Hardware, Memory & Number Systems
🔒 Log in to trackMemory hierarchy and units, binary/octal/decimal/hex conversions, input-output devices, ports and storage media. Number-conversion and memory-unit questions are near-guaranteed marks because they need no theory recall - only method.
One page per subtopic: detailed notes, every question type, formulas, tricks and practice sets.
Every formula on one printable page, grouped by subtopic.
5 exam-level questions worked step by step.
97 questions — untimed practice or a timed test with analysis.
Track record in the exam
Test difficulty mix (97 questions)
Question patterns exams keep repeating
Taken from previous-year papers. If a pattern is marked "very common", expect to see it in your exam.
Memory unit conversion
very common"How many MB are there in 2 GB?" or "bits in a byte".
Go up or down the ladder: bit, byte, KB, MB, GB, TB.
Each step is ×1024 (not 1000).
How many MB are there in 2 GB?
1 GB = 1024 MB
2 GB = 2 × 1024
= 2048
Answer: 2048 MB
Binary, decimal, hex, octal conversion
very common"Binary equivalent of 45" or "decimal value of (1101)₂".
To binary: divide by 2 again and again, read remainders bottom to top.
Always check by converting back.
What is the binary equivalent of decimal 45?
45 ÷ 2 = 22 r 1, 22 ÷ 2 = 11 r 0, 11 ÷ 2 = 5 r 1
5 ÷ 2 = 2 r 1, 2 ÷ 2 = 1 r 0, 1 ÷ 2 = 0 r 1
Remainders bottom to top: 101101
Check: 32 + 8 + 4 + 1 = 45, so (101101)₂
Volatile memory and ROM types
common"Which memory is volatile?" or "EPROM is erased by ___".
Volatile = lost when power goes off (RAM, cache, registers).
ROM order: PROM (once) → EPROM (UV light) → EEPROM (electric).
EPROM can be erased by:
PROM can be written only once
EPROM is erased using a special light
EEPROM is erased electrically
Answer: Ultraviolet light
Which port for which device
common"Which port connects to a wired network?" or "which port carries audio and video?"
Learn one job per port: HDMI = video + audio, VGA = video only.
Ethernet (RJ-45) = network cable. USB = most devices.
Which port connects a computer to a wired LAN?
LAN means a network cable
The cable has an RJ-45 plug
It fits the Ethernet port
Answer: Ethernet (RJ-45) port
Impact and non-impact printers
common"Which of these is an impact printer?"
Impact printers hit the paper (dot matrix, daisy wheel).
Laser, inkjet and thermal never hit.
Which is an impact printer: Laser, Inkjet, Dot matrix, Thermal?
Impact means it strikes the paper
Dot matrix pins strike the ribbon
Laser and inkjet spray or print without a hit
Answer: Dot matrix
Input and output devices
common"Which is an input device?" or "soft copy vs hard copy".
Data going into the computer = input (keyboard, mouse, scanner).
Results coming out = output (monitor, printer).
A printout on paper is called a:
Screen display = soft copy (not permanent)
Paper printout is permanent
Permanent paper output is called
Answer: Hard copy
Storage devices and capacity
common"How much does a DVD / Blu-ray store?" or "which storage has no moving parts?"
Learn the sizes: CD 700 MB, DVD 4.7 GB, Blu-ray 25 GB.
SSD and pen drive = flash, no moving parts.
A single-layer Blu-ray disc stores about:
CD = 700 MB
DVD = 4.7 GB
Blu-ray uses a blue-violet laser and stores more
Answer: 25 GB