Operating system (OS)
💎 Operating system coordinates the activity between the user and the computer.
💎 It serves as an intermediary between programs and hardwares.
Types of Operating Systems:
i. Single-user / Single tasking OS
📌 Only one program can be
run on a computer at a time.
📌 Also can serve only
one user at a time.
ii. Single-user / multi-tasking OS
📌 desktop and laptop computers now day
📌 popular OS's Like
💎Linux (Ubuntu)
💎Windows
💎macOS
iii. Multi-user
📌 Unix, VMS and mainframe operating systems, such as MVS (Multiple Virtual Storage).
iv. Real Time Operating System
📌 is capable of processing data so quickly that the results are available to influence the activity currently taking place.
📌 are used to control machinery, scientific instruments and industrial systems.
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💎 Operating system coordinates the activity between the user and the computer.
💎 It serves as an intermediary between programs and hardwares.
Types of Operating Systems:
i. Single-user / Single tasking OS
📌 Only one program can be
run on a computer at a time.
📌 Also can serve only
one user at a time.
ii. Single-user / multi-tasking OS
📌 desktop and laptop computers now day
📌 popular OS's Like
💎Linux (Ubuntu)
💎Windows
💎macOS
iii. Multi-user
📌 Unix, VMS and mainframe operating systems, such as MVS (Multiple Virtual Storage).
iv. Real Time Operating System
📌 is capable of processing data so quickly that the results are available to influence the activity currently taking place.
📌 are used to control machinery, scientific instruments and industrial systems.
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2. Language Software
💎Are software which are used by programmers to develop application software and translate programs to machine code.
💎Language software is a generic name consisting of various programs that serve as
📌 editors
📌 and translators to develop programs in a number of programming languages.
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💎Are software which are used by programmers to develop application software and translate programs to machine code.
💎Language software is a generic name consisting of various programs that serve as
📌 editors
📌 and translators to develop programs in a number of programming languages.
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Translator
💎 program that converts one or more languages to another language.
▶️ Three types of translators
I) Assemblers:
is a program that translates assembly languages into machine code.
II) Compiler:
is a program that translates a high level language into machine code.
>> creates an executable program.
📌 C++, JAVA, C# and e.t.c
III) Interpreter:
is a program that translates each instruction of high level language & executes the instruction before translating the next instruction.
📌 PHP, JAVASCRIPT, PYTHON and e.t.c
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💎 program that converts one or more languages to another language.
▶️ Three types of translators
I) Assemblers:
is a program that translates assembly languages into machine code.
II) Compiler:
is a program that translates a high level language into machine code.
>> creates an executable program.
📌 C++, JAVA, C# and e.t.c
III) Interpreter:
is a program that translates each instruction of high level language & executes the instruction before translating the next instruction.
📌 PHP, JAVASCRIPT, PYTHON and e.t.c
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▶️ High-level programming languages
Vs
▶️ Low-level programming languages
▶️ A High-level language
is a programming language designed to simplify computer programming.
💎 High-level source code contains easy-to-read syntax for human.
💎 Most common programming languages are considered
high-level languages.
C++, C#, Java, JavaScript, PHP, Python...
▶️ A Low-level language
💎 is a programming language that deals with a computer's hardware components and constraints.
💎 May also be referred to as a computer’s native language.
💎 Machine language and assembly language are popular examples of low-level languages.
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Vs
▶️ Low-level programming languages
▶️ A High-level language
is a programming language designed to simplify computer programming.
💎 High-level source code contains easy-to-read syntax for human.
💎 Most common programming languages are considered
high-level languages.
C++, C#, Java, JavaScript, PHP, Python...
▶️ A Low-level language
💎 is a programming language that deals with a computer's hardware components and constraints.
💎 May also be referred to as a computer’s native language.
💎 Machine language and assembly language are popular examples of low-level languages.
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▶️ Procedural
Vs ▶️ Object Oriented
Vs ▶️ Structured programming languages
▶️ A procedural programming language
💎consists of a set of procedure calls and a set of code for each procedure. Example: BASIC
▶️ A structural programming language emphasizes on separating a program’s data from its functionality. Example: C
▶️ Object oriented languages are based on entities known as objects. Example: Java
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Vs ▶️ Object Oriented
Vs ▶️ Structured programming languages
▶️ A procedural programming language
💎consists of a set of procedure calls and a set of code for each procedure. Example: BASIC
▶️ A structural programming language emphasizes on separating a program’s data from its functionality. Example: C
▶️ Object oriented languages are based on entities known as objects. Example: Java
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Application Software
📌 Is software that is designed to perform tasks for the specific area or areas by using more than one installation.
📌 Are usually called application packages as they may include a number of programs along with operating instruction, documentation and so forth.
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📌 Is software that is designed to perform tasks for the specific area or areas by using more than one installation.
📌 Are usually called application packages as they may include a number of programs along with operating instruction, documentation and so forth.
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Virus
⚠️ Is the most common type of malware,
and it's defined as a malicious program that can execute itself and spreads by infecting other programs or files.
⚠️ A virus is a piece of software that can "infect" other programs by modifying them.
⚠️ Similar to biological virus: Replicates and Spreads Some exists to simply replicate
themselves.
⚠️ Others can do serious damage such as erasing file…
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⚠️ Is the most common type of malware,
and it's defined as a malicious program that can execute itself and spreads by infecting other programs or files.
⚠️ A virus is a piece of software that can "infect" other programs by modifying them.
⚠️ Similar to biological virus: Replicates and Spreads Some exists to simply replicate
themselves.
⚠️ Others can do serious damage such as erasing file…
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Worm
⚠️Is a type of malware that can self-replicate without a host program.
⚠️ Worms typically spread without any human interaction or directives from the malware authors.
⚠️ A Trojan horse is a malicious program that is designed to appear as a legitimate program.
⚠️ once activated following installation, Trojans can execute their malicious functions.
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⚠️Is a type of malware that can self-replicate without a host program.
⚠️ Worms typically spread without any human interaction or directives from the malware authors.
⚠️ A Trojan horse is a malicious program that is designed to appear as a legitimate program.
⚠️ once activated following installation, Trojans can execute their malicious functions.
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Spyware
⚠️ Is a kind of malware that is designed to collect information and data on users and observe their activity without users' knowledge.
Other types of malware include functions or features designed for a specific purpose.
Ransomware
⚠️ for example, is designed to infect a user's system and encrypt the data.
⚠️ Cybercriminals then demand a ransom payment from the victim in exchange for decrypting the system's data.
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⚠️ Is a kind of malware that is designed to collect information and data on users and observe their activity without users' knowledge.
Other types of malware include functions or features designed for a specific purpose.
Ransomware
⚠️ for example, is designed to infect a user's system and encrypt the data.
⚠️ Cybercriminals then demand a ransom payment from the victim in exchange for decrypting the system's data.
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Computer Number System
1. Bit:
📌 Is the smallest unit of data representation.
📌 Is a space that can hold a single state.
2. Byte:
📌 Is the smallest unit of data measurement.
📌 Is a single group of 8 bits. [1 Byte = 8 Bits.]
3. Word:
📌 Is a group of 8 Bytes. [1 word = 8 Bytes.]
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1. Bit:
📌 Is the smallest unit of data representation.
📌 Is a space that can hold a single state.
2. Byte:
📌 Is the smallest unit of data measurement.
📌 Is a single group of 8 bits. [1 Byte = 8 Bits.]
3. Word:
📌 Is a group of 8 Bytes. [1 word = 8 Bytes.]
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Decimal Number System
Z = {0,1,2,3,4,5,6,7,8,9};
Base = 10
📌 Each position to the left of a digit increases by a power of 10.
📌 Each position to the right of a digit decreases by a power of 10.
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Z = {0,1,2,3,4,5,6,7,8,9};
Base = 10
📌 Each position to the left of a digit increases by a power of 10.
📌 Each position to the right of a digit decreases by a power of 10.
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Binary Number System
📌 Has two states 1(ON state)
and 0(OFF state).
Z = {0,1};
Base = 2
Unsigned number representation
With n bits we can represent 2^n unsigned integer numbers.
⚠️Remember: This ^ Indicates The Power Of
❗️ Range: from 0 to 2^n -1
So with 8 bits we can represent 2^8 = (256) numbers from 0 to 2^8 -1 = (255).
📌 Each position to the left of a digit increases by a power of 2.
📌 Each position to the right of a digit decreases by a power of 2.
Example:
(11001)2 = 1*2^0 + 0*2^1 + 0*2^2 + 1*2^3 + 1*2^4
= (25)10
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📌 Has two states 1(ON state)
and 0(OFF state).
Z = {0,1};
Base = 2
Unsigned number representation
With n bits we can represent 2^n unsigned integer numbers.
⚠️Remember: This ^ Indicates The Power Of
❗️ Range: from 0 to 2^n -1
So with 8 bits we can represent 2^8 = (256) numbers from 0 to 2^8 -1 = (255).
📌 Each position to the left of a digit increases by a power of 2.
📌 Each position to the right of a digit decreases by a power of 2.
Example:
(11001)2 = 1*2^0 + 0*2^1 + 0*2^2 + 1*2^3 + 1*2^4
= (25)10
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Signed number representation
▶️ Here we would need to consider sign, meaning we represent both positive and negative numbers.
📌 Sign and magnitude
With this method we reserve the most significant bit of the left most bit for sign.
This bit is called sign bit.
range becomes from -2^n-1 -1 to 2^n-1 -1
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▶️ Here we would need to consider sign, meaning we represent both positive and negative numbers.
📌 Sign and magnitude
With this method we reserve the most significant bit of the left most bit for sign.
This bit is called sign bit.
range becomes from -2^n-1 -1 to 2^n-1 -1
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