2.2: Tour of a Digital Device

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Page ID: 9753

Ly-Huong T. Pham, Tejal Desai-Naik, Laurie Hammond, & Wael Abdeljabbar
ASCCC Open Educational Resources Initiative (OERI)

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We will begin with the personal computers, which consist of the same basic components:

Motherboard (circuit board)
Central Processing Unit ( CPU)
Random Access Memory (RAM)
Video Card
Power Supply
Hard Drive (HDD)
Solid-State Drive (SSD)
Optical Drive (DVD/CD drive)
Card Reader (SD/SDHC, CF, etc.)

It also turns out that almost every digital device uses the same set of components, so examining the personal computer will give us insight into the structure of various digital devices. So let’s take a “tour” of a personal computer and see what makes them function.

Processing Data: The CPU

As stated in the previous section, most computing devices have a similar architecture. The core of this architecture is the central processing unit or CPU. The CPU can be thought of as the “brain” of the device or main processor. Back in the day, the CPU was made up of hundreds of wires that carried information.

An example of a personal computer on a desk. OK — Figure \(\PageIndex{1}\): Personal Computer by Green Chameleon on Unsplash is licensed under CC BY-SA 2.0

These wires carried out the commands sent to it by the software and returned results to be acted upon. The earliest CPUs were large circuit boards with limited functionality. Today, a CPU is generally on one chip and can perform a large variety of functions. There are two primary manufacturers of CPUs for personal computers: Intel and Advanced Micro Devices (AMD).

The speed (“clock time”) of a CPU regulates the rate of instruction and executes and synchronizes the various computer components. The faster the clock, the quicker the CPU can execute instruction per second. The clock is measured in hertz. A hertz is defined as one cycle per second. Using the binary prefixes mentioned above, we can see that a kilohertz (abbreviated kHz) is one thousand cycles per second, a megahertz (MHz) is one million cycles per second, and a gigahertz (GHz) is one billion cycles per second. The CPU’s processing power increases at an amazing rate (see the sidebar about Moore’s Law). Besides a faster clock time, many CPU chips now contain multiple processors per chip.

A multi-core processor is a single integrated circuit that contains multiple chips. These chips are commonly known as cores. The multi-core runs and reads instructions on the cores at the same time, increasing the speed. A computer with two processors is known as dual-core, or quad-core (four processors), increasing the processing power of a computer by providing multiple CPUs' capability.

When computers are running with multiple cores, additional heat is generated; this is why companies build in fans on top of the CPU. Macs have built-in a fail-safe that the computer will shut itself down to avoid damage when the temperature builds too rapidly. Smartphones avail themselves to hot temperatures. As our devices get smaller, we have many parts placed in a compact area, and in turn, devices will generate more heat. Running many apps on your phone simultaneously is another way to increase the phone's heat; this is why it is important to close applications after use.

Figure \(\PageIndex{2}\): (a) Bottom view of an Intel central processing unit Core i7 Skylake type core, model 6700K. LGA 1151 socket, 14 nm process, core frequency 4.00 GHz. Manufactured in Vietnam. Image by Eric Gaba is licensed under CC BY-SA. (b) Top view of an Intel central processing unit Core i7 Skylake type core, model 6700K. LGA 1151 socket, 14 nm process, core frequency 4.00 GHz. Manufactured in Vietnam. Image by Eric Gaba is licensed under CC BY-SA

Graphics processing unit (GPU) is an electronic circuit designed to rapidly manipulate and alter memory to accelerate the creation of images in a frame buffer for output. Devices that use GPUs are personal computers, smartphones, and game consoles. Nvidia is one of the powerhouse companies that manufacture HD graphics cards. Nvidia has been a leader in GPU’s chips, one of the most popular chips is the Nvidia GeForce, which is integrated with laptops, PCs, and virtual reality processors. Nvidia has also worked with many companies expanding its GPU chip market. Some notable companies that Nvidia works with are Tesla, Quadro, and GRID.