Upgrading & Fixing Laptops DUMmIES

creating pie-wedge sectors. Now get three dimensional. Every laptop hard

drive has at least one two-sided platter, and some drives have more than one

platter. A cylinderis the same track on all of the platters. (Think of a cookie

cutter, separating the multiple platters into stacked rings.)

That’s as far as I want to get on the technical side of the data structure in this

book, because that’s all the computer needs to know. The disk operating

system that underlies Windows looks at data recorded across tracks, sectors,

platters, and cylinders as a continuous stream of information as if it were

recorded on a long piece of magnetic tape.

Getting with the Format ..............................................................................

A hard drive has all of the parts when it comes out of the clean room at the

factory, but its internal platter(s) are like a blank piece of paper. The com-

puter has no way to know where to put information or how to retrieve it. It is

a blank map.

The solution is to draw a set of circles, lines, and cylinders and create an

index that shows what is where (along with other information, including

when and how). The process is called formattingand includes three steps.

Low-level formatting ..........................................................................

Low-level formattingis usually done at the factory. This involves addition of

magnetic traffic signs that demark the tracks and divide each platter into sec-

tors with codes noting the beginning and end of each. More sectors are at the

longer, outer tracks and fewer at the shorter, inner ones.

Partitioning..........................................................................................

Partitioningis a task done by your laptop maker or by you if you are replacing

the original hard drive or adding a second new storage device. This process

subdivides the wide-open space of the hard drive into useable areas recogniz-

able by your operating system.

First of all, partitioning creates a master boot record(also called the boot sector

or MBR) that contains the very basic index for the location of instructions and

files that the computer needs to consult when it first comes to life; once the

operating system is loaded it works together with the MBR to manage file

124 Part III: Laying Hands on the Major Parts