5 Questions
What is the primary function of the Control Unit in a CPU?
To retrieve and decode instructions
What type of storage is used to store data temporarily while it is being processed?
RAM
What is the purpose of the ALU in a CPU?
To execute arithmetic and logical operations
What is the role of the Operating System in managing memory?
To allocate memory for program execution
How many bits are in a nibble?
4
Study Notes
Computer Systems
- A computer is an electronic device that takes input, processes it, stores data, and produces output.
Fixed vs Programmable Computers
- Fixed computers perform a specific task and cannot be programmed to do anything else.
- Programmable computers can be programmed to perform a variety of tasks.
Calculators vs Computers
- Calculators are special-purpose computers that perform mathematical calculations.
- Computers are general-purpose devices that can perform various tasks beyond calculations.
Input and Output
- Input devices: keyboard, mouse, scanner, microphone, etc.
- Output devices: monitor, printer, speaker, etc.
RAM vs ROM
- RAM (Random Access Memory) is volatile memory that temporarily stores data and program instructions while the computer is running.
- ROM (Read-Only Memory) is non-volatile memory that permanently stores data and cannot be changed.
Secondary Storage
- Secondary storage is necessary because RAM is volatile and limited in capacity.
- Types of secondary storage: hard disk drives, solid-state drives, magnetic tapes, CDs, DVDs, Blu-ray discs.
- Technologies used: magnetic, optical, solid-state.
CPU (Central Processing Unit)
- Parts of a CPU:
- ALU (Arithmetic Logic Unit): performs mathematical and logical operations.
- Busses: connect different parts of the CPU.
- Clock: generates a synchronizing signal.
- Registers: small amount of on-chip memory.
- Control Unit: retrieves and executes instructions.
Operating System
- Roles of an operating system:
- Managing Memory: allocating memory to programs.
- Program Execution: loading and executing programs.
- Managing Input/Output: interacting with devices.
- Managing User Interface (GUI): providing a Graphical User Interface.
- Managing Communication: controlling communication between devices and the computer.
Binary System
- Binary is a number system with base 2, using only 0s and 1s.
- Converting Denary to Binary:
- Divide the denary number by 2 and note the remainder.
- Repeat step 1 until the quotient is 0.
- The binary representation is the sequence of remainders in reverse order.
- Converting Binary to Denary:
- Multiply each binary digit (starting from the right) by 2 to the power of its position (starting from 0).
- Add the products to obtain the denary equivalent.
Binary Maths
- Adding three binary numbers together:
- Perform binary addition for each column (right to left).
- Carry over any overflow to the next column.
Data Sizes
- Bit: a single binary digit.
- Nibble: a group of 4 bits.
- Byte: a group of 8 bits.
- Kilobyte (KB): 1024 bytes.
- Megabyte (MB): 1024 KB.
- Gigabyte (GB): 1024 MB.
- Terabyte (TB): 1024 GB.
Learn the fundamentals of computer systems, including the differences between fixed and programmable computers, input/output devices, RAM/ROM, secondary storage, and CPU components.
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