COMPUTER ETHICS AND SECURITY

Hye! Today I will share about Computer ethics and  Security. But first, do you know what is Computer ethics and Security? Have you ever heard about Computer ethics Security? 'No'? Or maybe 'yes' but don't know what does it actual mean? Okay, don't worry! Let me introduce you to Computer ethics and Security.

chapter 4 : computer ethics and  security

4.1 COMPUTER ETHICS 

       what is computer ethics?

Computer Ethics are the moral guidelines that oversee the use of computers and information systems

4.1.1 netiquette 

what is nettique 

•      Netiquette, (short for Internet etiquette), is the code of acceptable behaviors users should follow while on the Internet.

                        OR

•      Netiquette is the code of acceptable Internet behavior.

Netiquette includes rules for all aspects of the Internet services, including:

• The World Wide Web
• E-mail
• Instant messaging
• Chat rooms
• Newsgroups and message boards.
• Social Media
• FTP

4.1.2 area of computer ethics 

Information Accuracy is a measure of the reliability of information held within an IT system

Green Computing involves reducing the electricity and environmental waste while using  computers.

Codes of Conduct is a written guideline that helps determine whether a specific computer action is ethical or unethical.

Intellectual property (IP) refers to unique and original works such as logos, brands, ideas, inventions, art, writings, process, company and product names.

Information Privacy refers to the right of individuals and companies to deny or restrict the collection and use of information about them.

COMPUTER SECURITY

what is computer security?

A computer security risk is any action that could cause a loss of or damage to computer hardware, software, data, information, or processing capability.

types of security risks 

1.         Malware / Malicious Code

Information transmitted over networks has a higher degree of security risk than information kept on an organization’s premises

Internet and network attacks that are exposed to security include :

     (a) Malware / Malicious Code

     Malware is malicious software, which are programs that act without a user’s knowledge and deliberately /purposely  alter the computer’s operations.

Types of Malware :

*Computer viruses

*Worms

*Trojan Horses

SYMPTOMS OF MALWARE/ MALICIOUS CODE 

TYPES OF MALWARE

•Computer Viruses

A potentially damaging program that affects, or infects a computer or mobile device negatively by altering the way the computer or device works without the user's knowledge or permission.

Once the virus infects the computer, it can spread throughout and may damage files and system software, including the operating system.

•Worms

A program that copies itself repeatedly, for example in memory, using up resources and possibly shutting down the computer, device or network.

•Trojan Horse

A program that hides within or looks like a legitimate program.  Unlike a virus or worm, a trojan horse does not replicate itself to other computers or device.

It usually appears to be a game or utility program.

Cannot replicate themselves; must be downloaded and installed.

*images above is one of the lab activities science computer which is produce bulletin

okay just this for today.. so.. lets protect our computer ^_^ 

HARDWARE

last posted, i explained about motherboard. now i would to share about PROCESSOR.


PROCESSOR

the processor interprests and carries out the basic instructions that operate a computer.

components of processor

- control unit (CU)
  directs and coordinatesmost of the operations in the computer.
   *it interprest each instruction issued by a program and then initiates the appropriate action to carry out the instruction

- arithmetic logic unit (ALU)
  performs arithmetic operations [+,-,x,and /] and performs logical operations such as comparing two pieces of data to see if they are equal or determine if a specific condition is true or false.


manufacturer of processor

• most processor chip manufacturers now offer multi core processor.
• multi processor: is a single chip with two or more separate processor cores.
• the leading manufacture of personal computer processor chips are Intel and AMD 

The Machine cycle of a Processor 
       - for every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle.

so, this all about processor (for our syllabus). hope this could help you to make a notes.

HARDWARE

what is hardware?

In information technology, hardware is the physical aspect of computers, telecommunications, and other devices. The term arose as a way to distinguish the "box" and the electronic circuitry and components of a computer from the program you put in it to make it do things. The program came to be known as the software. it's also Refers to objects that you can actually touch, like disks, disk drives, display screens, keyboards, printers, boards, and chips. In contrast, software is untouchable. Software exists as ideas, concepts, and symbols, but it has no substance.

SYSTEM UNIT

 the sistem unit or chassis is a case that contains and protects the motherboard, hard drive, memory and other electronic components. 

MOTHERBOARD?

yes motherboard. motherboard is the main circuit board of the computer

functions of the motherboard are:

- holds many components of the system.

- provides connectors for other peripherals. 

WHAT IS COMPONENTS OF MOTHERBOARD?

PROCESSOR SLOT	MEMORY SLOTS	ADAPTER CARD SLOTS
Holds a processor and forms the electrical interface with the CPU(central processing unit)	Hold memory modules, that are the Random Access Memory (RAM)	That can hold adapter cards

In this chapter, you have seen what a motherboard look like and you should be able to know how to locate various components on the motherboard. You should be able to look at a motherboard component and know what it does within the computer. Take the time to open up your computer and look at the motherboard and try to identify each component. You will be surprised at what you have learned.

CHAPTER 3 : LOGIC GATE & SIMPLE LOGIC CIRCUIT

Today I have another new knowledge to share with you all.

logic gate & simple logic circuit

Introduction
Boolen Algebra name from George Boole (mathematician) can convert human ways of expressing logical processes into a mathematical and electronic form for computation known as symbolic iogic, or Boolen Algebra.
computers are built as collection of switches that either "on" or "off", Boolen Algebra is a very natural way to present digital information.
Boolen Algebra is a logical algebra.
the variables take on two values corresponding to truth (1 or T) and false (0 or F).

value 1 represent true (T)

value 0 represent false (F)

Boolen Algebra use three basic logical operators :   AND , OR  and  NOT. 

A logic gate is an elementary building block of a digital circuit. Most logic gates have two inputs and one output. At any given moment, every terminal is in one of the two binaryconditions low (0) or high (1), represented by different voltage levels. The logic state of a terminal can, and generally does, change often, as the circuit processes data. In most logic gates, the low state is approximately zero volts (0 V), while the high state is approximately five volts positive (+5 V).

There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.

The AND gate is so named because, if 0 is called "false" and 1 is called "true," the gate acts in the same way as the logical "and" operator. The following illustration and table show the circuit symbol and logic combinations for an AND gate. (In the symbol, the input terminals are at left and the output terminal is at right.) The output is "true" when both inputs are "true." Otherwise, the output is "false."

AND gate

Input 1	Input 2	Output
	1
1
1	1	1

The OR gate gets its name from the fact that it behaves after the fashion of the logical inclusive "or." The output is "true" if either or both of the inputs are "true." If both inputs are "false," then the output is "false."

OR gate

Input 1	Input 2	Output
	1	1
1		1
1	1	1

A logical inverter , sometimes called a NOT gate to differentiate it from other types of electronic inverter devices, has only one input. It reverses the logic state.

Inverter or NOT gate

Input	Output
1
	1

The NAND gate operates as an AND gate followed by a NOT gate. It acts in the manner of the logical operation "and" followed by negation. The output is "false" if both inputs are "true." Otherwise, the output is "true."

NAND gate

Input 1	Input 2	Output
		1
	1	1
1		1
1	1

The NOR gate is a combination OR gate followed by an inverter. Its output is "true" if both inputs are "false." Otherwise, the output is "false."

NOR gate

Input 1	Input 2	Output
		1
	1
1
1	1

Using combinations of logic gates, complex operations can be performed. In theory, there is no limit to the number of gates that can be arrayed together in a single device. But in practice, there is a limit to the number of gates that can be packed into a given physical space. Arrays of logic gates are found in digital integrated circuits (ICs). As IC technology advances, the required physical volume for each individual logic gate decreases and digital devices of the same or smaller size become capable of performing ever-more-complicated operations at ever-increasing speeds.

for example 

alright, this is for today. enjoy it!

CHAPTER 1 :INTRODUCTION TO INFORMATION TECHNOLOGY

Hello! 

now, i would to post about chapter 1 in computer science that is namely introduction to information technology. 

so, in this chapter, you should know about definition of IT, atleast 2 advantages and 2 disvantages of IT, all application of IT and all the categories of computer.

thank you for reading =).

CHAPTER 2 : SYSTEM CONCEPT

today, i would to share to you about chapter 2 in computer science (computer system)

computer system has two subtopics which is system concept and number system and representation

Input, processing, output and storage are the activities that perfomed by computer. We must know how to draw information processing cycle. Parellel shape is for input and output, rectangle is for process and cylinder shape is for storage. 

Data can be represented by using 2 binary digits : 1(on) -  0(off). 8 bits combined together to represent a data. 

storage capacity - The amount of data a storage device such as a disk or tape can hold. Storage capacity is measured in kilobytes (KB), megabytes (MB), gigabytes (GB) and terabytes (TB). See space/time, magnetic disk, magnetic tape and optical disc.

When working with any kind of digital electronics in which numbers are being represented, it is important to understand the different ways numbers are represented in these systems.The number system based on ones and zeroes is called the binary system (because there are only two possible digits).

 It is cumbersome for humans to deal with writing, reading and remembering individual bits, because it takes many of them to represent even fairly small numbers. A number of different ways have been developed to make the handling of binary data easier for us. The most common is hexadecimal. In hexadecimal notation, 4 bits (a nibble) are represented by a single digit. There is obviously a problem with this since 4 bits gives 16 possible combinations, and there are only 10 unique decimal digits, 0 to 9. This is solved by using the first 6 letters (A..F) of the alphabet as numbers. The table shows the relationship between decimal, hexadecimal and binary.

Decimal	Hexadecimal	Binary
0	0	0000
1	1	0001
2	2	0010
3	3	0011
4	4	0100
5	5	0101
6	6	0110
7	7	0111
8	8	1000
9	9	1001
10	A	1010
11	B	1011
12	C	1100
13	D	1101
14	E	1110
15	F	1111

So far we have seen the different ways that binary can be used to store numbers. As we already know, most computers can only understand binary and we often need to store alpha-numeric text (numbers, letters and other characters). To do this a computer will use a coding scheme. The most popular coding schemes are ASCII, EBCDIC and Unicode. You'll need to know how each works and the benefits and drawbacks of using them.

There are two reasons to use ASCII. First, we need some way to represent characters as binary numbers (or, equivalently, as bitstring patterns). There's not much choice about this since computers represent everything in binary.The other reason we use ASCII is because of the letter "S" in ASCII, which stands for "standard". Standards are good because they allow for common formats that everyone can agree on.Another character representation that was used (especially at IBM) was EBCDIC, which stands for Extended Binary Coded Decimal Interchange Code (yes, the word "code" appears twice). This character set has mostly disappeared. EBCDIC does not store characters contiguously, so this can create problems alphabetizing "words".Thus, a new character set called Unicode is now becoming more prevalent. This is a 16 bit code, which allows for about 65,000 different representations. This is enough to encode the popular Asian languages (Chinese, Korean, Japanese, etc.). It also turns out that ASCII codes are preserved. What does this mean? To convert ASCII to Unicode, take all one byte ASCII codes, and zero-extend them to 16 bits. That should be the Unicode version of the ASCII characters.

so, here is the comparison between ASCII, EBCDIC AND Unicode.

that's all for today. hope this post would help you in computer science. bye.