CompTIA Tech+ (FC0-U71): Computing Devices, Internal Components and Storage Types

Each portable device is built around one main job, and the right choice is the device whose design fits that job. A smartphone is a pocket computer with a cellular connection for calls, messaging, apps, a camera and GPS. A tablet has a larger touch screen for browsing, video, drawing and light work, but usually no built-in keyboard. An e-reader does one thing well: it shows books on an E Ink (electronic paper) screen that reflects light like paper, so it reads comfortably in sunlight, causes little glare and draws power mainly when the page changes, which gives battery life measured in weeks. A laptop is a full computer in a folding case, with a built-in keyboard and touchpad, running a desktop operating system and full desktop applications.

When a scenario lists requirements, match each requirement to the design feature in the table that delivers it, and check the trade-off column for the one that rules a device out.

A workstation is a high-performance computer used by one person at a desk for demanding work such as video editing, 3D modelling, engineering or data analysis. It typically has a powerful multi-core CPU, a lot of RAM, a dedicated GPU and fast storage. A server is a computer whose job is to provide services to many other computers (its clients) over a network: sharing files, hosting websites or email, running databases or printing. Servers are usually built for reliability — redundant power supplies and drives, remote management — and often sit in a rack with no one working at them directly.

The difference is the role, not the raw power: a machine counts as a workstation or a server by who uses it and how (one person at the keyboard versus many clients over the network), whatever its specification. A gaming console is a specialised computer for playing games and streaming media on a TV. It has a strong GPU but runs a closed platform: you install the manufacturer's approved games and apps, not general desktop software.

Virtual reality (VR) replaces what the user sees with a fully simulated world; augmented reality (AR) keeps the real world in view and overlays digital objects on top of it. A VR system uses a closed headset with motion tracking and controllers, so the room disappears — useful for simulators (a training cockpit), immersive games and virtual tours. An AR system uses a phone or tablet camera, smart glasses or a see-through headset, so digital content appears on a live view of the real surroundings — navigation arrows on the street, furniture previewed in your living room, repair instructions over a machine.

The deciding question is simple: can the user still see the real room? If not, it is VR; if yes, with digital additions, it is AR.

The Internet of Things (IoT) is the set of everyday physical objects that contain sensors, a small computer and a network connection, so they can report data and be controlled remotely, usually from a phone app. Home automation devices are IoT devices that run parts of a home automatically or on command. Know what each listed device does:

• Smart thermostat — controls heating and cooling on a schedule, can learn routines or sense that the house is empty and adjust the temperature, and can be changed from a phone.
• Video doorbell — a doorbell with a camera, microphone and speaker; it alerts your phone when someone presses it or moves nearby and lets you see and talk to the visitor from anywhere.
• Smart deadbolt / door lock — locks and unlocks by app, keypad code or schedule, can issue temporary codes and logs who entered. It controls access; it does not show you who is outside.
• Security system — connected cameras, door/window and motion sensors, and alarms that notify you or a monitoring service.
• Home assistant — a smart speaker or display with a voice assistant that answers questions and acts as a hub, controlling other smart devices by voice.
• Home appliances — refrigerators, washers, ovens and robot vacuums that can be monitored, scheduled or alerted from an app.
• Vehicles — connected cars with infotainment, GPS navigation, telematics, phone integration and over-the-air software updates.

When a scenario names a need, choose the device whose own sensors or controls perform that job; a hub or voice assistant coordinates other devices but cannot sense or act where it has no hardware of its own. Because IoT devices are networked computers, they also need their default passwords changed and their firmware kept up to date.

The motherboard (system board) is the main circuit board of a computer: the CPU sits in its socket, memory modules go in its RAM slots, drives connect to its storage connectors and expansion cards plug into its slots, and its circuits let all of them communicate. The power supply feeds power to it and the case (chassis) holds it, but neither connects components to each other.

Firmware is software stored on a chip on the motherboard. The classic firmware is the BIOS (basic input/output system); modern PCs use its successor, UEFI, which does the same job with more features (graphical setup screens, Secure Boot, support for very large boot drives). The firmware runs first when the computer is switched on, before any operating system:

1. It runs the power-on self-test (POST), checking that the CPU, memory and other key hardware work.
2. It initialises the hardware.
3. It follows the boot order to find a drive with an operating system (internal SSD, USB stick, network) and hands control to it.

Settings such as boot order, the system clock and enabling or disabling onboard devices are changed in the BIOS/UEFI setup screen, reached by a key during start-up. Anything that runs inside the operating system — utilities, drivers or other applications — only starts after the firmware has already chosen a boot device and loaded the OS, so start-up behaviour is controlled from the firmware, not from the OS.

The central processing unit (CPU) executes program instructions and performs the general-purpose calculations for everything the computer does. The graphics processing unit (GPU) is a processor specialised in rendering images, video and 3D scenes; it has many (often thousands of) small cores that do many simple calculations in parallel, which also makes it useful for AI and scientific work. Random-access memory (RAM) is the working memory: it holds the operating system, the programs that are running and the files that are open, so the CPU can reach them quickly.

A larger drive gives more space to store files but does not add working memory, so free drive space does not fix a computer that slows when many programs run at once. Match the upgrade to the symptom rather than picking the most powerful-sounding part.

A network interface card (NIC) is the component that connects a computer to a network. A wired NIC uses an Ethernet cable; a wireless NIC uses Wi-Fi radio. Wired Ethernet gives the most stable, lowest-latency connection because it does not share airtime or suffer interference and signal loss through walls; wireless gives mobility and needs no cable.

Components can be onboard (integrated into the motherboard or CPU) or added as an expansion card that plugs into a motherboard slot, usually PCI Express (PCIe). Most motherboards include an onboard Ethernet NIC and onboard audio, and provide video ports for the CPU's integrated graphics when the CPU has them. An expansion card adds a function the board lacks, upgrades it (a faster NIC, a Wi-Fi card, a dedicated GPU) or replaces an onboard function that has failed — a broken onboard Ethernet port can be replaced by a NIC expansion card without changing the motherboard. Software fixes help with software faults; when the hardware itself has failed, the hardware has to be replaced or bypassed.

A common mistake when adding a dedicated graphics card: the monitor must be connected to the card's video ports. If the cable stays in the motherboard's video port, the computer keeps using the onboard graphics and the new card does nothing for the display.

Volatile memory loses its contents when power is removed; non-volatile storage keeps them. RAM is volatile: anything typed but not saved lives only in RAM, so a power cut loses it. Saving writes the data to non-volatile storage such as an SSD, HDD or flash drive.

Read-only memory (ROM) is non-volatile memory that holds instructions which rarely or never change, such as a device's firmware; normal use only reads it. In modern computers the firmware chip is usually rewritable flash so the manufacturer can issue updates, but in everyday operation it behaves as read-only. The two properties can be combined deliberately: data that must disappear when power is removed belongs in volatile memory, while instructions that must not change belong in non-volatile, read-only storage. A network router, for example, runs from firmware it reads at start-up, while its live routing tables sit in RAM and are rebuilt after every restart.

Local storage is storage attached directly to the device, inside it or plugged into it. A hard disk drive (HDD) records data magnetically on spinning platters read and written by a moving head: it is the cheapest per gigabyte for large capacities, but slower and more fragile because of its moving parts. A solid-state drive (SSD) stores data in flash memory chips with no moving parts, so it is much faster, silent and more shock-resistant. NVMe (Non-Volatile Memory Express) SSDs talk to the CPU over the PCIe bus rather than the older SATA interface, which makes them the fastest common drives. M.2 is a small card-shaped form factor; an M.2 slot may support SATA, NVMe or both, so the drive type — not the slot shape — decides the speed.

Optical discs (CD, DVD, Blu-ray) are written and read by laser and need an optical drive, which many modern computers no longer have; they hold relatively little and are used for distribution and archives. External flash drives (USB sticks) are small, rewritable, need no network and plug into a USB port, which makes them the simplest way to carry files between computers that are not connected to a network.

Network storage is storage reached over a network instead of being attached to the device using it: a NAS or file server on the local network, or a cloud service over the internet. Local network storage lives on the home or office network, where every device on that network can reach it. A network-attached storage (NAS) device is a small appliance full of drives with its own simple operating system, managed through a web page; it shares files to phones and computers, keeps working when the internet is down, and stays available even when any one computer is switched off. A file server is a general-purpose server running a full server operating system that shares files, with more control (user accounts, permissions, other services) but more to set up and maintain. A cloud storage service keeps data in a provider's data centres, reachable from anywhere with an internet connection; the provider maintains the hardware, and the data survives a fire or theft at your site, but it depends on internet access and is not kept on your premises.

Real choices combine two decisions: where the data lives and which drives hold it. Settle the location from the hard constraints first (must the data stay on the premises, must it survive a site disaster, who will maintain it), then choose drives by how the data is used: HDDs for capacity at low cost, SSDs where speed matters more than price per gigabyte.