Disks and Drives
Er Abhishek Kumar Agrahari
DOS Tutorial
519 Views
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Because most of our computers Memory (RAM) is temporary, its contents are erased when we switch off the power. We need a place to store the Operating System, application programs and our work. That’s where disks come in, we store any information you want to keep onto disks. |
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There are two types of disk: |
1. Floppy disks & |
2. Hard disks. |
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1. Floppy disks (Diskettes) |
A disk is a magnetically coated disk of thin plastic, inside a rigid plastic cover. |
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We can use Floppy disks to: |
• Transfer information from one computer to another. |
• Store the Operating System, or application program and our work, if we don’t have a Hard disk. |
• Keep a copy of information that we have on our Hard disk (Backup). |
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We need only format a disk once. After that, we can use the disk again and again without having to reformat it. Formatting a disk we have previously used erases any data on the disk, so only reformat a disk if we are sure we don’t need any of the data on it. |
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Choosing disks |
Diskettes come in various forms, so it is important to choose diskettes that match the type of diskette drive installed in our computer. |
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Several different types are available: |
• 5.25inch 360 Kbytes – Very rarely used now |
• 5.25inch 1.2 Mbytes – Uncommon but still in use |
• 3.5inch 720 Kbytes – Getting less common, still in use |
• 3.5inch 1.44 Mbytes – The standard in most modern computers. |
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It should be noted that:- |
• A 720 Kbytes drive can only read and write to a 720 Kbytes diskette |
• A 1.44 Mbyte drive can read and write to both 720 Kbytes and 1.44 Mbyte diskettes. However we must use special formatting instructions to format a 720 Kbytes diskette in a 1.44 Mbyte drive. |
• The visible difference between a 720 Kbytes diskette and a 1.44 Mbyte diskette is that there is no extra notch on a 720 Kbytes diskette. |
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2. Hard disks |
A Hard disk is a disk that is enclosed in a permanently sealed metal housing. |
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Hard disks are better than Floppy diskettes in two main respects: |
• We can store much more information on a Hard disk than on a diskette. |
For example, a 40 Mbyte Hard disk holds the equivalent of almost twenty nine 1.44 Mbyte Floppy diskettes. |
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• They are up to 600 times faster at finding and loading information into the computers Memory. |
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