1. worksheet
2. database
3. graphs

• Getting started
• Worksheet layout
• Running the program

• editing a cell entity
• saving
• retrieving
• closing a worksheet exiting from spreadsheet

• Cell addressing
• Absolute referencing
• Relative referencing

• Functions
  i) statistical (average, count, max, mm)
  ii) logical (If, count-if, sum-it)
  iii) mathematical (Sum, Product, Div)
  

• Arithmetic formulae (using operators +, -, /,*, brackets)

• Text
• Numbers
• Rows and columns
• Global

• Types
• Data ranges
• Labels
• Headings and titles
• Legends

1. Has a large worksheet for data entry & manipulation as compared to manual worksheet.
2. Has inbuilt formulae called Functions that are non-existent in manual worksheets.  These functions enable the user to quickly manipulate mathematical data.
3. Uses the power of the computer to quickly carry out operations.
4. Has better formatting & editing qualities than the manual worksheet.
5. Utilizes the large storage space available on computer storage devices to save & retrieve documents.
6. Can easily be modified in its form, while a manual spreadsheet involves a lot of manual calculations & are very difficult to amend.
7. The user can very quickly & efficiently perform complicated computations using the information stored in an electronic spreadsheet.
8. It is accurate in its calculations & allows automatic recalculation on formulae.
   I.e., when one value/figure is changed, the result of the formula is automatically adjusted by the computer so as to correspond with the different input.  For a manual spreadsheet, changing one value means rubbing the result & writing the correct one again.
9. It offers graphical representation of data leading to comprehensive decisions.
10. Replaces the pencil & paper approach of the manual operations of the worksheet.
    I.e., it enables the user to produce neat work because; all the work is edited on the screen and a final copy is printed.  With a manual spreadsheet, neatness & legibility of the work depends on the writer’s hand-writing skills.
11. It improves on the capabilities & speed of the Calculator.

1. VisiCalc – this was the 1st type of spreadsheet to be developed for PCs.
2. Lotus 123 – this is an integrated software with spreadsheet module, graphs, and database.
3. Microsoft Excel.
4. Corel Quattro-Pro
5. Microsoft Works Excel
6. Super calculators.
7. Multiplan.
8. Vp-Planner.

1. Define a Spreadsheet.
2. Differentiate between the traditional analysis ledger sheet and an electronic spreadsheet.
3. Name three commonly spreadsheet packages.

1. Workbook.
2. Database.
3. Graphs / Charts.

1. Name and describe the three components of a spreadsheet.
2. Explain the following terms as used in spreadsheets.
   i)    Workbook.
   ii)    Chart.

• Record sales & purchases.
• Calculate profits.
• Produce Invoices, and also compile financial statements.
• Prepare budgets.
• Assist the management of an organization to monitor the current state of payments from customers in relation to goods delivered.
• Detect aged debtors (i.e., those people who have owed you money for more than the period allowed in your terms of business.
• Track the value of assets over time (i.e., Appreciation and Depreciation).

• It enables the user to create, edit, save, retrieve and print worksheet data & records.
• It enables data to be arranged neatly in tabular structure.
• Related data can be typed on the same worksheet.  If the data is on different worksheets, the worksheets can be linked so that the data can be accessed easily.

• Sorting (i.e., arranging worksheet records in a particular order so as to easily access the data items).
• Filtering (i.e., displaying only the records that meet a given condition).
• Use of Forms to enter & view records.
• Use of Total/Subtotal function.

• AVERAGE – used to calculate the mean of a set of values.
• MEDIAN – used to give the value in the middle of a set of values.

• Teachers to compile their students’ marks and produce results.  
• Clerks & Secretaries to enable them easily create tables of figures and manipulate them quickly as required.

1. Explain five application areas where spreadsheet software can be used.
2. Explain the concept of “What if” analysis.

1. Have the ability to create, edit, save & retrieve worksheets.
2. Have inbuilt functions & formulae which can be used to perform calculations.
3. Allows Automatic recalculation, i.e., when you change one value, the rest of the values in the spreadsheet are automatically recalculated by the computer to correspond with the different input.  This enables you to play “what if” games with your system.
4. Have the ability to Sort and filter data (i.e., arrange data in a predefined order).
5. Have a Data validation facility, which ensures that the correct data is entered into the Spreadsheet.
6. Have a Chart facility that can be used to draw line graphs, Bar charts, histograms, etc.
7. Have the ability to format data (both text & numeric data) using predefined formats.
8. Some Spreadsheets have a SOLVER facility that is used to uncover the best uses of scarce resources so that desired goals can be achieved.
9. Have the ability to adjust Column widths & Row heights automatically.
10. Have the ability to hide and unhide rows & columns, and also freeze panes.
11. They enable printing of worksheets within the shortest time possible.
12. They have pre-designed Templates for automating tasks.  
    A Template is a document that acts as a blueprint or outline for other documents of the same type.  It contains the standard text, graphics & formatting that will be used in all documents of this type.
    This means that, all formulas and formatting for similar workbooks such as Invoices can be saved as templates and then be used to automate the task without having to create the workbook again.
13. Have the ability to summarize data using Consolidation and Pivot tables.  
    Consolidation allows the merging of several worksheets into a summary sheet, while still keeping the original worksheets intact.  Consolidation adds together cells with the same co-ordinates in the various worksheets.
    Pivot tables can be used to cross-tabulate large amounts of data. 
    Differences between an Electronic Spreadsheet and a Calculator
    

1. Has more memory than calculator.
2. Is able to perform complex logical operations, but a calculator cannot.
3. Uses the large storage capacity of the computer that a calculator does not have.
4. Has a large working area that a calculator does not have.

1. Describe any five features of a spreadsheet program.
2. State five features of spreadsheets that are useful in financial modelling.
3. How does a spreadsheet differ from a Calculator

1. Data is kept in one location, ensuring that every user is working with the same information.
2. It is easier to back up data since the information is stored on only one Server.
3. Easier to maintain security.  It is only the server which needs to be secured since the terminals have no data.
4. The terminals do not require floppy drives as all work is stored on a Server.
5. Chances of computer being affected by viruses are very minimal as no diskettes are being used.
6. It less costly.

1. It is very slow as it is the server alone, which does all the processing.
2. In case where the users have varied needs, it would be difficult to meet these needs in a centralized computing network as each user application needs to be set up separately.
3. Connection is difficult.  All the computers have to be connected on a central place.

1. Each machine processes and stores its data; hence, data is accessed faster.
2. It doesn’t need powerful and expensive servers for data storage.
3. It can accommodate users with variety of needs.

1. It is more susceptible to virus, as any user could introduce an infected file and spread it throughout the network.
2. It is more difficult to develop an effective back up plan, since each user stores data in his/her individual system.
3. File management (organization) is difficult as the files are stored in different locations.

1. It is faster to complete a task as users are not limited to processing power of one system.
2. Variety of users can be accommodated on a collaborative network.

1. Viruses can easily be transmitted through the network.
2. Backing up of the data is difficult.
3. File synchronization is difficult.

• There are 10 or less users.
• The users are located in a general area.
• Security is not an issue, e.g. in Bulletin boards.

1. It is small & inexpensive.
2. It is easier to maintain.
3. It is easier to setup.

1. It is difficult to locate information stored in the connected computers due to Shared level security.
2. Difficult to update documents and files.
3. It is expensive to train staff on how to share resources, as each user is an administrator.
4. It is difficult to maintain security, as it is the user’s responsibility to ensure that only authorized individuals can access their data.
5. It is more tedious as the user has to memorize password for resources, and in case of any change, they have to inform others.

1. There is security since the Server controls the resources the clients need to access.
2. It can support a large number of users.
3. The server can be optimized to hand out information as fast as possible.
4. Fewer connections are required by the clients to get the resources.
5. Easier to maintain backup for files (synchronization of files).
6. Cost effective as client workstations don’t need large hard disk (storage capacity).

1. It is dependent on a Network administrator.
2. Requires servers, which are expensive.

1. Centralized computing.
2. Collaborative computing.
3. Distributed computing.

1. As regards to communication within a computer network, what do you understand by the following terms:
   (a)    Point-to-point
   (b)    Broadcast            

1. Point-to-point communication.
2. Broadcast communication.

1. What is a computer network topology?
2. Distinguish between Logical and Physical network topology.
3. Using appropriate diagrams, describe any three types of physical network topologies.

1. Ethernet.
2. Token ring.

1. Star topology.
2. Bus topology.
3. Ring topology.
4. Mesh topology.
5. Tree (Hierarchical) topology.

1. Allows key networking resources such as concentrators & servers to be centralized.
2. Easy to configure.
3. Enhances operational survivability.
   The hub isolates the network cables from each other.  Even if a wire between a workstation and the hub breaks or develops a bad connection, the rest of the network remains operational.
4. Simple to control.
5. It can be extended easily, since a workstation is simply connected to the hub.
6. Provides flexibility in adding or deleting devices.
   The wiring hubs increase the flexibility for growth.  Addition & removal of nodes does not involve cutting and joining of cables.
7. Easier to troubleshoot.
   When something goes wrong with the network, the administrator can troubleshoot it from the wiring hub.
8. The Hub can support multiple types of cables.

1. If the central switch node (Hub) fails, it may bring down the entire network.
2. It is costly because; each workstation is connected to the central concentrator by is own dedicated cable (i.e., it requires a lot of cables).
3. Installation is time consuming, because each node forms a segment of its own.
4. May require a special device for signal regeneration across the network.

1. Easy to install.
2. Inexpensive (less costly) because; it does not require a complete cable length per computer.
3. Can easily be extended.
4. It allows the workstations to communicate independently (separately) of each other.
5. Failure of one station on the network does not affect the operations on the bus.

1. They use a short length cable.
2. Simple to install.
3. Provides high performance for many users.
4. Provides an orderly network in which every device has access to the token and can transmit data.

1. Failure of one computer or the cable will affect the rest in the entire network.
2. Modification is difficult because; adding or removing a device can disrupt the entire network.
3. Troubleshooting can be difficult.

1. It is fast.
2. Failure on one node will not cause communication breakdown.
3. Easy to troubleshoot cable problems.  If two machines are not communicating, the administrator will only check the cable between them.
4. Enhances flexibility in communication.
5. Enhances fault tolerance provided by redundant/ excessive links.

1. Difficult and expensive to install and maintain.
2. Very costly as it requires large amounts of cables (or redundant links).
3. Difficult to add more nodes when the network is large.
4. Difficult to isolate faults due to lack of a central control point.

1. List two types of network software.
2. Outline four functions of network operating system.
3. List four examples of network operating systems.
4. Outline the seven open systems interconnection (OSI) reference model layers.
5. Explain the importance of the Physical layer in the open systems interconnection (OSI) reference model.
6. (a). Define the term protocol.
   (b). Give three examples of protocols used in networking.

1. Network Operating systems.
2. Network Protocols.

1. Provides access to network resources, e.g., printers and folders.
2. Enables nodes on the network to communicate efficiently with each other.
3. Enables the various processes on the network to communicate with one another.
4. Responds to requests from application programs running on the network.
5. Supports network services such as network card drivers & protocols.
6. Maintains security, ensuring that only users authorized to use the computer system are allowed access to it.
7. Produces logs, i.e., a record of all the programs as they are run.
8. Organises the use of storage, since this has to be shared among different users.
9. Works out the resources used by each program.  If the user is paying for the service, then the computer works out the cost of running the program & charges the appropriate account.

• UNIX                    - Windows NT
• Linux                    - Windows 2000
• Novell NetWare        - Windows 2003

• The data transmission process over the network is divided into steps, and at each step, a certain action takes place.
• In addition, each step has its own rules and procedures as defined by the network protocols.  The work of these protocols is usually coordinated through protocol layering so as to ensure that there are no conflicts or incomplete operations.

1. Simple Mail Transfer Protocol (SMTP) - an Internet protocol for transferring e-mails.
2. File Transfer Protocol (FTP) – an Internet protocol for transferring files.
3. Apple Talk and Apple Share – a networking protocol standard for Apple computers.

1. Transmission Control Protocol (TCP) – enables delivery of sequenced data over the network.
2. Sequential Packet Exchange (SPX) – used in Novell networks for sequenced data.
3. NetBEUI – used in Microsoft and IBM networks to establish communication sessions between computers in LANs.
4. Apple Transaction Protocol (ATP) – it is a communication session and data transport protocol used in Apple computers.

1. Internet Protocol (IP) – it does packet forwarding and routing.
2. Internetwork Packets Exchange – This is a NetWare’s protocol for packet forwarding and routing.

1. Describe at least five devices used in data communications.
2. Explain the function of a NIC in networking.
3. (a). Explain the importance of a gateway on a network.
   (b). Differentiate between a router and a gateway.
4. Why is a Switch preferred to a hub on the network?
5. What is the function of a Repeater on a network?
6. Give one disadvantage of a Hub on a network.

1.    Access points (AP)

1.    Network Interface cards (NIC)

• Intelligent hubs also manage a network by isolating computers that are not functioning properly.

1. It can divide a busy network into segments to reduce network traffic.
2. To extend the length & number of workstations that a segment can support.
3. To reduce overall traffic flow by allowing broadcasts only in the destination segment of the network.

• Switches are more expensive than hubs.  This means that, one switch may be used as a bridge to connect several hubs.  This reduces collision problems caused by broadcasts.

1. Distinguish between radio and microwave transmission.
2. Describe an electromagnetic spectrum.
3. State two advantages of satellite communication.
4. Give one application area of Infrared transmission.
5. Describe the VSAT technology.
6. Explain the concept of a geostationary satellite.
7. Explain the line of sight principle in wireless communication.

1. Microwaves.
2. Radiowaves.
3. Infrared transmission.

1. Transmitter earth station - it sets up an uplink to the satellite in order to transmit data.
2. A Satellite that is somewhere in an orbit.  It receives, amplifies, and retransmits the signal to a receiving earth station through a downlink frequency. The downlink & the uplink frequency are usually different.  This is to prevent the downlink signal from interfering with the uplink signal.
3. Receiving earth station - receives the signal sent by the satellite on the other side of the globe.

1. A satellite is convenient because; it provides a large constant line of sight to earth stations.  This means that, there is no need to keep on moving the parabolic dish so as to track the line of sight.
2. The satellite transmits the signal to many recipient earth stations.  This is because; the transmitted signal spreads out in all directions to form a Point to Multipoint transmission.

• High frequency (HF).
• Very high frequency (VHF).
• Ultra-high frequency (UHF).

• The signal can be intercepted by unauthorized parties.

• Very High frequency (VHF) radio waves

1. Wireless medium is flexible in operation, i.e., devices can be moved around without losing access to the network.
2. Wireless networks can span large geographical areas easily.
3. Wireless communication can take place via satellite even in very remote areas that do not have high cost physical infrastructure like telephone lines.

1. The initial cost is very high.
2. It is relatively difficult to establish or configure.

1. Define the term Transmission media.
2. (a). Give two advantages of coaxial cables.
   (b). Explain the importance of the wire braid in coaxial cable.
3. Distinguish between Thinnet and Thicknet coaxial cables.
4. Define the term Pitch as used in twisted pair cabling.
5. (a). Give two advantages of fibre optic media.
   (b). Differentiate between single mode and multimode fibre optic cables.

• It is the outer covering of the cable.
• Light transmission along a fibre optic cable.
• The light signal travels along the core through a process referred to as Total internal reflection.  
• The process that causes total internal reflection is called Refraction.  Refraction is the bending of light when it crosses the boundary of two mediums that have different densities.
• Therefore, when light signal is inserted into the cable, it tries to cross from the core to the cladding.  The light is bent back into the core, hence spreads along the length of the cable.

• It has a very low attenuation rate, and is preferred for long distance transmission.
• It has a very high bandwidth of 50 Gigabits per second.
• It is very expensive, and requires very careful handling during installation.

• It allows several light signals (rays) to be sent through the cable at the same time.  Hence, there are high chances of the signal being distorted.
• It has a high attenuation rate, and is usually used for shorter distance transmission.

1. It is immune to electromagnetic interference, and eavesdropping.
2. It is fast and supports high bandwidth.
3. It has low attenuation; hence, a long distance can be covered.
4. It does not generate electrical signals; hence can be used in dangerous (highly flammable) places.
5. It is smaller & lighter than copper cables; hence, suitable for situations where space is limited.

1. Requires expensive connectivity devices and media.
2. Installation is difficult because the cable must be handled carefully.
3. It is relatively complex to configure.
4. A broken fibre optic cable is difficult & expensive to repair.

1. Data communication media.
2. Communication devices.
3. Networking software.

1. Two-wire open lines cables.
2. Twisted pair cables.
3. Coaxial cables.
4. Fibre optic cables.

1. Unshielded twisted pair (UTP).
2. Shielded twisted pair (STP).

1. They suffer from high attenuation.  Therefore, for every cable length of 90m, a “Repeater” is needed to amplify (restore) the signal.
2. It is sensitive to electromagnetic interference & eavesdropping.
3. It has low data transmission rates as compared to other cables.

• A central copper core (which is either solid or stranded wires).  The diameter of the centre core determines the attenuation rate. If the core is thin, then the attenuation rate will be higher.

• An insulator (a dielectric material) surrounding the copper core.
• A hollow braid (mesh conductor) surrounding the insulator.  The braid is made of copper or aluminium, and serves as the ground for the carrier wire.
• A shield which covers the braid making the core more resistant to electromagnetic interference.

1. They are very stable even under high loads.
2. They have a large bandwidth (up to 1Gbps) compared to twisted pair cables.
3. They can carry voice, data and video signals simultaneously.
4. They are more resistant to radio and electromagnetic interference than twisted pair cables.

1. Thick coaxial cable is hard to work with.
2. They are relatively expensive to buy & install compared to twisted pair cables.

1. Local Area Network (LAN).
2. Metropolitan Area Network (MAN).
3. Wide Area Network (WAN).

1. They enable many users to share expensive devices such as Laser printers, as well as data.  However, the no. of computers that can be connected & the distance to be covered is limited.
2. Have Low cost (requires less expensive equipment).
3. Enable users to communicate with each other, by sending messages or engaging in chat sessions.
4. LANs transmit data at very fast rates.  They are much faster than data transmitted over telephone lines.
5. Small error counts (low error rates).

• Larger than LAN.
• Slower than LAN, but faster than WAN with data rates of 100MBps & above.
• Are more expensive than LANs, since special equipment is needed to connect the different networks together.
• Prone to few errors (moderate error rates).

1. They cover an unlimited (a very large) geographical area, e.g., can cover the whole world.
2. They are expensive to build since it requires special equipment for connection.
3. Their transmission links are also expensive.
4. Long distance transmission.
5. Have low data transfer rates compared to LANs (i.e., they are slower than LANs & MANs)
6. More prone to errors (very high possible error rates compared to LANs and MANs).

1. LAN is limited to a small geographical distance.
2. Data transmission speed in LANs is higher.
3. Cost of data transmission in LANs is small.
4. There are less transmission errors in LANs.

1. List four network systems that are not computer-based networks.
2. Define the following terms:
   (a).    Computer network.
   (b).    Data communication.
3. Differentiate between:
   (a).    A baseband and broadband signal.
   (b).    A Network server and a workstation.
   (c).    Remote client and remote host.
   (d).    Half duplex and full duplex transmissions.
4. State the factors to be considered while selecting a data transmission system.
5. Give four advantages and two disadvantages of networking.
   (a)    Explain the concept of distributed processing in networking.
   (b)    State 3 advantages and 2 disadvantages of distributing processing.
6. Why is a network more reliable than stand alone computers?
7. What do you understand by the following terms in networking:
   
   

   ---

   ---

   (i).    Baud.
   (ii).    Baud rate.
   (iii).    Bandwidth.
   (iv).    Resource.
8. What name do we give to each of the following:
   (a).    The computer that is dedicated to serving requests from other computers in a network.
   (b).    The computers that sends requests.