CompTIA A+ Core 1 (220-1101) cheat sheet
CompTIA
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At a glance
Format: Multiple choice, drag-and-drop, and performance-based
Domain weight map
Heaviest first - spend your time hereHow this exam thinks
Core 1 tests exact specifications and the correct first action, not general familiarity: the right port number, the right standard, the right troubleshooting step, in order.
Spot the trap
Tempting wrong answers, and why they failTempting but wrong
A sudden change in runtime always means the cell has reached its charge-cycle limit, so replace the battery straight away.
Why it fails
Tempting because an ageing cell is a real cause of drain, but swapping hardware before any diagnosis skips the identify-the-problem step, and the absolute claim that it is always the cell ignores common software causes.
Hardware and Network Troubleshooting
Tempting but wrong
RJ-11, the six-position plug, is fine for terminating a copper run feeding a desktop network adapter.
Why it fails
Tempting because RJ-11 looks like a smaller Ethernet plug and uses the same crimp tooling, but it is a six-position telephone connector and will not carry a Gigabit Ethernet link.
Hardware
Tempting but wrong
UDP opens a session with a three-way handshake and retransmits lost segments, while TCP just fires off datagrams with no acknowledgement.
Why it fails
The attributes are reversed. The handshake, acknowledgements, and retransmission belong to TCP, not UDP. UDP is the lightweight connectionless protocol that sends datagrams without acknowledgement.
Networking
Tempting but wrong
A DDR4 SODIMM uses 204 pins, the same as a laptop DDR3 module.
Why it fails
204 is a genuine SODIMM pin count, but it belongs to DDR3 SODIMM, not DDR4. DDR4 SODIMM is standardised at 260 pins, so 204 is the wrong generation.
Mobile Devices
Tempting but wrong
Is application virtualization the right way to safely detonate live malware samples?
Why it fails
No. App virtualization isolates one application from the host filesystem but still shares the host kernel, so it is not built to safely run live malware. A sandbox VM is the tool for containment.
Virtualization and Cloud Computing
Tempting but wrong
A failing wireless radio inside the one tablet keeps losing its association with the access point at random.
Why it fails
Tempting because a faulty client radio does cause intermittent drops, but every device in that room is affected equally, which rules out a fault confined to one tablet's hardware.
Hardware and Network Troubleshooting
Tempting but wrong
Cat 6 UTP supports high speeds and easily reaches the full 300 metre distance.
Why it fails
Tempting for its speed, but copper Ethernet is limited to roughly 100 metres per run, and unshielded pairs are still susceptible to the motor interference. It fails both requirements.
Hardware
Tempting but wrong
For an encrypted web session the browser connects to TCP port 80, the default for HTTP between browser and web server.
Why it fails
Port 80 is genuinely used for web traffic, but it carries plaintext HTTP with no TLS encryption, so it does not meet an encrypted requirement. The encrypted default is HTTPS on port 443.
Networking
Key terms
Exam-day rules
- Read the last line of the question first. It tells you what is actually being asked, so you can read the scenario looking for the answer rather than memorising every detail.
- For a problem scenario, choose the BEST or FIRST action, not any action that helps. Two options are often both valid; the exam wants the correct next step given the constraint in the stem.
- Check the exact number. A wrong port, a mispaired 802.11 band, or a wrong RAID minimum is the most common plant, so verify the specific figure in each option.
- Know the six troubleshooting steps in order cold. A distractor that swaps testing a theory with implementing a fix, or that skips verification or documentation, is the classic methodology trap.
- When data is at risk, back up before you rebuild. A degraded RAID array or a failing drive wants a backup first; an option that rebuilds or clones before securing the data is the unsafe trap.
Revision schedule
- Day 1Map the blueprint and set a date
- Weeks 1-2Drill the high-yield facts (Networking and Hardware)
- Week 2Cover mobile devices and virtualization and cloud
- Week 3Master the troubleshooting methodology
- Week 4Practise on scenarios with worked explanations