Glossary
of
Terms

What's Inside
ESD
integrated circuits
motherboard
CPU
math coprocessor
cache
clock speed
system bus
external bus
CPU revisited
memory
hard drives
disassembly
reassembly

Hard Drives

Hard Drives (HD, HDD)
In the early days of personal computing, files and programs were quite small by today's standards. They required little storage space. Programs and files easily fit on floppy disks. Even the OS (operating system) could be kept on a floppy to be inserted and loaded into memory at start-up.

As the need for storage increased, tape drives were used. These were very slow and storage was linear. This meant that you had to 'fast forward' and 'rewind' the tape continuously. Technology progressed fairly rapidly and program and file sizes increased dramatically. Hard drives were introduced in the early 80's, and the 5MB of storage space they provided seemed to be more than anyone would ever use. Of course, programs continued to become larger, more complex and diverse. People now use computers for a wide variety of applications. Today's entry-level computer has a hard drive with more than 13-20 GB of storage.

You'll often hear that the CPU and the motherboard are the brain and the backbone of your computer, absolutely necessary for the proper function and performance of you system. However, a hard drive failure will definitely bring your computer to a screeching halt. You can lose all your programs, information, data, and your operating system. All you'll see is a flashing cursor on your monitor and an error message indicating a hard drive failure. Also, because your hard drive is a mechanical device, it is more prone to failure.

At one time, the BIOS knew how the drive was sectored (by calculating the information in setup) and would access data through a controller card in an expansion slot on the motherboard. Two cables ran from the controller to the drive, one for information on where to position the read/write heads and another to transmit data.

Today's hard drives have the controller and a hard drive BIOS built right on the drive. Not only does this setup control the read/write operations, but it performs many other functions as well. One of which is to translate or interpret positioning of data to the system BIOS. The system BIOS no longer understands the physical organization of the platters inside

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