Beginner's Guide to the PC

If you are a new PC user, or would like to understand how your PC works, this article is for you! PCs can be intimidating, but they can save us time, make us more productive, and give us new hobbies. The intent of this article is to explain the PC in easy-to-understand terms. We will focus on the desktop PC, but most of the information will still make sense if you own a laptop.

To keep it simple, we will define a PC as not only the "system unit" that does most of the work, but the other pieces of hardware that are required: the monitor (or video display), keyboard, mouse, and printer.

The Monitor

The monitor is the easiest part of the PC to understand. It looks like a television screen and its purpose is similar - to provide video output. Whenever you do anything on the PC you will be looking at the monitor. There are 2 types of monitors:

  • The CRT (cathode ray tube): This monitor is older technology, inexpensive, and reliable. It is compatible with most PCs. However, it's heavy, bulky, requires a great deal of space (especially depth), and generates a lot of heat. In addition, the CRT gives off radiation, which many think is harmful.
  • The Flat Panel monitor: This monitor is sleek, lightweight, fairly expensive, and, because of its shallow depth, can be positioned further back on the desktop. A good flat panel has adjustable height and screen tilt. The image produced is slightly less vivid than a CRT. If you can work it into your budget, buy a 19” flat panel monitor when you purchase a PC. If you are replacing a CRT, make sure you get a flat panel that will work with your existing PC.

The System Unit

The system unit consists of a lot of electronic components neatly arranged inside a plastic or metal case that lies on the desktop or sits upright on the floor. Inside the case is a power supply and fans to keep the unit cool. PCs generate a lot of heat when powered on; but even with the fans, care must be taken to always provide adequate air circulation so the components will not overheat.

Inside the system unit is a large circuit board to which all the other components are attached. It's called the "motherboard." The motherboard is like the nervous system of the system unit ... it connects all the components together and helps them talk to each other. Let's begin by discussing the “big three components:” the CPU, hard disk, and memory. To help you understand them, I’m going to create an analogy between these components and YOU working in your office.

Central Processing Unit

The CPU is the “brains” of the PC. It performs the calculations and coordinates the other components. The CPU is housed on a "microchip" - a very small wafer packed with electronic circuits. Using our analogy, the CPU is like your brain. And your brain controls your calculations and all of your components.

Hard Disk or Hard Drive

The hard disk is where your data is permanently stored; i.e. Word files, photos. Using our analogy, the hard disk is like the filing cabinet in your office. The hard disk consists of platters and various mechanics and electronics. Often a PC's hard drive is called the "C drive." (All the drives in a PC have a letter assigned to them.) In your filing cabinet are individual papers inside of folders. And you may have folders inside of folders. This is how the hard disk is structured. The smallest “piece of paper” the hard disk recognizes is a “file” - like a Word document. The hard disk stores its files in folders, and often has folders inside of folders. So, the PC’s hard drive is like your filing cabinet. The PC stores 3 basic kinds of information on its hard disk.

  • The Operating System (OS): The OS is a large program that operates the PC hardware - the most popular being Microsoft Windows. Without an OS, your PC is useless. The OS 'talks' to the hardware and interfaces between it, the user, and the application programs (see below). It receives input from the keyboard and mouse, sends information to the monitor, controls data going in and out of the CPU, and keeps track of files and folders on the hard disk. Typically when you buy a PC the OS is already on the hard disk and ready to run when you press the power button.
  • Application software: If the OS allows the PC to work, application programs allow YOU to work! An application is a software program, running on top of the OS, which performs specific functions - like word-processing. You may opt to purchase your PC with some application software already on the hard disk, or you can buy it separately. Most purchased software comes on a CD. Some application software can be downloaded for free, or for a minimal charge, from the Internet.
  • Your Data: the other information that is permanently stored on the hard drive is the data you create; i.e. Word documents, Excel spreadsheets, or photos you’ve loaded in from your digital camera.

Memory

Memory is the place that the CPU temporarily puts the data it is currently working on. You can’t get your work done in your office if your data sits in the file cabinet. You have to set it on your desk to work on it. The same is true for your PC. It can't work with the data sitting on the hard disk. It must take it out and put it into memory. Memory consists of many circuits residing on microchips. The more memory you have, the more programs you can have running at the same time and the faster your PC will run. Also, when your PC is running, key portions of the Operating System are also kept in memory.

Now let's talk about drives that read and write to media (i.e. CDs) that is removable. You need these drives for several reasons: to install software, to play CDs or DVDs, to backup your data, to copy files for someone else, or to create a music CD. We will discuss 3 other drives: the diskette drive, the CD drive, and the DVD drive. All 3 attach to the motherboard inside the system unit and you access them from the front of the case. Before you buy a PC, sit down with an expert and discuss how you are going to your needs so you will know what features these drives should have.

  • Diskette Drive: The diskette drive is always called the "A drive." A diskette is a 3 ½” square disc. It holds a small amount of data compared to CDs and DVDs. Few new PCs have diskette drives today. However, if you have lots of data stored on diskettes, you can request that one be installed in your new PC. NOTE: Don’t leave a diskette in the drive when you power down your PC. If you do, you'll get the error message “non-system disk or disk error” when you power on your PC and you will think your PC is broken. Just take the diskette out of the drive and press any key on the keyboard to resume.
  • CD drive: CD stands for compact disc. (On my PC it's the "D" drive). Your CD drive will either just read CDs, or read and write to CDs. When data is written to a CD, a laser “burns” the data onto its surface.
  • DVD drive: DVD stands for digital video disc. A DVD looks like a CD, but it holds a lot more data and the recording format is different. New PCs usually come with a DVD reader. (Mine is the "E" drive.) You can opt for a DVD drive that reads and writes. I recommend upgrading your DVD drive to a “burner” if you have large amounts of data (photos, perhaps) to backup on a regular basis.

Lastly, there are some other components inside the system unit that we will mention briefly. These components all have ports on the back of the system unit. They control the components that allow you to access the Internet, along with all of the peripheral devices.

  • The modem and/or Ethernet network card: To access the internet via dial-up, you will plug your phone line cord into a modem port on the back of the system unit. You will use the Ethernet network card if you are setting up a home network or attaching the PC to the internet via a broadband connection (cable or DSL). The different network devices that could plug into the network card port are beyond the scope of this article.
  • Also inside the system unit and attached to the mother board are the electronics that control your peripherals; such as the monitor, mouse, keyboard, speakers, and printers. If you look at the back panel of the system unit, you'll see a myriad of ports and connectors in which to attach these peripherals.

Let's quickly review! The monitor is like a TV and is where the video output is displayed. There are two types of monitors: CRTs and flat panel. The system unit houses the PC's internal components that are attached to, and managed by, the motherboard (large circuit board). The three largest components of the system unit are: the CPU (your brain), the hard disk (filing cabinet), and memory (working area on your desk). Three kinds of information are stored on the hard disk: the operating system (OS), application software, and your data. And we know the PC hardware is useless without the OS. In addition, there are other useful drives inside the system unit that read and write to removable media (diskettes, CDs, and DVDs).

Now let's talk about these peripherals. A peripheral is just an “external” device attached to the PC: monitor, keyboard, mouse, printer, scanner, etc. As mentioned above, thought they are external devices, there are electronic components attached to the mother board that control them. Let's go into a bit more detail.

  • Monitor: To get a warm and fuzzy start, we began this article talking about the monitor - the video output of our PC. To attach a monitor to the system unit, a video card is attached to the motherboard and helps manage the data being sent to the monitor. The other side of the video card is a port into which you attach the monitor cord. If you use a PC to do a lot of graphics or play video games, you need a powerful video card. For most of us, a modest video card will suffice.
  • Speakers: Most PCs come with speakers and the speakers are controlled by a sound card. The sound card is attached to the motherboard and has ports into which you attach the speakers and perhaps a microphone. Sound cards also vary in power and price.
  • Keyboard and mouse: We use these devices to enter data into to the PC. The motherboard has the necessary controllers to manage your keyboard and mouse. On the back panel you'll see round ports for attaching these devices. However, many keyboards and mice can be attached to the PC via a "USB port." (See below).
  • Printers and Scanners: In the old days, printers were attached to a connector with many pins located on the back panel (called the parallel port). Today, most printers are attached via a USB port, as are scanners. So let’s talk about USB!

Universal Serial Bus (USB)

USB is newer technology for transferring data to and from digital devices, and many devices can now be attached via a USB port. All new PCs have multiple USB ports. If you are buying a new PC, make sure it comes with an adequate number of USB ports and make sure a few ports are located on the front of the system unit for easy access. Some of the devices that connect via a USB port are printers, scanners, digital cameras, video cameras, mice, keyboards, external disk drives, and flash drives.

A very popular device that connects to a USB port is the flash drive, or memory stick. It is a small device about 2” x ¾” that plugs directly into a USB port and is used to store data. Flash drives are inexpensive and can hold gigabytes of data. There are useful for backing up large files and transporting files between PCs. Because of USB technology, external disk drives are also becoming popular. They are much larger than a flash drive but can hold much more data. They vary in size, capacity, and price, but they all attach via a short cable to a USB port.

How storage is measured

Computers talk in “bits” and eight bits equals one “byte.” And 1,024 bytes equal 1 kilobyte (KB). We seldom talk in bytes or KB these days; we talk in bigger numbers.

  • 1,024 kilobytes (KB) = 1 megabyte (MB)
  • 1,024 megabytes (MB) = 1 gigabyte (GB)
  • 1,024 gigabytes (GB) = 1 Terabyte

Let’s put this information to practical use. Here are the capacities today of the various media we’ve discussed: A diskette holds 1.44MB. A CD holds 700MB. A DVD holds 4.7GB. And you can buy a 2GB flash drive that plugs into a USB port for under $50. The size of the average photo, from personal experience, is about 700KB … so we’ll round that up to 1MB. And in my experience, a 2-page letter is about 25KB. So on a diskette you can store one photo, or 57 letters. Not very useful if you are storing photos! A CD can hold about 700 photos, or 28,000 two-page letters. Not bad! And a DVD holds even more.

You know, in many ways YOU are just like a PC. Your brain is a Central Processing Unit. Your long-term memory (file cabinet) is like the hard disk where data is permanently stored, and your short-term memory (working are) is like the PC's memory. And all of them work together each to control your eyes, ears, fingers, toes and to produce work! I hope you now have a much clearer picture of what a PC is all about. Please see my other articles that will help you use your PC!

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