interface between computer and hardware and application software. Without OS no computer can be operated. Operating system is regarded as the heart of living being for a computer system.
In other words, OS is defined as a program or suit (support for) of programs that controls the entire operation of the computer, such as recognizing input from keyboard, sending output to the display screen keeping track of files and directories on the disk and controlling peripheral devices such as disk drives and printers.

Basic organization of operating system:

Buffer

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Buffer

It is a temporary memory located in different hardware devices mainly I/O devices. This memory is used to store data during I/O process. The process of using buffer for computer operation is known as buffering.

Computer Science HSEB-XI 2069

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Computer science (HSEB-grade XI)-2069 (2012)
Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.

Full Marks:- 75
Pass Marks:- 27
Time:- 3hrs.

Group ‘A’
Long answer questions
Attempt any three questions. 3×10=30
1. What is an operating system? Explain the functions of operating system.
2. What is memory in the computer system? Explain primary and secondary memory.
3. What is programming? Differentiate between compiler and interpreter.
4. What is Boolean algebra? Describe AND gate, OR gate, NOT gate and NAND gate symbol and Truth Table.

Group ‘B’
Short answer questions
Attempt any nine questions. 9×5=45
5. Why computer is known as versatile and diligent device? Explain.
6. What is mobile computing? Explain.
Or
Differentiate between analog and digital computer.
7. Convert (110111101)2 binary number into octal number.
8. What is BUS in terms of computer architecture? Explain.
9. Differentiate between Impact and Non-impact printers with examples.
10. What is internet? Write down the uses of internet.
Or
Explain the features of word processor.
11. What is web page? List the features of web page.
Or
Write down the advantages and disadvantages of DBMS. (Old)
12. What is CPU? Write down the functions of CPU.
13. Explain the types of programming errors with examples.
14. Subtract (1100)2 from (1111)2 using 1st and 2nd complement method.
15. Write short notes on:

Modem
Trackball

Classification Of Computer

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Classification of computer

1. On the basis of Purpose of Use

General Purpose Computer
Special Purpose Computer

2. On the basis of speed/size

Super Computer
Mainframe Computer
Mini Computer
Micro Computer: Portable micro computer and non-portable micro computer

3. On the basis of Working Principle

Analog Computer
Digital Computer
Hybrid Computer

4. On the basis of Brand

IBM Computer: IBM computer and IBM compartable
Apple Computer

5. On the basis of Model

XT Computer
AT Computer
PS/2 Computer

& Difference Between Digital and Analog Computer