In this section we examined the various physical components that drive a computer. We covered this section over two class sessions; in the first half, we examined different boards in the body of the computer, and in the second half, we went over various cables, modern and obsolete, that have evolved over the course of nearly 30 years.
What makes a desktop computer what it is? And how does it stand out from other devices, such as phones, tablets, and the newly emerging devices such as smartwaches and smart TVs? Well, the answer is simple: a PC as we know it today, unlike the other devices, has undergone an evolution lasting well over 30 years, arising with newer types of boards, chips, and cards.
Over 70 years ago we saw our first digital computer, the ENIAC, an artillery trajectory calculator built for the United States Army during World War II. Its interface was as impressive as an array of lights and switches. It used a series of vacuum tubes used to conduct and regulate electron currents and was programmed by connecting wires into different ports located in a grid across the front of the machine. The machine spanned across a 30x50 foot room. This machine was limited to running one program at a given time and was capable of performing arithmetic calculations such as addition, subtraction, multiplication, division, and square root calculation.
In the 1960s arose the solid-state transistor, a major milestone in data processing that rendered diodes and vacuum tubes obsolete. The transistor is still in use today, enabling the ongoing battle between Intel and AMD in terms of performance quality (especially when dealing with performance factors in gaming). In that same decade came the BASIC language, which Microsoft had later purchased and used to create MS-DOS in the early 1980s. The idea here is that transistors were far easier to program than the classic analog-digital mainframes that remained dominant between the 1940s and 1950s, and with this new advancement emerged the development of more complex computer components that enabled computers to do more things, such as display high resolution images, play sounds, render videos, and eventually connect to the Internet so you can watch high resolution videos of goats wailing like humans.
Random access memory (RAM). Why do we care about the computer's evolution? Certainly, what is put into a computer -- the powerful specs and features -- are taken for granted and pushed to their limits as they are used. Think about it -- how would we be able to play Hitman, Far Cry, or Grand Theft Auto V on a system rocking a 2GB RAM? You'd be lucky to be able to play those games with only some lag; to be able to run an application using a high-definition, high-framerate game and physics engine (like Unity, which is a RAM hog all its own), you may need a computer running at least 8GB RAM.
Games are not the only reason we take advantage of our hardware, with a tendency to redline the specifications it may carry. But what is RAM? RAM stands for "Random Access Memory". It stores all the short-term variables created by all software, including the operating system itself (i.e. Windows, Mac OS, or Linux), running on the computer. It retains electronically stored data until the system has shut down, meaning the RAM requires that there must be a constant, adequate electronic current flowing throughout it in order to retain data.
Persistent storage. RAM can be easily contrasted with persistent storage devices, such as hard drive disks (HDDs), which contain a stack of spinning glass and aluminum platters and a magnetic read-write head that moves toward and away from the pivot (center) of the rotating platters. The fact that it has moving parts can make this medium cumbersome and more likely to fail due to wear-and-tear damage. In contrast, a more modern, improved (and more expensive) medium of persistent storage can be accomplished using solid-state drives (SSDs), which have no moving parts and use semiconductors in lieu of magnetic media to store data -- the device being solid-state (non-moving) can help to boost read-write performance at least twofold. Most importantly, however, these media store data beyond the supply of power; in other words, even after the computer is shut down, HDDs/SSDs continue to retain data stored onto them.
Audio and video. Computers, whether in the form of PCs, game consoles, or synthesizers, have evolved over the 1970s and 1980s to synthesize music in the form of MIDIs, which are digitized waveform sounds which can be used for applications as simple as beeping tones or as complicated as a Beethoven symphony. Likewise, computers have been, for over 40 years, able to produce graphical images that can be clicked, dragged, and manipulated with a mouse. All this is achieved using specialized hardware, known creatively as sound and video cards. These cards are memory chips all on their own, capacious of only several megabytes of digital AV data and, like RAM, clears out once the computer is no longer supplied power.
Here is a brief overview of the various cables that have evolved over the past several decades, as seen in class.