Under the Hood

Under the Hood

Did you ever wonder what was inside a PC, laptop, or other microcomputer system? Yes, that's what they originally called them!) What about how they work? A computer is such a miraculous and, may I add precarious invention that we all take for granted nowadays. Exactly how does a bunch of circuitry in a metal box create and process documents, presentations, graphics, spreadsheets, and multi-media, just to name a few functions? Today we will begin to investigate the ins and outs of computers, as well as how to assemble one yourself!

A computer contains basically two types of parts – hardware, the physical equipment that runs your computer, and software, the programs that run on top of the hardware that provide you with all the many wonderful functions you expect. There are many different types of both hardware and software, which interact with each other in several ways.

Hardware Components

First, let's discuss hardware. There are two types of these – internal and external. Before the first PC-IBM computer went on the market in 1981, you could actually purchase your own microcomputer kit in which you connected a primitive floppy drive to a black and white TV and voila – you had a computer! (My brother actually purchased and assembled such a Texas Instruments kit successfully.) However to get back to the topic at hand, nearly any piece of hardware can function either internally or externally. Although today you can buy a computer with almost everything included, it is often possible to supplement an older system with external components or even put together a system yourself. The few exceptions to this rule are certain hardware components, which must be connected to a circuit board (internal) as well as components that are always external, such as a monitor or printer. (Yet if you look at the old Apple/Macintosh systems, you can see that even monitors can be integrated into a single computer unit.)

The table below includes some of the most common hardware types that you will normally encounter. It is in alphabetical order but by no means an exhaustive list.

Hardware name



Broadband Modem


Can be ADSL (asynchronous digital subscriber line), provided through the local phone company or cable, provided by the cable company.

A component, usually rented through the local phone or cable company that supplies a much faster Internet connection than the old Modem cards.

DVD/CD ROM drive/Burner

(Compact disc or Digital Versatile/Video disc)

Internal or external

The original drives only read CDs and were externally connected; then came CD burners, and finally the DVD reader burner.

A device which reads and/or burns (writes a copy) of CDs or DVDs. The type of disc or burner, determines the reading or burning speed as well as the amount of information able to be stored on the disc.

Floppy drive/disk

Internal or external

Not widely used since it holds so little information; a cross between floppy and hard drives is the portable disk drive, such as the Omega drives prevalent about ten years ago.

The floppy drive stores information on small, portable disks, similar to a hard drive. It is backwards compatible device, meaning it exists on present day systems only to enable the reading of older floppy disks, which may still be used.

Hard drive/disk

Internal or external

The type is determined according to its port connection – SATA, IDE, SCSI, or USB.

The ultimate warehouse on your computer, the hard drive stores all information on your system; this includes personal preferences as well as how the computer starts up each time (boot sequence).



Just like the CPU, these are of several types and amounts.

Memory can function solely to start the computer ROM (read only memory), or can exist to run all other advanced computer functions (RAM or random access memory).

Works with the CPU to determine which software to run on the computer and when to run them.

Modem/FAX cards (uncommon)

(abbreviation for modulator/demodulator)

Internal or external

Before the advent of fast Internet connections, these cards connected to your standard phone line to produce a slow, not so reliable connection to the Internet.

Although not commonly used today, they are good to have as a backup when your fast connection is down or to send FAXes directly from the computer to a recipient.


Mostly external, except on some Macs

The older ones use CRT (cathode ray tube) technology, while most recent computers use a LCD (liquid crystal diode)/Plasma screens.

Provides the picture/ interface on your screen.

Motherboard/Logic Board/System Board/Bus


This is the main circuit board on the computer, which holds the drives, CPU, memory, and usually ports. It contains a small battery that supplies power to the CPU and enables the flow of information between all the hardware components, both external and internal.

Network cards

In older laptops, these can still be inserted as an external component. Most all today, however are internal.

Originally inserted as an additional circuit card in the computer, the network card connects to either a local network (LAN), a remote network (WAN) or both. With home computers, network cards often connect to ADSL or cable modems producing a fast, broadband Internet connection.

Portable/backup drives


USB. eSATA, firewire

Provides a direct copy or image of your important files or entire hard drive in case of computer failure.


Internal or external

serial, monitor, parallel, printer, USB

A physical interface between two components of your computer, ports provide for such basic functions as a monitor or printer, or more complicated functions like the downloading of pictures from a digital camera.

Ports can also be virtual, that is software created. We will discuss these in a latter article.



Cheaper ones use bubble jet/ink jet technology, while higher quality printers use laser technology.

Prints your file/document, in either black and white or color, depending on the printer's capabilities.


(central processing unit)


Various types of these exist according to power and clock speed.

Controls all processing operations in the computer at all levels of software functioning.



Unlike all printers, these always use laser technology.

The scanner takes any printed document and scans it into the computer so that it can be saved on the computer's hard drive.

Next time: Whew! Are you still here? If you're not yet overwhelmed, I plan to give an overview on how these hardware components operate and interact with your software to produce the familiar Windows or Mac logo. We will also get into how to buy, configure, and install hardware on your personal system.