Overview
IT Concepts and Terminology is 13% of the CompTIA Tech+ exam and covers four objectives: the input, processing, output and storage cycle; notational systems (binary, decimal, hexadecimal and octal); units of measure for storage, throughput and processing speed; and CompTIA's troubleshooting methodology. The content is small, but it is precise: a question either expects you to convert 11111111 to 255 or to know that a 1 Gbps link moves bits, not bytes.
The domain exists because the rest of the exam is written in this language. Infrastructure questions quote drive capacities in TB and Wi-Fi speeds in Mbps, Software Development Concepts relies on knowing what a bit and a byte hold, and Security scenarios about a broken device still expect you to identify the problem before you change anything. Learn the conversions and the six troubleshooting steps cold, and many later questions become simple lookups.
How it's tested
Questions are short and mostly single-answer multiple choice. Expect direct identification (which value is hexadecimal), conversions between number systems or units, ordering items from smallest to largest, and troubleshooting scenarios that ask what a technician should do FIRST or NEXT. Read every unit label, because a lowercase b versus an uppercase B changes the answer.
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Convert or identify the notation
You are given a value such as 0x1F or 1010 and asked for its decimal equivalent or which number system it belongs to. Prefixes, allowed digits and place values decide it.
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Units and magnitudes
You compare or order capacities and speeds (MB vs. GB, Mbps vs. Gbps, MHz vs. GHz) or estimate a transfer time, which requires converting bytes to bits.
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Troubleshooting step order
A scenario stops mid-process and asks for the next step. The answer is the step that follows the last completed one in CompTIA's six-step sequence, not the most tempting fix.
A user reports that a printer stopped working. The technician has questioned the user and learned a new driver was installed yesterday, then suspects the driver. What is NEXT? The last completed step is establishing a theory of probable cause, so the next step is to test that theory, for example by rolling back the driver and printing a test page, before planning a permanent fix or documenting anything.
Objectives 4
Official objectives from the CompTIA outline, in outline order.
1.1 Explain the basics of computing.The input, processing, output and storage (IPOS) cycle.
- What it means
- Every computing task follows the same loop: data comes in through an input device, the CPU processes it, results go to an output device, and anything that must survive is written to storage.
- What to understand
- Classify devices and actions by role in the cycle: a keyboard or microphone is input, the CPU performs processing, a monitor or printer is output, and saving a file to an SSD is storage. Some devices, such as a touchscreen or a multifunction printer, play more than one role.
- How it shows up
- A question describes an everyday action, such as scanning a receipt and saving it as a PDF, and asks which step of the cycle a specific part of that action represents.
- Common confusion
- Candidates call RAM storage in the IPOS sense. RAM holds data while it is being processed and loses it at power-off; the storage step means writing data somewhere persistent.
1.2 Identify notational systems.Binary, decimal, hexadecimal and octal: digits, bases and conversions.
- What it means
- Binary is base 2 (digits 0-1), octal base 8 (0-7), decimal base 10 (0-9) and hexadecimal base 16 (0-9 then A-F). The same quantity can be written in each: decimal 255 is 11111111 in binary, FF in hex and 377 in octal.
- What to understand
- Know the place values of an 8-bit binary number (128, 64, 32, 16, 8, 4, 2, 1) so you can convert in either direction, and that one hex digit stands for exactly four bits while one octal digit stands for three. Hex is often marked with a 0x prefix and appears in MAC addresses and color codes.
- How it shows up
- You are shown a value like 0x2A, 1101 or 1F4 and asked to identify the system or give its decimal value, or you pick which system a MAC address such as 00:1A:2B:3C:4D:5E is written in.
- Common confusion
- A string of 1s and 0s is not automatically binary; 1010 could be decimal one thousand and ten. Look for context or a prefix, and remember that any digit 8 or 9 rules out octal and any letter A-F points to hex.
1.3 Compare and contrast common units of measure.Storage in bytes, throughput in bits per second, processing speed in hertz.
- What it means
- Storage capacity is counted in bytes (KB, MB, GB, TB, PB), data transfer rate in bits per second (bps, Kbps, Mbps, Gbps, Tbps), and CPU clock speed in cycles per second (MHz, GHz). A byte is eight bits.
- What to understand
- Each prefix step is about a thousand times larger (1,000 in decimal or 1,024 in binary counting), so order matters more than the exact multiplier. To relate a file size to a connection speed, multiply bytes by 8 to get bits: 100 Mbps moves roughly 12.5 MB per second before overhead.
- How it shows up
- A scenario gives a file size in MB or GB and a connection speed in Mbps and asks for an approximate transfer time, or lists capacities and speeds to order from smallest to largest.
- Common confusion
- Candidates treat MB and Mb as the same unit and come out eight times too fast. A lowercase b means bits and an uppercase B means bytes.
1.4 Explain the troubleshooting methodology.CompTIA's six-step method from identifying the problem to documenting it.
- What it means
- The steps are: identify the problem; establish a theory of probable cause (question the obvious, research the knowledge base or internet); test the theory; establish a plan of action and implement the solution; verify full system functionality and implement preventive measures; and document findings, lessons learned, actions and outcomes.
- What to understand
- Identifying the problem means gathering information, questioning users, reproducing the issue and asking what changed recently. If a test disproves the theory, you form a new theory or escalate; you do not start implementing. Documentation comes last but is never optional.
- How it shows up
- A scenario names what the technician has already done and asks what to do NEXT, or asks which step a specific action (such as checking whether the cable is plugged in) belongs to.
- Common confusion
- Candidates put verification after documentation or skip testing the theory. Verify full functionality first, then document what was found and done.
High-yield concepts
The terms, rules and formulas this domain turns into questions most often.
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IPOS cycle
Input brings data in, processing transforms it in the CPU, output presents the result, and storage keeps it for later.
- Remember
- Storage in this model means persistent saving (SSD, HDD, cloud), not RAM, which only holds data while it is being worked on.
- Tested as
- Tested by asking which stage a device or an action represents in a short everyday scenario.
- Trap
- Labelling a dual-role device such as a touchscreen as only input or only output, when it does both.
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Binary place values
Each binary position doubles the one to its right: 1, 2, 4, 8, 16, 32, 64, 128 for an 8-bit byte, so 10110 is 16 + 4 + 2 = 22.
- Remember
- Eight bits of all 1s equal 255, so one byte can hold 256 distinct values (0 to 255).
- Tested as
- Binary-to-decimal and decimal-to-binary conversions are the most common calculation in this domain.
- Trap
- Reading the bits from left to right with the smallest value first, which reverses the result.
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Hexadecimal
Base 16 uses 0-9 and A-F, where A is 10 and F is 15; each hex digit represents exactly four bits, so two hex digits describe one byte.
- Remember
- 0x in front of a value marks hex, and FF equals 255 decimal and 11111111 binary.
- Tested as
- Appears in MAC addresses, memory addresses and web color codes, and in direct conversion questions.
- Trap
- Treating a hex value without letters, such as 0x10, as decimal ten; it is sixteen.
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Octal
Base 8 uses digits 0-7, and each octal digit maps to three bits, so 755 is 111 101 101 in binary.
- Remember
- Any digit 8 or 9 means the value cannot be octal.
- Tested as
- Usually tested by identification or a small conversion alongside the other three systems.
- Trap
- Confusing octal (base 8) with an eight-bit byte; they are unrelated ideas.
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Bit vs. byte
A bit is a single 0 or 1; a byte is eight bits and is the basic unit for file size and storage capacity.
- Remember
- Lowercase b is bits, uppercase B is bytes; network speeds are quoted in bits per second, storage in bytes.
- Tested as
- Every transfer-time question hinges on converting between the two by a factor of eight.
- Trap
- Dividing a file size in MB by a speed in Mbps without multiplying by eight first.
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Storage unit ladder
KB, MB, GB, TB and PB each step up by roughly a thousand, so a petabyte is about a million gigabytes.
- Remember
- Drive makers count in powers of 1,000, while many operating systems report in powers of 1,024, which is why a 1 TB drive shows about 931 GB.
- Tested as
- Ordering capacities and picking a sensible size for a described need (a photo, a movie, a data center archive).
- Trap
- Assuming a drive is faulty or short-changed because the OS reports less than the label.
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Throughput units
bps, Kbps, Mbps, Gbps and Tbps measure how many bits move per second across a link.
- Remember
- 1 Gbps equals 1,000 Mbps, and dividing by 8 gives approximate bytes per second, so 1 Gbps is about 125 MB/s.
- Tested as
- Used to compare internet services, Ethernet links and Wi-Fi standards, and in transfer-time math.
- Trap
- Expecting advertised throughput to be achieved in practice; overhead and interference always reduce it.
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Clock speed (MHz, GHz)
Hertz counts cycles per second; a 3.2 GHz CPU's clock ticks 3.2 billion times per second.
- Remember
- 1 GHz = 1,000 MHz, and hertz measures processing speed, not storage or bandwidth.
- Tested as
- Appears when you must match a unit to what it measures or compare two processors' clock rates.
- Trap
- Concluding that a higher clock speed alone makes a computer faster, ignoring cores, RAM and storage speed.
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Question the obvious
Within establishing a theory, check simple causes first: power, cables, a switched-off Wi-Fi toggle, a muted speaker.
- Remember
- Simple causes are checked before complex ones, and research (knowledge base, vendor site, internet) belongs to the same step.
- Tested as
- Scenarios reward the technician who checks the cable or the power before replacing hardware or reinstalling software.
- Trap
- Choosing an expensive or disruptive fix as the first action because it sounds thorough.
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Verify full system functionality
After implementing a fix, confirm that the whole system works for the user, not only that the original symptom has disappeared, and add preventive measures.
- Remember
- Verification and preventive measures come before documentation, the final step.
- Tested as
- Tested through NEXT questions after a fix has just been applied.
- Trap
- Closing the ticket and documenting immediately after the fix without confirming the user can work normally.
Side by side
Concepts candidates mix up, compared on the point that decides the answer.
Binary vs. octal vs. decimal vs. hexadecimal
| Concept | Meaning | Key difference | Common trap |
|---|---|---|---|
| Binary (base 2) | Digits 0 and 1; place values double: 1, 2, 4, 8 and so on | The native language of hardware; eight digits make one byte | Assuming any number made of 1s and 0s must be binary |
| Octal (base 8) | Digits 0-7; place values 1, 8, 64 | Each digit equals three bits | Accepting a value containing 8 or 9 as octal |
| Decimal (base 10) | Digits 0-9; place values 1, 10, 100 | The human-friendly system used for answers and everyday counts | Forgetting to convert back to decimal when the question asks for it |
| Hexadecimal (base 16) | Digits 0-9 and A-F; place values 1, 16, 256 | Each digit equals four bits, so it compactly writes bytes and MAC addresses | Reading 0x10 as ten instead of sixteen |
Storage units vs. throughput units vs. processing speed
| Concept | Meaning | Key difference | Common trap |
|---|---|---|---|
| Storage (B, KB, MB, GB, TB, PB) | How much data a device or file holds, counted in bytes | A quantity at rest, with an uppercase B | Using it to describe an internet plan or link speed |
| Throughput (bps, Kbps, Mbps, Gbps, Tbps) | How many bits cross a connection each second | A rate over time, written with a lowercase b | Forgetting the factor of eight when comparing with file sizes |
| Processing speed (MHz, GHz) | How many clock cycles a processor completes each second | Describes CPU timing, not data quantity or network rate | Treating GHz as the sole measure of overall computer performance |
Exam traps
Each trap is an answer that looks right. Learn the clue that should change your mind.
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Ignoring the bits-to-bytes conversion
- What candidates pick
- A transfer time eight times shorter than reality, from dividing MB by Mbps directly.
- Why it looks right
- The numbers line up neatly and the prefixes match, so the division feels complete.
- Why it's wrong
- Megabytes and megabits differ by a factor of eight, so the file must be converted to bits before dividing by the line rate.
Clue to watch for Check the case of the b in each unit; a mix of MB and Mbps signals a multiply-by-eight step.
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Jumping straight to the solution
- What candidates pick
- Replacing hardware or reinstalling software as the first action in a troubleshooting scenario.
- Why it looks right
- It looks decisive and would probably fix the symptom.
- Why it's wrong
- CompTIA's method starts with identifying the problem: questioning the user, reproducing the issue and asking what changed. Acting first can destroy evidence or cause new problems.
Clue to watch for Words such as FIRST combined with a vague user complaint mean information gathering, not repair.
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Implementing an untested theory
- What candidates pick
- Creating a plan of action right after establishing a theory.
- Why it looks right
- The theory sounds convincing, especially if a recent change is mentioned.
- Why it's wrong
- The theory must be tested first; if the test fails, you form a new theory or escalate rather than proceed.
Clue to watch for If the scenario says the technician suspects or believes a cause, the next step is to test it.
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Documenting before verifying
- What candidates pick
- Recording the fix and closing the ticket right after applying it.
- Why it looks right
- Documentation is a familiar wrap-up task and the symptom appears gone.
- Why it's wrong
- Verification of full system functionality and preventive measures come before documentation, which is always the final step.
Clue to watch for The fix has just been applied and nothing says the user confirmed everything works.
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Misreading the base
- What candidates pick
- Treating 1010 or 0x12 as an ordinary decimal number.
- Why it looks right
- The digits look like familiar decimal values.
- Why it's wrong
- The base changes the quantity: binary 1010 is 10, and hex 12 is 18.
Clue to watch for A 0x prefix, letters A-F, or the question explicitly naming binary or hex.
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Equating clock speed with performance
- What candidates pick
- The computer with the highest GHz rating as the fastest overall machine.
- Why it looks right
- GHz is the most visible number on a spec sheet.
- Why it's wrong
- Clock speed is one factor; core count, RAM and storage type also shape real performance, and the question may be asking only which unit measures CPU speed.
Clue to watch for The scenario mentions slow file opening or multitasking, which points at storage or memory rather than clock rate.
Answer framework
Use these steps for any Domain 1 question, whether it is a conversion, a unit comparison or a troubleshooting order.
- Identify what is being measured or represented: a quantity of data, a transfer rate, a clock speed, or a number written in a particular base.
- Check every unit symbol and prefix, including the case of b versus B, and convert bytes to bits by multiplying by eight before comparing rates.
- For number systems, look for a 0x prefix, letters A-F or digits above 7, then convert using place values: powers of 2, 8 or 16.
- For troubleshooting, locate the last step the technician completed and choose the step that immediately follows it in the six-step order.
- Eliminate answers that skip a step, act on an untested theory, or describe a unit that measures something else.
Practice question
Want more like this? The CompTIA Tech+ practice test has questions for every domain.
Checklist
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Study strategy
Start with notational systems because they need the most practice. Write the binary place values 128 down to 1 from memory, then convert twenty random numbers each way between decimal, binary and hex until it takes under thirty seconds. Add octal last; it is the least common but the easiest to identify once you know its digits stop at 7.
Next, lock in units. Build a single table with storage prefixes, throughput prefixes and clock speeds, and practice transfer-time problems that force the bytes-to-bits conversion. Commonly underestimated: the case of the letter b, and the decimal-versus-binary capacity difference that explains why drives look smaller than advertised.
Then learn the six troubleshooting steps as a sequence, not a list. For each step, write one concrete action a technician would take, such as asking the user what changed or confirming a printer works from every application after a fix. Practice NEXT-step questions by covering the answer and naming the step that follows.
Finish with the IPOS cycle, which takes the least time. Afterwards, take timed practice questions mixing all four objectives, and carry the unit skills straight into Infrastructure, where storage types and network speeds use them constantly.
FAQ
How much of CompTIA Tech+ is IT Concepts and Terminology?
It is 13% of the exam, which works out to roughly nine questions if you apply the weight to the 70-question maximum. CompTIA does not publish per-domain counts, so treat that as a planning estimate.
Do I need a calculator for binary and hex conversions?
Plan to work without one. The values tested are small enough to convert with place values, and practicing by hand is faster than relying on a tool that may not be available.
Is a kilobyte 1,000 or 1,024 bytes?
Both conventions exist: decimal (1,000) is used by drive manufacturers and binary (1,024) by many operating systems. For exam questions, focus on the order of the units and the factor of eight between bits and bytes.
What are the six steps of the CompTIA troubleshooting methodology?
Identify the problem, establish a theory of probable cause, test the theory, establish a plan of action and implement the solution, verify full system functionality and implement preventive measures, then document findings, actions and outcomes.
What happens if the theory of probable cause is wrong?
You establish a new theory or escalate the issue. You do not move on to a plan of action until a theory has been confirmed by testing.
How hard is this domain compared with the others?
It is one of the most predictable domains because the answers are exact. The difficulty is precision under time pressure, so drill conversions and the step order until they are automatic.
How does this domain connect to the rest of Tech+?
Infrastructure uses the same units to compare storage, internet services and Wi-Fi, Software Development Concepts builds on bits and data types, and troubleshooting logic applies to scenarios in every domain.
Other IT Fundamentals & Hardware certifications
Where the same subject shows up in other exams. Cards marked "Same subject" open the matching domain.
Test your Domain 1 knowledge
You have worked through the computing cycle, number-system conversions, storage and throughput units, and the troubleshooting order. Check that you can do them quickly and accurately under timed conditions.
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