Safety here means, a condition or a measure taken to protect computers from unlikely damage, risk, danger or burglary.

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:

• Fit strong metallic grills and locks on the doors, windows & roofs (in case the roofing is weak).
• Lock the doors, (i.e., keep the computers in a strong room, which should remain firmly locked when not in use).
• Avoid welcoming strangers into the computer room.
• Use of Personal Identification cards.
• Use of fingerprint identification.
• Install security alarms at strategic access points so as to alert the security personnel in case of a break in.
• Use of special voice recorders that would be able to analyse the voice of a trespasser & check against the database containing the voice patterns of valid users.
• Secure/protect the computers with Passwords to minimize chances of theft.

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:

• The room should have large & enough windows & doors
• Installing an air-conditioning system.
• Installing cooling fans.
• Avoid overcrowding of either machines or people in the room.

• ​Set up the computer laboratory in a location away from excessive dust.
• Remove your shoes (keep your shoes clean)before you enter the computer room to prevent dust.
• The computer room should be fitted with special curtains that would reduce entry of dust particles.
• The floor should be covered with Carpets in order to absorb dust, and also absorb the noise made by chairs.
• Cover the computer devices with Dust covers when not in use or when cleaning the computer room.

NB:  If the environment is dusty, the computers should be regularly serviced to get rid of harmful dust.
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.

​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.

• To eliminate low humidity, place humidifiers in the room, while high humidity can be controlled by installing dehumidifiers in the room.

​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.

• Always use the manufacturer’s shipping carton when transporting the devices.
• Do not place heavy objects on the computers.
• Protect the computer devices especially the Monitor & the disks from any electrostatic discharge.
• The computer devices should not be exposed to direct sunlight or warm objects.  This causes the internal components of the computer to get heated, and as a result, effects the computer’s solder-joints.
• Students should only perform operations on the computer that they are sure of and under supervision.  If in doubt, the student should ask to ensure that no damage is caused due to lack of proper knowledge.
• Computer equipment should be regularly checked and serviced.

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.

This is an electrostatic technology powered printer that uses  a laser beam of light to create characters on a piece of paper.

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: 

1. Keyboard/Keypad
2. Mouse
3. Trackball
4. Scanner
5. Digitizer
6. Whiteboard
7. Digital camera
8. Joy stick

The CPU-Central Processing Unit is a device made from a collection of integrated circuits. Its main functions are:

1. Manipulate numeric and logic data (A.L.U - Arithmetic & Logic Unit)
2. Coordinate processing activities (Control Unit)
3. Provide temporary storage (Registers, buffers and caches)

These are devices that provide temporary storage for task that are to and from processing. They include:

1. RAM - Random Access Memory
2. ROM - Read Only Memory
3. Logical Drives: These are hard disk partitions that behaves like a RAM once that memory in the RAM has been fully utilized.

These are devices that permanently store data in the computer or they are portable. They include:

1. Fixed Storage Devices
   1. Magnetic
      1. The Hard Disk
2. Portable Storage Devices
   1. Solid State Storage Devices
      
      1. Memory card 
      2. Flash Disk
   2. Magnetic storage devices
      1. Magnetic tapes
      2. Floppy disks
      3. Zip disks
      4. Magnetic tape
   3. optical storage devices
      1. Compact disks (CD)
      2. Digital Versatile Disks (DVD)

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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:

1. Hard Copy
   1. Printer
   2. Plotter
2. Soft Copy
   1. Screen/Monitor/VDU
   2. LED - Light Emitting Diode
   3. Sound Output (such as speakers)

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.

​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]

​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.
[Source: https://www.quora.com/What-is-the-use-of-transistors-in-a-circuit#]

​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]

​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):

• In this Technology, 1-100 Transistors were fabricated on a single chip. eg Gates , Flipflops.

Medium Scale Integration (MSI):

• Using this Technology, 100-1000 number of Transistors could be integrated on a single chip. eg 4 bit Microprocessors.

Large Scale Integration

• In this Technology, 1000-10000 Transistors could be integrated on a single chip. eg 8 bit Microprocessors, RAM, ROM

Very Large Scale Integration(VLSI):

• In this Technology, 10000-1 Million Transistors could be accommodated. Eg 16-32 bit Microprocessors.

Ultra Large Scale Integration(ULSI):

• In this Technology, 1 Million-10 Million Transistors could be accommodated. Eg Special Purpose Registers.

Giant Scale Integration (GSI):

• In this Technology more than 10 Million Transistors could be accommodated. Eg Embedded Systems.

[Source: https://www.quora.com/What-is-VLSI/answer/Abhinav-Verma-137]

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.

1. Hardware Configuration i.e. speed, capacity, memory etc.
2. Make, size and nature of the computer i.e. laptop, desktop, phone, super computer, calculator etc.
3. Application intended for the computer. i.e. if the computer is a special purpose or general purpose
4. User friendliness i.e. capable for support Graphical User Interfaces (G.U.I)
5. Documentation such as warranty that spells terms of trade, receipt/invoices, user's manual etc.
6. The initial cost and maintenance cost.
7. Reliability and security.
8. Number of processors and hardware available
9. Number of users
10. Upgradeability 

​  A distributed system is a collection of computers on the same network which process data independently and once data has been updated in one computer, other computers of the same system automatically update their database too.
   A distributed system can also be defined as a collection of independent computers that appears to its users as a single coherent system
  Distributed processing refers to the type of processing where computers in various geographical locations are interconnected via communication links for the purpose of local processing and data access and/or transfer.
  In distributed processing data processing occurs on each of the computers, unlike a centralized processing system in which terminals are connected to a host computer that performs all of the data processing.

• Quicker response time
• Improved data integrity
• Resource sharing
• Parallel processing due to many processors leads to increased performance, reliability and fault tolerance

• Network failure paralyses operations
• Vulnerable to security threats
• Difficult to configure

• Kangasharju, J. (2008). Chapter 1: Distributed Systems. Retrieved 2019, from cs.helsinki: https://www.cs.helsinki.fi/u/jakangas/Teaching/DistSys/DistSys-08f-1.pdf
• technopedia. (n.d.). Distributed System. Retrieved 2019, from Technopedia: https://www.techopedia.com/definition/18909/distributed-system

​Normalization is the process of organizing data in a database by establishing relationships between tables according to rules designed both to protect the data and to make the database more flexible by eliminating redundancy and inconsistent dependency, insertion anomaly, update anomaly & deletion anomaly. 

1. ​Eliminate redundant data: redundancy is storing the same data in more than one table. This leads to unnecessarily duplication of data that could eventually require a lot of storage space. At the same time the user may not be able to efficiently update data.
2. Ensure data dependencies make sense by ensuring only related data is stored in a table. This happens when determining data relationships in a table.
3. It makes database structure flexible i.e. it should be possible to add new data values and rows without reorganizing the database structure.
4. It ensures data consistent throughout the database i.e. it should not suffer from the following anomalies.
   1. Insert Anomaly - Due to lack of data i.e., all the data available for insertion such that null values in keys should be avoided. This kind of anomaly can seriously damage a database
   2. Update Anomaly - It is due to data redundancy i.e. multiple occurrences of same values in a column. This can lead to inefficiency.
   3. Deletion Anomaly - It leads to loss of data for rows that are not stored else where. It could result in loss of vital data.
5. Easier to maintain data structure i.e. it is easy to perform operations and complex queries can be easily handled.

​Works Cited:

• Depaul.edu. (n.d.). Normalization. Retrieved 2019, from Depaul: http://condor.depaul.edu/gandrus/240IT/accesspages/normalization3.htm
• THAKUR, D. (2019). Database Normalization. Retrieved from eComputer Notes: http://ecomputernotes.com/fundamental/what-is-a-database/what-is-a-database-normalization
• UNDER, C. S. (2015, 11 17). Normalization in DBMS: 1NF, 2NF, 3NF and BCNF in Database. Retrieved 2019, from Bigginers' Book: https://beginnersbook.com/2015/05/normalization-in-dbms/