ICS3U · Unit 1 test review

Intro to Computers: Test Review

Everything for the Unit 1 test on one page: the key facts from all 3 lessons, the mistakes that cost the most marks, and a practice test that points you back to the lessons you need.

Key facts

Components, Specifications and Building to a Need

Bottleneck rule: for any one workload, the slowest component involved sets the performance — spend there first.
Compatibility gates, in order: CPU socket matches the motherboard, RAM generation matches the board, PSU wattage covers the load, case clears the GPU and cooler.
PSU sizing: add the CPU and GPU draw, add about 75 W for everything else, then multiply by roughly 1.3 for headroom.
SATA III caps at 6 Gb/s, about 550 MB/s of real data; NVMe uses PCIe lanes directly and reaches several GB/s.
Dual channel doubles memory bandwidth, so two matched sticks beat one stick of the same total capacity.
Electrostatic discharge can damage a component invisibly today and cause a failure weeks later — ground yourself before touching anything.

How Computers Represent Data

Binary place values from the right: $1, 2, 4, 8, 16, 32, 64, 128$ — doubling each time.
An $n$ -bit pattern has $2^{n}$ possible values: unsigned they run $0$ to $2^{n} - 1$ , signed they run $- 2^{n - 1}$ to $2^{n - 1} - 1$ .
8 bits = 1 byte, and 4 bits = exactly 1 hex digit because $16 = 2^{4}$ .
Java int is 32 bits signed, so its range is $- 2147483648$ to $2147483647$ ; exceeding it wraps around silently.
1 KiB = 1024 bytes but 1 kB = 1000 bytes; lowercase b is bits, uppercase B is bytes.
ASCII: A is 65, a is 97 (always 32 apart), and the character 0 is 48.

Files, Folders and a Workspace That Works

An absolute path starts at the root and always means the same file; a relative path starts at the current working directory and survives moving the project.
In a relative path, . is the current folder and .. is the parent folder.
A file's real type is determined by its content (its signature bytes), not by its extension — renaming converts nothing.
Name files so they sort: ISO dates (YYYY-MM-DD), zero-padded numbers, no spaces.
3-2-1 backup: three copies, on two kinds of media, with one offsite.
Lossless compression restores the original exactly; lossy compression discards detail permanently.

Where marks get lost

Ranking two processors by gigahertz alone. A newer architecture does more work per cycle, so a 3.6 GHz chip regularly beats an older 4.2 GHz one. (Components, Specifications and Building to a Need)
Adding more RAM to a machine that was never running out, then wondering why nothing got faster. Extra RAM only helps once you were short. (Components, Specifications and Building to a Need)
Buying DDR5 memory for a DDR4 motherboard. The notch is in a different position and it will not seat, no matter how hard you press. (Components, Specifications and Building to a Need)
Sizing the power supply to exactly the calculated draw with no headroom, so the unit runs hot, loud and at its least efficient point. (Components, Specifications and Building to a Need)
Pairing a top-tier graphics card with a weak CPU (or the reverse) and calling the result a gaming build — an unbalanced pair wastes whichever part is faster. (Components, Specifications and Building to a Need)
Handling memory or a processor by its gold contacts, standing on carpet, with no wrist strap. The resulting damage often shows up weeks later. (Components, Specifications and Building to a Need)
Reading division-method remainders top-to-bottom, which silently reverses the entire binary answer. (How Computers Represent Data)
Splitting a binary number into nibbles from the LEFT. Always group in fours starting from the right and pad the left with zeros. (How Computers Represent Data)
Writing $2^{8} = 256$ and then claiming the largest 8-bit unsigned value is 256. It is 255, because counting starts at zero. (How Computers Represent Data)
Assuming a Java int can hold any whole number. It is 32 bits, so anything beyond 2 147 483 647 wraps around without an error message. (How Computers Represent Data)
Mixing up bits and bytes when a file size meets a connection speed — the factor of 8 makes the answer wrong by 800%. (How Computers Represent Data)
Treating hex letters as variables. In 0xB6, the B is the digit 11, not an unknown. (How Computers Represent Data)
Renaming a file's extension and believing the format changed. The bytes inside are untouched; only the operating system's guess about which program to use has changed. (Files, Folders and a Workspace That Works)
Naming Java files inconsistently with the class inside them — sorter.java holding public class Sorter will not compile. (Files, Folders and a Workspace That Works)
Writing dates as 9-Mar-2026 or 03/09/2026 in file names, so the folder sorts alphabetically by month or ambiguously between day and month order. (Files, Folders and a Workspace That Works)
Forgetting to zero-pad numbers, so lab10 sorts before lab2 and the whole folder reads out of order. (Files, Folders and a Workspace That Works)
Treating a synced cloud folder as a backup. It mirrors deletions and bad saves just as quickly as good work. (Files, Folders and a Workspace That Works)
Recording versions by copying files — Sorter_final_v3.java stores no record of what changed or which version actually worked. (Files, Folders and a Workspace That Works)

Practice test

18 questions from across the unit. Each one shows the lesson it comes from.

Components, Specifications and Building to a Need
1
A user edits 4K video and complains the timeline stutters whenever effects are added. Which upgrade addresses the most likely bottleneck?
Components, Specifications and Building to a Need
2
Why will a DDR5 memory module not fit a DDR4 motherboard?
Components, Specifications and Building to a Need
3
Name the CPU specification that must match the motherboard before any other part of a build can be considered.
Components, Specifications and Building to a Need
4
Put these assembly steps in the order a builder should perform them.
1. 1Install the graphics card and connect its power
2. 2Screw the motherboard onto the case standoffs
3. 3Install RAM and M.2 drives on the board
4. 4Fit the CPU into the socket while the board is out of the case
5. 5Mount the CPU cooler
Components, Specifications and Building to a Need
5
Why is electrostatic discharge damage especially frustrating to diagnose?
Components, Specifications and Building to a Need
6
Which statement about a graphics card is correct?
How Computers Represent Data
7
Convert $1100101 0_{2}$ to decimal.
How Computers Represent Data
8
Convert $0 x 2D$ to decimal.
How Computers Represent Data
9
What is the largest value a Java short can hold?
How Computers Represent Data
10
The ASCII code for 'M' is 77. What is the ASCII code for 'm'?
How Computers Represent Data
11
Order these values from smallest to largest.
1. 1 $0 x FF$
2. 2 $1100100 0_{2}$
3. 3 $6 0_{10}$
4. 4 $0000111 1_{2}$
5. 5 $0 x 2A$
How Computers Represent Data
12
An uncompressed image is 640 × 480 at 8-bit colour depth. How many bytes is it?
Files, Folders and a Workspace That Works
13
The working directory is project/src. Which relative path reaches project/data/input.txt?
Files, Folders and a Workspace That Works
14
Put these file names in the order a computer would sort them alphabetically.
1. 1lab3.java
2. 2lab20.java
3. 3lab2.java
4. 4lab1.java
5. 5lab10.java
Files, Folders and a Workspace That Works
15
A 400 MB folder of source code compresses to a 72 MB ZIP. What is the percentage reduction in size?
%
Files, Folders and a Workspace That Works
16
Which workstation adjustment most directly reduces neck strain?
Files, Folders and a Workspace That Works
17
A project folder is zipped for submission mainly because:
Files, Folders and a Workspace That Works
18
Which statement about compression is correct?

Endless drill

Fresh numbers every time, for the calculation questions in this unit.

Endless drillnew numbers every time

Generating a problem…