Drives, Folders and Files
• When accessing a hard disk, whether it is local to your machine or perhaps located on a network, Windows uses a system of drive letters to serve as logical pointers to the different physical drives you have access to. From each drive letter it is possible to access all of your files stored on that particular physical drive.
• If all of the files were held together in one place on each drive, the system would be very difficult to use because of the sheer number of files involved. To help organise your files it is possible to create folders (also referred to as directories) to help divide and even sub-divide the files stored within the various logical drives available. A system of hierarchical folders within folders which represent your hard disk are often referred to as the folder (directory) tree, in the same way the very top of the file system is known as the root folder (directory).
• Finally, at the very end of this structure are the various files which we use.
Data storage devices
• Hard Disk: Stores your operating system, application programs and data. When you save data, it is normally saved to the hard disk. Diskette (floppy disk): The original IBM PC did not have a hard disk, the operating system, programs and data had to be contained in one or two diskettes. Later a hard disk was added, after which point diskettes were used for supplying programs which could be installed (i.e. copied) to the hard disk, or you could back up small amounts of data to the diskette. Most modern PCs are no longer supplied with a diskette drive, due to the fact that diskettes are unreliable and are easily damaged. They only hold very small amounts of data. CD / DVD: These have largely replaced diskettes as a way of supplying programs. They can hold a lot more data. USB Flash Drives: These are small, stick-like devices that plug into a USB port. They can stores Gigabytes of information and are an easy way to transfer data from one computer to another. There are security considerations attached to use of these devices as it is easy to copy large amounts of data to these devices and then take that information out of the office, for this reason many companies ban the use of these devices. When using a USB flash drive the drive is listed within the Windows Explorer program in exactly the same way that your hard disk is. It will have a drive letter associated with it. Network Drives: Seen by your computer as a normal drive, but in reality the network drive is a folder located on another computer which is connected to the network.
File sizes and disk storage capacities
• Each file stored on a disk is a certain size. Some files such as those that only contain text are very small while others containing applications or high videos can be enormous. The capacity of storage disks is often quoted in Gigabytes.
• The basic storage unit is called a bit. The relationship between storage values is illustrated below: Bit: 1 or 0 level of storage is called a Bit
Byte: Eight bits is called one Byte KB, Kilobyte: A Kilobyte (KB) consists of approximately one thousand Bytes MB, Megabyte: A Megabyte (MB) is approximately one million Bytes GB, Gigabyte: A Gigabyte consists of approximately one thousand Megabytes TB, Terabyte: A terabyte (TB) is approximately one thousand Gigabytes
Online Storage
• With the advent of high speed internet connections it is now possible to store your files online. This allows you to access your files from any computer with an Internet connection. If you wish you can also give permission for other people to access your files, for example you could allow family members to access your digital photo collection.
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