Computer hardware: input, processing, output, storage
FoundationHardware falls into four groups: input (get data in), processing (the CPU thinks), output (show results) and storage (keep data). The CPU is the brain, RAM is the desk, storage is the bookshelf.
- Four hardware jobs: input, processing, output, storage
- CPU = brain (processing); RAM = desk (temporary, wiped at shutdown)
- Disk/SSD = bookshelf (long-term storage)
§Text Passage
1However sleek a computer looks, it is basically four kinds of parts working together: input devices pass data in, such as the keyboard, mouse and scanner; the central processing unit (CPU), which sits on the motherboard, does the computing; output devices present the results, such as the monitor and printer; and storage devices keep files long-term, such as hard disks and SSDs. Get these four roles clear and hardware questions are half answered.
2In daily use the four steps keep cycling: when typing in an ICT lesson, the keyboard sends characters in, the CPU processes them, the monitor displays them at once, and saving writes the file to the disk. Tapping an Octopus card runs the same four stages — reading the card (input), calculating the fare (processing), showing the balance (output) and logging the transaction (storage) — just too fast to notice; the parts interlock, and nothing works if any one of them is missing.
3Hong Kong example: a public library self-service kiosk scans your library card (input), queries the system (processing), shows 'borrowed' on the screen (output) and writes the record into its database (storage). When shopping for a computer, learning to read spec labels such as 'Core i5, 16GB RAM, 512GB SSD' — processor, memory and storage respectively — helps you judge whether the performance matches the price.
1Summary 重點摘要
Hardware falls into four groups: input (get data in), processing (the CPU thinks), output (show results) and storage (keep data). The CPU is the brain, RAM is the desk, storage is the bookshelf.
2Vocabulary cards Vocabulary
The physical parts of a computer you can touch, e.g. keyboard, screen, CPU.
The brain of the computer — runs program instructions and does the calculating.
Holds data currently in use; it is wiped when the power goes off.
Keeps files long-term, e.g. hard disk (HDD), SSD, USB flash drive.
Sends data into the computer, e.g. keyboard, mouse, microphone, camera.
Shows results to you, e.g. monitor, printer, speakers.
The main circuit board connecting all the parts; the CPU and RAM sit on it.
Both input and output: it shows the picture and senses your touch.
3Step by step Steps
- Four groupsComputer hardware can be sorted by function into four groups: input devices send data into the computer, e.g. keyboard, mouse, touchscreen, scanner, microphone, camera; processing is done by the CPU, which sits on the motherboard; output devices show the results, e.g. monitor, printer, speakers; storage devices keep files long-term, e.g. hard disk, SSD, USB drive. When answering, decide each device's main function first, then name its group, and nothing will be left out or mismatched.
- CPU = the brainEvery instruction is executed by the CPU; the faster the CPU, the faster the computer finishes its work, which is why it is called the brain of the computer. The motherboard is like the skeleton of the body, connecting all the parts so data can travel between them. When buying a computer, the CPU model and level directly affect performance — with a faster CPU, running many programs at once, playing videos or playing games clearly goes more smoothly. A common misconception is that RAM decides the speed; RAM only decides how much data can be handled at once.
- RAM vs storageRAM is like a desk: the data you are working on sits on it — fast to access but limited in size, and completely cleared when the power goes off. A hard disk or SSD is like a bookshelf: large capacity and keeps files for years, but reading and writing is slower. The two roles differ and cannot replace each other. For example, when you open a document it is first read from the disk into RAM; if the power suddenly cuts at that moment, unsaved changes are gone. A common mistake is thinking RAM keeps data after shutdown — always state in your answer that RAM is temporary storage.
- They work togetherTake typing a report as an example: the keyboard sends characters into the computer (input), the CPU calculates and processes the document (processing), the screen shows the text at once (output), and saving writes the file to the disk or SSD (storage). The four parts link together, and the work cannot be finished if any one of them is missing. Daily life offers many more: paying by Octopus — the reader inputs the data, the system computes the fare, the screen shows the balance, and the record is written into the database. Answer in the order input, processing, output, storage to earn every mark.
- Touchscreens are specialA touchscreen has a special double identity: it is an output device, showing the picture to the user, and also an input device, sensing where and how your finger touches. For example, when tapping a button on a phone, the screen first displays the button (output) and then senses the touch of the fingertip (input) — both on the same panel. This dual role is a hot exam point: write both functions clearly or marks will be lost. Tablets, restaurant ordering machines and bank ATM screens all work the same way.
- Reading the spec labelComputer advertisements often read 'Intel Core i5, 16 GB RAM, 512 GB SSD': the first item is the CPU model, which decides processing speed; the second is the RAM size — more of it lets you run many programs at once without lag; the third is the SSD capacity, which decides how many files you can keep long-term — 512 GB holds roughly a hundred thousand phone photos. Compare these three first to judge whether a computer's performance matches its price. A common mistake is reading 16 GB RAM as storage space and expecting it to hold more files; it only affects how much you can do at once — long-term storage depends on the SSD or hard disk capacity.
4Diagrams Diagrams
5Worked example Example
Example: sort these devices — scanner, SSD, speakers, CPU.
- Ask of each device: does it bring data into the computer, send results out, do the computing, or keep files long-term? Function first, group second.
- The scanner reads documents into the computer, so the direction is 'in' — it is an input device; speakers play sound out, so they are output devices.
- An SSD keeps files long-term, so it is storage; the CPU runs instructions and does the calculating, so it is the processing part — neither is input nor output.
- Answer format: state the function, then the group, e.g. 'a scanner reads documents in, so it is an input device' — both parts are needed for full marks.
- Watch the trap: a touchscreen is both input and output; if it appears in the question, state both roles to be complete.
- Answer: The scanner reads documents into the computer, so it is an input device; the SSD keeps files long-term, so it is storage; the speakers play sound out, so they are output devices; the CPU runs instructions and calculates, so it is the processing part. Sort by the direction of data flow and the function of each device — state the function first, then the group, and the answer is complete; for a dual-role device like a touchscreen, write both functions.
6Common mistakes Mistakes
7Quick check Quick check
Q1Which part is the brain that processes instructions? A. RAM B. CPU C. printer
Q2After shutting down, the data inside which device disappears?
Q3Is a touchscreen an input or output device?
Q4Which group is all input devices? A. keyboard, scanner, microphone B. monitor, speakers, printer C. hard disk, SSD, USB drive
Q5You typed a document but never saved it, then the power cut. Is the text still there after restarting? Why?
8Recap Recap
- Four hardware jobs: input, processing, output, storage
- CPU = brain (processing); RAM = desk (temporary, wiped at shutdown)
- Disk/SSD = bookshelf (long-term storage)
- A touchscreen is both input and output
- Get the four groups clear and hardware questions are half solved