Computer cooling in the context of Hard disk drive

A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with other high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature.

A heat sink is designed to maximize its surface area in contact with the cooling medium surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface treatment are factors that affect the performance of a heat sink. Heat sink attachment methods and thermal interface materials also affect the die temperature of the integrated circuit. Thermal adhesive or thermal paste improve the heat sink's performance by filling air gaps between the heat sink and the heat spreader on the device. A heat sink is usually made out of a material with a high thermal conductivity, such as aluminium or copper.

A computer case, also known as a computer chassis, is the enclosure that contains most of the hardware of a personal computer. The components housed inside the case (such as the CPU, motherboard, memory, mass storage devices, power supply unit and various expansion cards) are referred as the internal hardware, while hardware outside the case (typically cable-linked or plug-and-play devices such as the display, speakers, keyboard, mouse and USB flash drives) are known as peripherals.

Conventional computer cases are fully enclosed, with small holes (mostly in the back panel) that allow ventilation and cutout openings that provide access to plugs/sockets (back) and removable media drive bays (front). The structural frame (chassis) of a case is usually constructed from rigid metals such as steel (often SECC — steel, electrogalvanized, cold-rolled, coil) and aluminium alloy, with hardpoints and through holes for mounting internal hardware, case fans/coolers and for organizing cable management. The external case panels, at least one of which are removable, cover the chassis from the front, sides and top to shield the internal components from physical intrusion and dust collection, and are typically made from painted metallic and/or plastic material, while other materials such as mesh, tempered glass, acrylic, wood and even Lego bricks have appeared in many modern commercial or home-built cases. In recent years, open frame or open air cases that are only partly enclosed (with freer ventilation and thus theoretically better cooling) have become available in the premium gaming PC market.

In personal computing, a tower unit, or simply a tower, is a form factor of desktop computer case whose height is much greater than its width, thus having the appearance of an upstanding tower block, as opposed to a traditional "pizza box" computer case whose width is greater than its height and appears lying flat.

Compared to a pizza box case, the tower tends to be larger and offers more potential for internal volume for the same desk area occupied, and therefore allows more hardware installation and theoretically better airflow for cooling. Multiple size subclasses of the tower form factor have been established to differentiate their varying sizes, including full-tower, mid-tower, midi-tower, mini-tower, and deskside; these classifications are however nebulously defined and inconsistently applied by different manufacturers.