computer system

• A computer is an electronic device that can be programmed to accept data, process it, and generate results
• A computer system consists of a central processing unit, memory, input/output devices, and storage devices
• All components of a computer system function together as a single unit to deliver the desired output
• A computer system can come in various forms and sizes, from high-end servers to personal desktops, laptops, tablets, and smartphones
• Central Processing Unit (CPU)
• The CPU is the electronic circuitry of a computer that carries out the actual processing and is commonly referred to as the brain of the computer
• The CPU is given instructions and data through programs, fetches the program and data from memory, performs arithmetic and logical operations, and stores the result back to memory
• The CPU has two main components: Arithmetic Logic Unit (ALU) and Control Unit (CU)
• Registers are part of the CPU chip and are used for storing data, instructions, or intermediate results
• Input Devices
• Input devices are used to send control signals to a computer and convert input data into a digital form acceptable by the computer system
• Examples of input devices include keyboard, mouse, scanner, touch screen, and voice input
• Data entered through input devices is temporarily stored in the main memory (RAM) of the computer system
• Output Devices
• Output devices receive data from a computer system for display or physical production
• Output devices convert digital information into human-understandable form
• Examples of output devices include monitor, projector, headphone, speaker, printer, and 3D printer
• Computer Memory
• A computer system needs memory to store data and instructions for processing
• Main or primary memory is used for temporary storage, while secondary memory (storage devices) is used for permanent storage and future use
• Computer systems use binary numbers (0 and 1) to store and process data
• Moore's Law introduced in 1965 by Intel co-founder Gordon Moore predicted that the number of transistors on a chip would double every two years while the costs would be halved
• Basic units of memory are called bits, which are grouped together to form words
• A 4-bit word is called a Nibble, examples of nibbles are 1001, 1010, 0010, etc.
• A two nibble word, i.e., 8-bit word is called a byte, examples of bytes are 01000110, 01111100, 10000001, etc.
• Bytes are grouped together to make bigger chunks or units of memory
• Primary memory in a computer system is essential for loading programs and data before processing
• Primary memory is of two types: Random Access Memory (RAM) and Read Only Memory (ROM)
• RAM is volatile and used to store data temporarily while the computer is working
• ROM is non-volatile and used as a small but faster permanent storage for contents that are rarely changed
• Cache memory is a high-speed memory placed between the CPU and primary memory to speed up operations by storing copies of frequently accessed data
• Secondary memory is non-volatile and has larger storage capacity than primary memory, examples include Hard Disk Drive (HDD), CD/DVD, Memory Card, etc.
• Data capturing involves gathering data from different sources in digital form, such as keyboard, barcode readers, remote sensors, etc.
• Data storage is the process of storing captured data for processing later, with numerous digital storage devices available in the market
• Data retrieval involves fetching data from storage devices for processing as per user requirement
• Data deletion can result from malfunctions, accidental erasure, or intentional deletion by hackers/malware
• Data recovery is the process of retrieving deleted, corrupted, and lost data from secondary storage devices
• Security concerns related to data include deletion by unauthorized persons or software, and unwanted recovery of data by unauthorized users
• Proper tools should be used to delete or shred data before disposing of old or faulty storage devices to mitigate data confidentiality threats
• Software is a set of instructions that operate the hardware of a computer system, comprising instructions and data to be processed using the computer hardware