1.2 Hardware and Software – Comprehensive Notes
Hardware
Hardware refers to all of the physical devices that make up a computer; a computer is a system of devices that work together, like instruments in a symphony.
When shopping for a computer, you’ll see components such as microprocessors, memory, disk drives, video displays, graphics cards, etc.
A typical computer system consists of the following major components: the central processing unit (CPU), the main memory, secondary storage devices, input devices, and output devices (refer to Figure 1-2).
The computer runs or executes a program when performing the tasks that the program tells it to do.
Central Processing Unit (CPU)
The CPU is the part of the computer that actually runs the programs; it is the most important component because without it the computer cannot run software.
In early computers CPUs were large, built from electrical and mechanical components like vacuum tubes and switches.
ENIAC: considered by many the world’s first programmable electronic computer; built in 1945 to calculate artillery ballistic tables for the US Army; it was essentially one big CPU, eight feet tall, 100 feet long, and weighed about 30 tons ().
Modern CPUs are small chips called microprocessors (Figure 1-4 shows a lab technician with a microprocessor).
The evolution from ENIAC to microprocessors shows a dramatic increase in size reduction and power.
When a program runs, the CPU performs the instructions of the program; execution of a program means the computer is running that program.
Main memory (RAM)
Main memory is the computer’s work area; it stores a program while it is running as well as the data the program works with.
RAM stands for Random Access Memory because the computer can quickly access data stored at any random location in RAM.
RAM is usually volatile; its contents are lost when the computer is turned off.
RAM is implemented as memory chips (Figure 1-5).
Example: while using a word processing program to write an essay, both the word processing program and the essay are stored in main memory.
Secondary storage
Secondary storage holds data for long periods, even when there is no power; it is non-volatile.
Programs are normally stored in secondary storage and loaded into RAM as needed.
Important data (e.g., documents, payroll data, inventory records) is saved to secondary storage.
The most common secondary storage device is a disk drive; traditional disk drives store data on magnetically encoded spinning disks.
Solid-state drives (SSDs) store data in flash memory; they have no moving parts and operate faster than traditional disk drives.
Most computers have some form of secondary storage (disk drive or SSD) mounted inside the case.
External storage
External storage devices connect via the computer’s communication ports (e.g., USB) and are used to back up data or move data to another computer.
USB drives (memory sticks/flash drives) plug into USB ports and appear to the system as a disk drive, even though they do not contain a traditional disk.
USB drives store data in flash memory and are inexpensive, reliable, and portable.
Input devices
Input is any device that collects data from people or other devices and sends it to the computer.
Common input devices: keyboard, mouse, touchscreen, scanner, microphone, digital camera.
Disc drives and optical drives can also be considered input devices because data/programs are retrieved from them and loaded into memory.
Output devices
Output is any data the computer produces for people or other devices.
It can be a sales report, a list of names, or a graphic image.
The data is sent to an output device, which formats and presents it.
Common output devices: video displays and printers.
Disc drives can also be considered output devices because data is saved to them.
Software
Software is essential for a computer to function; everything the computer does from power-on to shutdown is controlled by software.
There are two general categories of software: system software and application software.
System software
System software controls and manages the basic operations of a computer.
It typically includes:
Operating systems
Utility programs
Software development tools
Operating systems (OS) are the most fundamental set of programs on a computer.
OS functions:
Control internal hardware operations
Manage devices connected to the computer
Allow data to be saved to and retrieved from storage devices
Allow other programs to run on the computer
Popular desktop/laptop OSs: Windows, macOS, Linux.
Popular mobile OSs: Android, iOS.
Utility programs perform specialized tasks that enhance operation or safeguard data (e.g., virus scanners, file compression, data backup).
Software development tools are used by programmers to create, modify, and test software (assemblers, compilers, interpreters).
Application software
Application software enables people to perform everyday tasks on a computer.
Common examples include word processing, spreadsheets, email, web browsers, and games.
Figure 1-1 (referenced in the chapter) shows screenshots from Microsoft Word and PowerPoint as examples of application software.
Some other examples of application software: spreadsheet programs, email programs, web browsers, and game programs.
1.2 Non-interactive Checkpoint Questions (from the book)
1.1 What do you call a program that performs a specialized task such as a virus scanner, a file compression program, or a data backup program?
1.2 What is hardware?
1.3 List the five major components of a computer system.
1.4 What part of the computer actually runs programs?
1.5 What part of the computer serves as a work area to store a program and its data while the program is running?
1.6 What part of the computer holds data for long periods of time even when there is no power to that computer?
1.7 What part of the computer collects data from people and from other devices?
1.8 What part of the computer formats and presents data for people or other devices?
1.9 What fundamental set of programs control the internal operations of the computer's hardware?
1.11 Word processing programs, spreadsheet programs, email programs, web browsers, and game programs belong to what category of software?
Notes and connections
Hardware is a system: each component has a role, and performance emerges from their interaction.
The CPU’s evolution highlights a foundational principle: computation power increases with integration and reduced physical size (from ENIAC’s vacuum tubes to modern microprocessors).
RAM vs. secondary storage illustrates a key design trade-off: fast, volatile, temporary workspace vs. slower, persistent storage for long-term data.
External storage (USB drives) emphasizes portability and the importance of backups and data transfer, as well as security considerations (loss or theft risks).
Input vs. output devices show how computers interface with humans and other systems; some devices (disc/optical drives) can function as both input and output depending on data flow.
System software vs. application software clarifies roles: OS manages hardware and provides services; applications enable user tasks.
Practical implications include data backup practices, security (virus scanners), data integrity (compression and backups), and the importance of choosing appropriate OS and software tools for tasks.
Real-world relevance: understanding hardware/software helps in selecting devices, diagnosing issues, and evaluating performance for tasks like word processing, data analysis, and multimedia presentations.
Foundational principles touched upon include abstraction (OS abstracts hardware), volatility vs. persistence (RAM vs. disk/SSD), and the trade-offs between speed, cost, and durability.
1.2 Non-interactive Checkpoint Questions (from the book)
1.1 What do you call a program that performs a specialized task such as a virus scanner, a file compression program, or a data backup program?
Answer: Utility programs
1.2 What is hardware?
Answer: Hardware refers to all of the physical devices that make up a computer.
1.3 List the five major components of a computer system.
Answer: The central processing unit (CPU), the main memory, secondary storage devices, input devices, and output devices.
1.4 What part of the computer actually runs programs?
Answer: The Central Processing Unit (CPU).
1.5 What part of the computer serves as a work area to store a program and its data while the program is running?
Answer: Main memory (RAM).
1.6 What part of the computer holds data for long periods of time even when there is no power to that computer?
Answer: Secondary storage.
1.7 What part of the computer collects data from people and from other devices?
Answer: Input devices.
1.8 What part of the computer formats and presents data for people or other devices?
Answer: Output devices.
1.9 What fundamental set of programs control the internal operations of the computer's hardware?
Answer: Operating systems (OS).
1.11 Word processing programs
Answer: Application software