S1 ICT | Input, Process, Output, Storage, Bits and File Size Prep Guide (for tutors)

S1 ICT | Input, Process, Output, Storage, Bits and File Size Prep Guide (for tutors) | How many photos fit on 4 GB

2026-11-06

Every S1 student can switch a computer on, yet few can say which step the keyboard belongs to, and most answer 4000 when asked how many megabytes are in 4 gigabytes. Nobody ever told them that a computer only knows 0 and 1, and that 1024 is its version of 1000.

Objectives — Students can: (1) place keyboard, screen, memory and hard disk into input, process, output and storage; (2) separate hardware from software with three examples each; (3) convert KB, MB and GB by 1024 and calculate that 4 GB holds 1365 photos of 3 MB.

01 Prerequisites (3-minute check)

If any of these fails, fix it before the lesson starts.

Skill	Quick check	Pass mark
Multiplication	What is 1024 times 1024	1,048,576
Unit sense	How many centimetres in a metre	100, because metric units step by ten
Classifying	Sort objects into data in and data out	Keyboard in, screen out

02 Lesson flow (60 minutes)

Time	Stage	Tutor does	Student does
0-5 min	What a computer does	Walk through typing a message and seeing a reply, asking what happened	Name the four actions aloud
5-17 min	The four steps	Place eight devices under the four steps, stress that the CPU only calculates	Sort the eight devices themselves
17-29 min	Hardware and software	Split system software from application software, three examples each	Write three plus three examples
29-41 min	Bits and 1024	Use a light switch to show 0 and 1, then eight bits to a byte	State how many bits make a byte
41-53 min	Capacity	Multiply by 1024 step by step, then divide 4 GB by 3 MB	Work out 1365 photos themselves
53-60 min	Exit check	Collect and mark three questions, name the act each error came from	Work independently

03 Teaching script (read it out)

Scene 1: Four steps: input, process, output, storage

Every computer does the same four things: takes data in, calculates, gives a result, keeps it. The names are input, process, output and storage.
Keyboard, mouse, microphone and scanner are input. The processor and memory do the processing. Screen, speaker and printer are output. Hard disk, USB drive and cloud storage are storage.
Two traps worth naming: a touch screen is both input and output, so it always appears in classification questions; memory (RAM) is the desk used while working and loses everything when power goes, so it is not storage.

Students do: sort eight devices into four boxes and explain why the touch screen appears twice.

Scene 2: Hardware and software

Hardware can be touched; software is the instructions that cannot. Software splits into two layers: system software runs the machine (operating system, drivers) and application software does work for people (word processor, browser, games).
The common S1 confusion is whether an app is hardware. Anything installed is software, even though it occupies space on the disk.
One more distinction: a file is not hardware. A photo file lives on hardware, but the file itself belongs to the software layer as data.

Students explain: which of the camera lens and the camera app is hardware.

Scene 3: Bits, bytes and 1024

A computer knows two states, current on and current off, written 1 and 0, and one such unit is a bit. Eight bits make a byte, and one English letter takes about one byte.
Because the machine counts in binary, each step multiplies by 1024 rather than 1000: 1 KB is 1024 bytes, 1 MB is 1024 KB (1,048,576 bytes), 1 GB is 1024 MB (1,073,741,824 bytes).
So a 4 GB drive holds 4 times 1,073,741,824, which is 4,294,967,296 bytes, not 4,000,000,000. A 3 MB photo is 3,145,728 bytes, and dividing gives 1365 photos.

Students do: calculate 4 GB against 3 MB photos, write 1365, and explain why it is not 1333.

04 Question types and worked steps

Type	Example	Steps	Answer
Classification	Which step does a mouse belong to	Ask whether it takes data in, gives results out, or keeps data	Input
Hardware or software	Is an operating system hardware	Cannot be touched means software; then ask whether it runs the machine or helps the user	System software
Unit conversion	How many MB in 2 GB	Multiply by 1024 at each step	2048 MB
Capacity calculation	Photos of 3 MB on a 4 GB drive	Convert to the same unit first, then divide and round down	1365 photos

Sanity check (teach this): A conversion to a smaller unit must give a bigger number, so a shrinking answer means the division went the wrong way. One MB is eight times one Mb, so capital and small letters are not interchangeable. 4 GB is larger than 4,000,000,000 bytes, and an answer of 4000 MB means decimal counting crept in. A photo count is a whole number and does not change when the file is copied.

05 Independent practice (3 questions)

Question	Answer	What to watch
Sort eight devices	Place them into the four steps	Check RAM is not called storage
Convert	How many MB in 2 GB	Check 1024 is used, not 1000
Capacity	Photos of 3 MB on 4 GB	Check units were unified before dividing

06 Common mistakes and what to say

Mistake	Student writes	Say this
Counting by 1000	4 GB is 4000 MB	A computer rolls over at 1024 because it only has 0 and 1. Using 1000 loses a chunk of your answer.
RAM as storage	Memory is for keeping photos	Will the photo still be there after power off? Only then is it storage, and RAM empties on shutdown.
Ignoring letter case	1 MB is the same as 1 Mb	Capital B is a byte, small b is a bit, eight times apart. Units are part of the name.
Touch screen as output only	The screen only shows the picture	When you press it, does it receive your instruction? Then it is input as well.

07 Homework (paper, section and question numbers)

Secondary ICT chapter index — All chapters in one place
Prep guide index — The same kind of chapter for other subjects
Redo this chapter — Recalculate with a 32 GB drive and 5 MB photos, showing all three steps

08 Exit check (last 5 minutes)

Question	Answer	Decision
Which step is the keyboard	Input	Answering process means act one again
How many KB in 1 MB	1024 KB	Answering 1000 means act three again
Photos of 3 MB on 4 GB	1365	Answering 1333 means act three again

09 Tutor FAQ

Why does a 500 GB disk show less in the system?

Manufacturers label in decimal while the operating system counts in 1024, and system files take space, so the reported figure is a few percent lower.

Should S1 learn binary conversion?

Only the idea and the 1024 steps. Bit-by-bit conversion belongs to S3, and drilling it at S1 buries the four-step model.

How do RAM and a hard disk differ in one line?

RAM is the desk you work on and the disk is the cupboard; a bigger desk works faster, a bigger cupboard stores more.

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A TutorZone lesson-prep guide. Written by the TutorZone team; questions and lesson flow are original and are not taken from any school or publisher material.