Hardware Basics

The basic parts of a computer, and the terminology people assume you know.

Home computers almost all have a few things in common. They have a mouse and a keyboard and a monitor and a box that holds the guts. Some Macintosh's and laptops hide the guts in the monitor or keyboard but the guts are somewhere.

Mice

Most home computers have a mouse. (Yes, the plural is mice.) Most PCs have a two or three button mouse. The mouse will typically have a left and a right mouse button. Some have an additional center button or a scroll wheel that can be used as a button or to scroll through content that the user might be looking at. Don't spend too much on a mouse unless you are really a graphics designer or working with something else that requires a significant amount of careful mouse work. Most people can get by just as well with the mouse that comes with the computer. If you have the option, choose an 'optical' mouse as it will work longer and more reliably without cleaning than a roller ball based mouse. If you have a roller ball based mouse, every once in a while (say once a month) you should open up the little piece on the bottom that holds the ball in. Then drag your finger across the rollers until the lint that it gathers has broken loose. Use a pair of tweezers to pick the lint out and then blow out the mouse to get any dropped pieces and reassemble.

Monitors

The monitor is the large TV looking screen. There are flat ones and large bulky ones and many different sizes. Typically modern monitors have the ability to display color and pictures. The monitor is connected to a graphics card which is what the computer uses to communicate with it. Most people are fine with the graphics card they get with their computer, but upgrades are not usually terribly expensive. Spending more than $150 on a graphics card is a waste unless you have special needs (as heavy game players occasionally do.) There are really two classes of Monitors, LCD and CRT. CRT are the ones that resemble a squarish box, and LCDs are the flat ones. If you have an LCD, do NOT push on it to make the funky colors.

CPU

This holds in the guts

The Central Processing Unit is a somewhat generic term sometimes used to refer to the processor and other times used to refer to the box that houses the motherboard. You can identify the CPU by tracing your monitor or mouse or keyboard wires. They will plug into the outside of the CPU. Laptops and wireless keyboards and wireless mice sometimes make this slightly more difficult, but monitors are almost never actually wireless. Sometimes the monitor will be directly connected to the CPU but other times (and most commonly) there will be a wire that goes from the monitor to the CPU. The monitor will sometimes have a power cord as well, but that is usually easy to distinguish. If your monitor only has one wire and it connects to a box, then that box is certainly your CPU.

If your monitor has a power cord and the other wires connect only to things that communicate with the computer like keyboards, mice and printers then you may have a Macintosh (or very rare system) that has combined the CPU with the monitor.

Processor

The processor is the brain of the computer. A few systems have more than one but typically home computers have only two at most. These are the part of the computer where the strangest magic happens. Few people can explain exactly how the processor does exactly what it does, but a generic explanation is somewhat simpler. The processor is responsible for making all the decisions and handling all the calculations that allow a computer to respond to input. It will take instructions in binary and respond with different instructions or information that control practically everything else the computer does.

Processors are extremely complicated pieces of machinery and are typically the most expensive part of the computer. They cannot do anything without instructions. They will be plugged into the motherboard and they will communicate with the RAM to change what the computer is doing or send the instructions to the other parts of the machine.

Do:

1. Feel okay about paying a little extra for a better processor, it is probably worth it
2. Pay attention to what processor comes with a computer and how that compares to the programs you want to run

Don't:

1. Get the most expensive processors, the price always comes down a lot after a couple months and there are sometimes bugs in the newest processors
2. Assume that two is better than one, or that 64bit is the same as two 32bit processors. Think of them as engines and the bits as cylinders. The numbers do matter.
3. Get caught up in the Gigahertz hype. Sometimes a processor with less Gigahertz (GHz) performs better than one with more. It is logical to assume that the measurement is a reasonable starting point for comparisons, as the speed of a processor is often measured in GHz, so more is better, but a 2.8GHz processor is not worth a thousand dollars more than a 2.5GHz processor.

Motherboard

The motherboard enables communication between all the other parts of the central parts of the machine. The motherboard has what amount basically to wires that enable information to pass between cards and RAM and the CPU. It will also have slots and sometimes adapters that allow other things to be plugged into the main system. Cards are often plugged into the motherboard to enable things like Ethernet connections, printers or monitors to communicate with other parts of the system. Sometimes these things are built directly into the motherboard but other times they will have a card that plugs in and then other things plug into the cards.

One of my computes has an ethernet adapter card plugged into a motherboard that also has a built in ethernet adapter. (The ethernet adapter in this case allows communication with the Internet connection.) This allows that computer to connect to two network systems at the same time.

Another computer has an on-board video adapter and a second video adapter card. The on-board video adapter doesn't work and the second one allows the monitor to be plugged into something that works.

Most of the motherboard settings can be edited through the BIOS settings. When a personal computer first starts booting up it will usually display some basic black screen with very simplistic information. You can usually hit a key like Delete or F1 to edit the settings. The BIOS has the information that gets the computer from the point of being too simple to talk to the monitor, the hard drives and other essential systems. The job of the BIOS is to send the instructions to the system that get the process of loading an operating system started. Typically the BIOS has some options that allow the user to specify where to look for the operating system. Common options include a CD ROM drive, floppy drive or hard drive. Some computers have multiple instances of any of those. Some computers also are able to use their ethernet connection to find an operating system, but this is not commonly used on home machines.

Cards

Cards expand the functionality of the motherboard. Some cards allow communications with keyboards or mice but more commonly allow use of a phone line or ethernet connection or monitor. Other cards enable communication with scanners, cameras, printers and sometimes special devices like external hard drives.

USB and Firewire

Most modern computers have special connections that are designed to simplify the process of connecting things to your computer. They allow people to connect mice, keyboards, hard drives, CD ROMs, scanners, network systems, printers or any other device that might be dreamed up to a single type of connection.

Internet connection hardware

There are four common pieces of hardware that enable computers to communicate with other computers. Groups of computers connected this way are generally referred to as a network. The biggest network is the Internet and as such it is hardly thought of as just a network. The Internet is a network of networks. Computers connected to the Internet can talk to networks or computers all over the world. The Internet has special characteristics that set it apart from other types of networks but it is not inaccurate to think of it as one large way of networking computers.

• Modems are communication devices that allow a computer to connect to a network, typically the Internet, through a standard phone line. The phone line will plug into the modem which will have a phone type of connection, referred to as a port, usually on the back of the CPU. Modems are sometimes built into the motherboard and other times are on a card plugged into the motherboard. Less commonly there is a connection from an external modem to a different type of connector like a serial port that allows the computer to talk to the modem and thus to the Internet. Modems are specifically a type of hardware that use analog (normal) phone lines but often other devices are referred to as modems since the modem is the most prominent piece of hardware that made networking, particularly connecting to the Internet, possible.
• Ethernet Adapters are communication devices that look a lot like a big phone cord. Ethernet is actually a protocol but is almost always used in conjunction with a cable has a plastic plug that connects your computer to another device that in turn handles the communication with the rest of the network. Sometimes ethernet adapters will plug into Cable Modems, DSL modems, work network outlets or even ISDN modems. It is worth mentioning that these devices are almost never actual modems, but the terminology is common enough to ignore that technicality. If your computer has a wire with what looks like a large phone line plug inserted in it on one end and the other plugged into another device for a network connection, then it is likely an ethernet connection. The card that enables this type of plug in is often called an adapter. Many home users will have an ethernet adapter that plugs into a router or cable modem or DSL modem.
• USB connections allow the same type of communication but generally require a device rather than an outlet that is a part of a bigger network. USB connectors are often used to connect to routers, cable and DSL modems as well.
• Wireless cards allow communication using the same type of signal that allows TVs and Radios to send information, but they differ in working both ways. Rather than just receive they also transmit information. Sometimes they are referred to as wireless adapters and other times as wireless modems. Some wireless cards allow a direct connection to a bigger network and some just connect to a local wireless router.

Drives

Drives are where stuff is stored

Anything that you want to be available the next time your computer is turned on, that doesn't come from a network, has to be stored on a drive. The way data is measured is in bytes and drives are typically measured in Mega and Giga bytes. Each Megabyte is about one million bytes and each Gigabyte is about one billion bytes.

• Hard Drives
  • This is where the stuff you put on your computer is stored, including the programs that you use. Typical hard drives come in sizes from 20 Gigabytes to 500 Gigabytes. Most people will be fine with anything larger than 50 Gigabytes, but can get by with 20. It is possible to get a working system on as little as 5 Gigabytes, but that requires some experience and knowledge. There are also several different types of hard drives you may encounter:
    • IDE - the most common and usually cheapest. It is not generally as fast as the other types, but is sufficient for most people. IDE is the most common type of drive in home computers more than a couple years old.
    • SATA - SATA (both SATA I and SATA II) are faster types of drives that are becoming more and more common in home computers. They are typically marginally more expensive than IDE drives, but they are significantly faster and becoming the most common choice by computer manufacturers
    • SCSI - this used to be the fastest and is one of the oldest types of drives encountered. They are not very common in home computers, and are typically more expensive than IDE or SATA
    • SAS - this is what is replacing SCSI drives and it is faster and also typically more expensive than the alternatives. For high performance machines this is the hard drive technology of choice
    • External - these are drives that connect to your computer without opening the box and exposing the guts. They typically come in USB and Firewire. It is essential that you choose only the type that your computer can plug into if you purchase one of these. They are also almost always slower than the other types of drives, but are also easier to add to a computer than any of the other types
• CD ROMs - These are the most common way to get information for your computer. CDRs are CDs that can hold anything you want to put on them, but can only be created to hold stuff once. CDRWs are CDs that can be reused and changed. Typical CDRs and CDRWs hold about 700 Megabytes of information. Buying a CD Writer (or CD Burner) is an easy way to make sure you can cheaply store significant amounts of data, but not all CD ROM drives can write, some can only read data. It is important to know which type of drive you are purchasing.
• DVD Drives - These are essentially the same as CD ROM drives, but manage up to 4 Gigabytes of data. They also come in read only and read/write versions. As with CDs, there are one time use writable DVDs referred to as DVDRs and multi-use referred to as DVDRWs. Some drives can manage larger size DVDs but are still more expensive than is generally worth the investment for an average user.
• Floppy Drives - These used to be the most common way to store data. Floppy disks are typically about about 4 inch squares of hard plastic and they can store only about 1.5 MB of data. They are not present on many new computers.
• Thumb Drives - also called Flash drives, these are the fastest storage available. They are usually much smaller than other types of drives and usually plug into a USB port. These are a good way to take information from one computer to another, but most people should not try to use them for anything other than carrying around things like documents, pictures, videos and music.

Fans

Most people don't need to worry about the fan in the computer but it is the part of the machine that is likely to make the most noise. The processor is typically responsible for generating the most heat inside the machine and if it doesn't get cooled somehow, it will melt itself or shut itself off. It is essential for almost every computer to have a fan. If your's starts to make excessive noise, or stops working it is imperative that you have it replaced.

Power supply

If the computer doesn't turn on anymore, this is probably the part that is broken. This is what takes the electricity coming in through the plug and distributes it in a usable form to the other parts inside the CPU. It is not something that most people should try to mess with, as mishandling it can actually be dangerous. If your machine suddenly stops turning on however, it is a good candidate for replacement and tremendously cheaper than replacing the computer.