|ANALYSIS OF KCSE COMPUTER STUDIES QUESTIONS & REVISION KITS|
|ANALYSIS OF KCSE COMPUTER STUDIES QUESTIONS & REVISION KITS|
DEFINE THE FOLLOWING TERMS; 1)FILE; 2) RECORD; 3) FIELD
A file, record and a field are database terms used especially when dealing with tables.
What is a file
A file is a collection of records, database files organize the data into records and fields.
Further definition of a file;
What is a record?
A record is a collection of related fields that represent a single entity
What is a field?
A field is a character or a logical combination of characters that represent a single data item.
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GIVE TWO TYPES OF STORAGE DEVICES USED IN A COMPUTER GIVING AN EXAMPLE OF EACH.
There are various categories under which storage devices can be classified;
a) CLASSIFICATION OF STORAGE DEVICES BASED ON THE DURATION OF TIME THEY STORE INFORMATION.
Storage devices in this category can either be;
b) classification of storage devices based on mobility.
Storage devices can also be categorized according to mobility. I.e.
c) classification of storage device on how they function.
Storage devices functions in different ways depending on the technology used to manufacture each one of them. They include;
give any three precautionary measures considered to ensure the safety of computers in a computer laboratory
tHE KEYWORD HERE IS 'SAFETY'
Safety here means, a condition or a measure taken to protect computers from unlikely damage, risk, danger or burglary.
POSSIBLE PRECAUTIONARY MEASURES
1. BURGLAR PROOFING
Physical access to the computer room should be restricted to ensure that only authorized persons get access to the computers.
To prevent unauthorized access to the computer room, the following controls should be implemented:
Both computers and human beings emit heat energy into the environment. Therefore, the computer room must have good circulation of air to avoid overheating and suffocation.
Proper ventilation enables the computers to cool, and therefore, avoids damaging the electronic parts.
The following facilities can ensure proper ventilation in a room:
3. DUST CONTROL
The service should include; blowing dust from the System unit, cleaning the floppy drives, cleaning the Keyboard, cleaning the Monitor externally, and also cleaning all peripheral devices such as Printers and Mouse.
4. DUMP CONTROL.
Humidity in the computer laboratory must be regulated to remain at an optimum 50%. If the humidity is low, it allows static electricity to build up and causes damage to sensitive electronic components. Similarly, high humidity of over 70% causes rusting of the metallic parts of the computer system.
5. HANDLING OF MATERIALS & EQUIPMENT.
Computer devices must be handled with a lot of care as they are extremely fragile and can easily get damaged. Dropping or bumping can cause permanent damage on the device, e.g., to transport the System unit always handle it on its frame.
previously: A SPREADSHEET HAS THE FOLLOWING ENTRIES. PROVIDE A FORMULA FOR CELL C5 THAT CAN BE COPIED ONTO CELL D5 AND THE RANGE C6...D10 TO GIVE A UNIFORM INCREASE OF 10% OF THE PREVIOUS YEARS VALUE FOR EACH ITEM.
This is the ability for a computer to accept data either through input devices such as scanners, keyboards, mice and others or through information retrieved from storage devices.
Input of data is a main function because all other functions depend on the incoming data for processing and output.
Processing and storage are sometimes broken down as separate basic functions of a computer. However, looking at this critical idea keenly, we notice that processing and storage are sometimes inseparable this is because processing devices rely heavily on storage devices vis a vis.
Processing is an act where a computer converts raw meaningless piece of information called data into a more meaningful piece of information.
This is normally done with a closer help of primary storage devices such as the RAM, and special types of memories such as the registers, buffers and cache memory.
Processing is a main function of a computer because of the conversion, manipulation of numeric data and logical decisions.
This is an act for a computer to display the result of a processing activity. This can be done using output devices such as the monitor, printer, plotter, speakers etc.
The functions of a computer system cannot be complete without the output, simply because it gives a feedback of the result for the computer user to digest, change, amend, store or print.
next: GIVE ANY THREE PRECAUTIONARY MEASURES CONSIDERED TO ENSURE THE SAFETY OF COMPUTERS IN A COMPUTER LABORATORY
A spreadsheet has the following entries. Provide a formula for cell c5 that can be copied onto cell d5 and the range c6...d10 to give a uniform increase of 10% of the previous years value for each item.
A spreadsheet has the following entries.
Provide a formula for cell c5 that can be copied onto cell d5 and the range c6...d10 to give a uniform increase of 10% of the previous years value for each item.
What is a laser printer?
This is an electrostatic technology powered printer that uses a laser beam of light to create characters on a piece of paper.
How a laser printer works
RELATED LINKS ..
Advantages of laser printers
Disadvantages of laser printers
wHAT ARE SECONDARY sTORAGE DEVICES?
Also called auxiliary storage devices or persistent storage media are computer hardware devices involved in the storage of data, permanently.
These devices can be categorized as:
Related links ..
01. INPUT DECICES
These are devices that enter data into a computer and also covert data from human readable form to machine readable form.
Examples of these devices include:
02. Central Processing unit
The CPU-Central Processing Unit is a device made from a collection of integrated circuits. Its main functions are:
03. Primary Storage
These are devices that provide temporary storage for task that are to and from processing. They include:
04. Secondary Storage
These are devices that permanently store data in the computer or they are portable. They include:
05. Output Devices
These are devices that display activities in the CPU to the user and converts information from machine readable form to human readable form. These devices include:
In the evolution of computers, each of the passing computer generations had its own technology which was an improvement of the previous technology. Below is a match of computer generations with their processor technology and what each of the processors were capable of.
01. FIRST GENERATION COMPUTERS
They used thermionic valves
This is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. as a thermionic tube or thermionic valve uses the phenomenon of thermionic emission of electrons from a heated cathode and is used for a number of fundamental electronic functions such as signal amplification and current rectification. [Source: https://en.wikipedia.org/wiki/Vacuum_tube]
02. SECOND GENERATION COMPUTERS
They used transistors
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit.
How does a transistor work ?
By turning a small input current into a large output current, the transistor acts like an amplifier. But it also acts like a switch at the same time. When there is no current to the base, little or no current flows between the collector and the emitter. Turn on the base current and a big current flows.
03. THIRD GENERATION COMPUTERS
They used Integrated Circuits (ICs)
A collection of transistors make up an Integrated Circuit
An integrated circuit (IC), sometimes called a chip or microchip, is a semiconductor wafer on which thousands or millions of tiny resistors, capacitors, and transistors are fabricated. An IC can function as an amplifier, oscillator, timer, counter, computer memory, or microprocessor. A particular IC is categorized as either linear (analog) or digital, depending on its intended application. [Source: https://whatis.techtarget.com/definition/integrated-circuit-IC]
04. FOURTH GENERATION COMPUTERS
They used very large scale integrated (VLSI)
VLSI is an acronym that represents Very Large Scale Integrated.
A collection of Integrated Circuits (ICs) Make up VLSI
An Integrated Circuit is the circuit in which all the Passive and Active components are fabricated onto a single chip. Initially the Integrated Chip could accommodate only a few components. As the days passed, the devices became more complex and required more number of circuits which made the devices look bulky. Instead of accommodating more circuits in the system, an Integration technology was developed to increase the number of components that are to be placed on a single chip. This Technology not only helped to reduce the size of the devices but also improved their speed. Depending upon the number of components (Transistors) to be integrated, they were categorized as SSI, MSI, LSI, VLSI, ULSI & GSI.
Small Scale Integration (SSI):
What is an operating system
An operating system is a collection of integrated computer programs that provide recurring services to other programs or to the user of a computer.
These services consist of disk and file management, input/output activities, storage resources, diverse support services and control of various resources.
Ssmengg.edu.in describes an operating system as a program that acts as an intermediary between a user of a computer and the computer hardware. it further adds "the purpose of an operating system is to provide an environment in which a user can execute programs and the primary goal of an operating system is thus to make the computer system convenient to use."
Tutorial point describes an Operating System (OS) as an interface between a computer user and computer hardware. An operating system is a software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers.
Some popular Operating Systems include Linux Operating System, Windows Operating System, VMS, OS/400, AIX, z/OS, etc.
factors to consider when choosing an operating system
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