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- ⌠
- Running MS DOS, by Van Wolverton, pages 26-27
- ⌡
- When you test drive a car, you already know how to start it. The
- test drive is to help you become familiar with the controls, the
- steering, the brakes, the overall "feel" of the car. Now it's
- time to take a test drive with DOS. Your learned how to start
- DOS in the last chapter. It's time to begin learning how to
- control DOS, how to "steer" it in the direction of one task of
- another, and how to call a halt when you want or need to.
-
- That's what this chapter is all about. It introduces you to the
- directory of files that DOS keeps on each disk, and shows you how
- to use the specific keys on your keyboard. You use these keys
- to tell DOS to cancel lines or commands, freeze the display, and
- restart DOS.
-
- To try the examples given here, start up your computer, as you
- did in the last chapter. Enter the appropriate date and time, so
- that DOS responds with the system prompt, A> (C> of you are using
- a fixed disk). Don't worry about leaving your computer on while
- you read the text between examples; DOS is patient.
-
- Note: Part of this chapter deals with keys that have special
- meaning for DOS. If you are not using an IBM personal computer,
- you may want to check your documentation for equivalent keys on
- your system.
-
- Recall from Chapter 1 that information stored on a disk is stored
- as a file. DOS automatically keeps and updates a list of every
- file you save on every diskette you use. This list is called
- directory. If you create and save a new file, DOS adds it to the
- list. If you revise and old file, DOS keeps track of that, too.
- The directory eliminates the need to keep a separate record of
- everything you save on each diskette. You can tell DOS you want
- to see the directory whenever DOS is displaying the system
- prompt.
-
- The example on the next section serves the double purpose of
- showing you a directory and showing you around the DOS system
- disk itself. As you use the system more, you will come to
- recognize many of the DOS commands. Before you look at a
- directory, though, you should know a little about how DOS saves
- your files.
-
- Whenever you create a file, you give it a name, called the file
- name, of up to eight characters. Of you wish, you can add a
- suffix, called the extension, of up to three more letters.
- (Chapter 4 and 5 present more on files).
- Whenever you ask DOS to show you the directory of a diskette, it
- lists your files by name (and extension, if there is one). It
- also shows you the size of your file, in units called bytes, and
- it gives you the date and the time file was either created or
- last changed (that's why DOS prompts you for the date and time).
-
- Note: A byte is the amount of storage required to hold one
- character in computer memory or on a disk. Here are a few
- familiar items and their sizes, in bytes: the letters abcd, 4
- bytes (1 byte per letter); the words United States, 13 bytes
- (blanks count); a double-spaced, typewritten page, 1500 bytes;
- this book, 600,000 bytes (approximately).
-
- Depending on which version of DOS you're using, and whether your
- drives use one or both sides of a diskette, your diskettes hold
- from 163,840 to 368,640 bytes. For convenience, quantities the
- large are usually given in kilobytes, or K. One kilobyte equals
- 1024 bytes, so the capacity of your diskettes can range from 160K
- 360K.