Basic Computer Hardware

Before you will be able to troubleshoot your Mac like a genius we need to go some basics to make sure you are familiar with the common parts of a computer and the fundamentals of how they work.

At the most basic level, a computer consists of a monitor or screen, a keyboard and mouse, and a "box" that contains the CPU (central processing unit), the drives, memory and ports for connecting peripheral hardware.

The CPU is the most fundamental part of the computer. It handles the major processing of information, moving and manipulating data. In a sense, it is the brain of the computer. The CPU can also offload some of its processing to other part of the computer, like the graphics card. The CPU is located on the main logic board of the computer.

Computers generally contain 3 types of memory. The first kind of memory is for long term storage. Long term storage is most commonly hard drives, but can also be floppy disks, tape drives, re-writable CDs and most recently re-writable DVDs. The data on these various types of media all persist even when the computer is turned off. The second type of memory is random access memory, or more simply RAM. RAM is used to store data temporarily that is used frequently when the computer is on. This includes things like the operating system, any applications which are currently running, and any documents or files that are currently open or in use. Any information which is stored is RAM will be lost when the computer is shut down or rebooted, unless it is first saved to some form of storage memory. The last type of memory commonly found in computers is read-only memory, also called ROM. Any sort of media which can only be read and not written to is ROM. The chips that are programmed to start the computers boots process are ROM, as are the more obvious CD-ROMs. Any information stored in a ROM format will still be there on the media when the computer is turned off.

The last topic we will cover regarding basic computer hardware will be how memory is measured. On the most fundamental level, computers only "know" 2 values, 1s and 0s. This is called a binary number system, also called base 2. To take these values literally, the 1 refers to "on" and the 0 refers to "off". Each one of zero is known as a "bit". When the computer organizes the bits into strings of 8 1s or 0s, that is called a "byte". Bytes are the basic denomination of storage on both persistent and temporary memory. When we start to talk about larger capacities of storage you may hear about kilobytes, megabytes and gigabytes. Below I have listed the conversions between the different capacities.

1 bit = one 0 or 1
8 bits = 1 byte
1024 bytes = 1 kilobyte
1024 kilobytes = 1 megabyte
1024 megabytes = 1 gigabyte