Layman's Guide to Computing

A hard disk consists of a read arm, and a set of magnetic platters which store data. To read or write data, the read arm must move to the appropriate track of the rotating platter, and detect the magnetic field (for reading), or attempt to magnetise the domains on the platter (for writing). Operations that require the read arm to access different parts of the magnetic platters intermittently result in slower read speeds.

Solid-state disks are much faster than hard disks because they have no moving parts, so no time is wasted waiting for parts to get into the right position. However, they are more expensive than hard disk drives.

Driver files provide information about the driver, and instructions on how to receive information from the device, and encode information to be passed to the device. The operating system may come with generic driver files for the device, but custom driver files might provide better performance or additional features.

3D models are represented with vertices (points), edges (line segments between points), and faces in a computer. Images known as textures can be mapped to faces to give the impression of detail.

Computers are general-purpose machines that usually process integer calculations. The graphics pipeline requires more specialised hardware that can process decimal number calculations. This is why high-performance graphics usually requires a graphics card.

Graphics cards contain lots of tiny cores that are much better at performing the same calculation for lots of decimal numbers. These cores are organised into compute units; a graphics card with more compute units can perform more calculations every second. Graphics cards have their own onboard memory, separate from the CPU. GPU memory is different from computer memory; it is configured for much higher data throughput. Integrated graphics are GPUs that are integrated into a CPU chip; these do not have their own onboard memory, and share memory with the CPU.

The VGA video format originated in the time of cathode-ray televisions (CRTs). It was superseded by HDMI, a video format standardised by consumer electronics companies. DisplayPort, on the other hand, is a video format standardised by computer display companies.

Analog formats such as VGA mostly contain the control signals that the CRT needs to operate, while digital formats such as HDMI and DisplayPort contain image data that the device must convert to control signals. Analog signals need a digital-analog-conversion (DAC) chip to be converted to digital signals, hence VGA-HDMI adapters tend to be more costly than DisplayPort-HDMI adapters. Dedicated graphics cards generally support more simultaneous output video streams than integrated graphics cards.

USB is a (licensed) technical standard that describes how devices connect to each other through a cable. USB Type-C is a new connector standard that supports USB 3, DisplayPort, HDMI, and Thunderbolt. It is able to carry multiple types of data simultaneously, in limited combinations. In a USB connection, one device acts as the host while the other acts as the device; the host initiates all communication.

USB Power Delivery is a specification that describes how much voltage and current can be supplied by different categories of USB cables. It allows power delivery at different levels for all kinds of connected devices, up to 100W. This should help to simplify cable setups that otherwise require multiple kinds of cables between two closely interconnected devices (such as a laptop and an external monitor).

Upgradable parts need a slot or socket to be inserted into; these slots/sockets need to be made robust enough, causing them to take up more space than a soldered part. Devices which were designed to be small and portable generally eliminate these as far as possible, opting to have parts directly soldered to the board instead.

The larger the surface area, the faster an object loses heat. The larger the temperature difference between object and surroundings, the faster the object loses heat. Heat is bad for computers, and CPUs will need cooling to be able to process computations quickly. A mobile phone thus typically uses no more than 4 W of power, a laptop can use 25–45 W, and a desktop can usually use 65 W and more. Two popular ways of increasing the cooling capacity of a device is to attach a larger piece of metal to the chip (passive cooling), or use a fan to force air over the heatsink (active cooling).

AC power from the wall uses electric current that alternates directions, while DC power from batteries uses electric current that flows in one direction only. All electronics are DC-only, and require an AC-DC adapter to be powered from the wall. The AC-DC conversion produces a significant amount of heat; AC-DC adapters are usually external unless the device has sufficient space or cooling capacity for it.