S4 Computer Systems Flashcards
What is a computer system?
A combination of hardware and software designed to input, process, store and output data.
What is hardware?
The physical components of a computer system such as the CPU, memory, and peripherals.
What is software?
The programmes and operating systems that run and hardware on perform tasks.
How do hardware and software work together?
Hardware provides the physical platform, while software runs on it to perform tasks. Software depends on hardware to function, and hardware is useless without software.
Draw the NOT gate
Draw the AND gate
Draw the OR gate
Draw the XOR gate
What does the NOT gate do?
It inverts the input:
If input = 1, output = 0
If input = 0, output = 1
What does the AND gate do?
It outputs 1 only if both inputs are 1.
What does the OR gate do?
It outputs 1 if at least one input is 1.
What does the XOR gate do?
It outputs 1 if only one of the inputs is 1, but not both.
Boolean algebra for a NOT gate?
A̅
Boolean algebra for an AND gate?
A * B
Boolean algebra for an OR gate?
A + B
Boolean algebra for an XOR gate?
A ⊕ B
What is system software?
Software that manages hardware and provides a platform for application software, e.g., operating systems and utility programs.
Describe the term application software
software that performs end-user tasks
Describe the term system software
- Manages computer hardware;
- Manages application software;
- Manages a computer (system);
- Manages the operation of the computer (system);
What are the key functions of an operating system?
- Processor management (allocates CPU time)
- Memory management (manages RAM and virtual memory)
- Device management (controls input/output devices)
- Application management (runs software)
- Security management (user authentication, firewalls)
What is an Operating System?
An operating system (OS) is software that manages computer hardware and software resources and provides services for computer programs.
Examples of Operating Systems
Windows (Microsoft), macOS (Apple), Linux (Open-source), Android (Google – Mobile OS), iOS (Apple – Mobile OS).
What is an operating system (OS)?
A set of programs that manage a computer’s hardware and software.
What are the five key management functions of an OS?
Processor management, Memory management, I/O device management, Application management, Security management.
How does an OS manage the processor?
It allocates CPU time to tasks, switching between them using time slices in a multitasking system.
What happens when a computer has multiple processor cores?
The OS distributes tasks across cores to improve efficiency.
How does an OS manage memory?
It allocates memory to programs and files, ensuring efficient use of RAM.
What happens when a program is closed?
The OS frees up the allocated memory for other applications.
What is an I/O device?
Any device that inputs or outputs data (e.g., keyboard, mouse, printer, monitor).
How does the OS manage I/O devices?
It uses device drivers to translate data between the hardware and software.
What is a device driver?
A small program that allows the OS to communicate with hardware devices.
How does an OS manage applications?
It allocates memory & CPU time, allows applications to communicate, and provides a user interface.
What is an API (Application Programming Interface)?
A system that allows applications to interact with the operating system.
How does an OS handle security?
It controls access using passwords, user privileges, automatic updates, and encryption.
How does an OS manage users on a network?
It tracks active users, logs user activity, and enforces access rights.
What is an embedded system?
A computer system built into a device to perform a dedicated function.
Give three examples of embedded systems.
Microwave ovens, traffic lights, smart meters.
How do embedded systems differ from non-embedded systems?
Fixed purpose vs. general purpose, Stored in ROM and rarely updated, More reliable & efficient.
What does encryption software do?
Converts data into ciphertext to prevent unauthorized access.
Why are firewalls and antivirus software important?
They protect the system from viruses, malware, and hacking attempts.
What is disk defragmentation?
A process that organizes fragmented files on a hard drive to improve speed.
Why do SSDs not need defragmentation?
SSDs access data electronically, so fragmentation doesn’t slow them down.
What does automatic updating do?
It downloads & installs security patches and software updates automatically.
What does compression software do?
Reduces file size for storage or faster transmission.
What are the two types of compression?
Lossy – Removes data permanently (e.g., JPEG). Lossless – Keeps all data (e.g., ZIP files).
What are the two levels of programming languages?
High-level languages and low-level languages.
What is the difference between high-level and low-level languages?
High-level: Easier for humans to read (e.g., Python). Low-level: Closer to machine code (e.g., Assembly).
What are the two types of low-level languages?
Machine code and assembly language.
Why are most programs written in high-level languages?
They are easier to write, debug, and maintain.
What are the three types of program translators?
Compiler, interpreter, assembler.
How does a compiler work?
Translates entire code at once, making execution faster.
How does an interpreter work?
Translates line by line, allowing real-time debugging.
What does an assembler do?
Converts assembly language into machine code (1:1 instruction mapping).
What is the Von Neumann architecture?
A design model where a computer’s CPU fetches, decodes, and executes instructions stored in memory.
What are the four major components of the CPU?
ALU, Control Unit, Registers, Bus.
What is the function of the ALU (Arithmetic Logic Unit)?
Performs calculations and logical decisions.
What is the function of the Control Unit (CU)?
Directs operations and controls the flow of data.
What are the three steps of the Fetch-Execute cycle?
Fetch – Retrieves instruction from memory. Decode – Interprets the instruction. Execute – Carries out the operation.
What are the four types of memory in a computer?
RAM, ROM, Cache, Registers.
What’s the difference between RAM and ROM?
RAM: Volatile, temporary storage. ROM: Non-volatile, stores BIOS.
What is the purpose of secondary storage?
Provides long-term data storage for programs and files.
What are the three types of secondary storage?
Solid-state, optical, magnetic.
How does cloud storage differ from local storage?
Data is stored remotely on servers instead of a physical device.
