Week 2 of the Google I.T. Support Professional Certification course on Coursera.org is focused on the hardware used to create the modern computer. The modern computer is made of a few basic components, with some slight variations, that all serve to create a machine that will process data. That’s all a computer does.
One thing I have learned through my recent work experience as a computer repair tech is that hardware may look frightfully delicate and complex, but it is really pretty simple to work with. If you pay attention to what you are doing, have a little research or knowledge going, then you aren’t going to break anything—well, you’re not going to break too many things. It seems to me that the really delicate and dangerous thing is software. Most of the hardware repairs we do at work are straightforward. Most of the software things we come up against are painfully resistant to repair or improvement.
A modern computer will have what are called peripherals, such as a monitor, keyboard, mouse, speakers, etc., which are all connected to the system (and each other) through the motherboard. The motherboard is a printed circuit board (PCB) that has all the components needed to power on the computer and begin processing data. The actual processing is done in the central processing unit (CPU). The CPU is a silicon chip–and it’s a big one!–that essentially directs all the activity in the computer which is not directed by software or the user. It is the central nervous system, sort of.
It is very interesting how something so important to the modern computing experience is so little understood by almost everyone, myself certainly included. I guess it is due to the seeming complexity, or perhaps the vanishingly small scale of the parts in question, like the electrons flying around inside them, at least, that make most people shy away from even asking how a CPU works. And don’t get me wrong, asking is not going to help you understand very much. The short version, sufficient for this course, and most practical applications, is that electrons are stored in really tiny transistors to create and “on” or “off” state, and those make up what are known as logic gates, which create pathways for algorithmic processing. Actually, on second thought, let’s just say the CPU is the central nervous system.
Attached to that is the RAM, or random-access memory. This is the short-term memory of the system, where data is stored until it is needed. Much of the processing speed and power of modern computers is derived from the way the CPU can predict, store, call on and overwrite information in RAM.
Long-term memory, or storage, is performed by either a hard drive or a solid-state drive. They are mechanically different, but functionally they both act as a repository for information. (But only an SSD will change your life.) Unlike the “volatile” RAM, which is erased if powered off, storage media are “non-volatile,” meaning they (should!) preserve data after being powered off. This is a really convenient feature of modern computers, giving you the ability to pick up where you left off, instead of having to re-write all your software every time you turn your computer on. That would suck.
There were a couple of supplemental readings on storage and processors, which I dutifully read all the way through. After a short video about USB I have to admit I really skimmed over the supplemental reading on the history of USB and all the standards for performance and power delivery. I like connecting peripherals as much as the next guy, but jeez…
Throw it all into a case, add a power supply and maybe an optical drive and you have yourself a computer. After a painfully slow desktop build video (I recommend liberal use of the 1.5x playback option) there was a video about BIOS (Basic Input/Output System) and what it does before your operating system is loaded. Which leads us neatly into week 3, the operating system.
Before you can start week 3, though, the course has a fairly involved (but mercifully voluntary) project where you build a desktop computer and document all the steps with photos and written instructions. I suspect this process would take several hours to complete. But the kind souls at Google said that since it required purchasing hundreds of dollars worth of components it was a voluntary assignment.*