Copy Link
Add to Bookmark
Report
If You Have Never Used Computers Before Part 6
Hard Disk Management - Level 1:
DOS Disk Operating System (Director Of Services)
---
Master control program for the flow of information within a PC. One of
its primary functions is to oversee all disk activities -
reading/writing information from/to a disk, and loading/executing
programs. It controls (links) all hardware devices so they may
communicate with one another including:
Floppy Drives: 5.25", 3.5"
Hard Drives: 10mb, 20mb, .....
Ram Disk: Simulates a disk drive from within RAM
Laser Disk: "CD's" for computers
Tape Storage Device: Backup system typically using cassette type
tapes
PLUS, Screen, Keyboard, Printer, Modem, Mouse, ...
As if this wasn't enough, this modest software called DOS also keeps
track of the current time and date, and the usage of all memory
locations within RAM.
Once DOS has been properly BOOTed, you will see the familiar "DOS
Prompt":
A>
This says: 1. DOS has been properly installed
2. "A" is the default drive
3. DOS is awaiting your next command
HARD DISK DRIVES
----------------
Also called Hard Drive, Hard Cards, Fixed Disk Drives. Hard Drives are
essentially large floppies housed within the computer. They are much faster,
much higher capacity, and less likely to fail due to the safe environment from
within which they operate.
Hard Disk cost is related to its capacity and it Access Time. Access Time is
the amount of time it take the disk to locate a random piece of information.
Access Time is measured in milliseconds (ms-millionths of a second). A fast
one would be 28ms, a slow one 65ms.
DOS REALITIES
-------------
There are three types of FILES that may be successfully "executed" from
the DOS Prompt:
1. *.EXE Commands ("EXECUTE" Program files Lotus, dBASE,....)
2. *.COM Commands ("COMMAND" Program files Lotus, dBASE,....)
3. *.BAT ("BATCH" Custom programs )
To successfully execute one of the *.EXE, *.COM, or *.BAT command
files, the file itself must be either:
1. In the Current directory
2. Within a directory that is part of the DOS "PATH" command
Batch (.BAT) files are the only executable files you can write using a
simple word processor, or DOS's built in Line Editor (EDLIN) - more later.
BOOTING (or Bootstrap) To load and execute the Disk Operating System-DOS
-------
This term comes from the phrase "pull yourself up by your own bootstraps".
This happens within a PC when it is turned on. Actually, a built-in program
(ROM) is executed, then a couple of "hidden" files from the ROOT directory
(hard drive) or DOS Disk (floppy disk), then COMMAND.COM (DOS internal command
interpreter) followed by the Optional CONFIG.SYS and AUTOEXEC.BAT files.
COMMAND.COM: Must by loaded for DOS to operate properly, it contains
the Internal DOS commands - those used most often: Copy,
Dir, Del, etc. The remainder of files on the DOS disk
are called External Files (DISKCOPY, CHKDSK,...). To
utilized one of these commands, the DOS disk must be
accessible.
CONFIG.SYS: Optional. If it is located on the Disk that you are
BOOTing from, DOS will "open" it and read and interpret a
list of system configuration commands. This is a ASCII
text file which can be created by any text editor.
Configuration commands include: FILES, BUFFERS,
DEVICE,...
AUTOEXEC.BAT: Optional. An ASCII text file. "Opened" and read after
CONFIG.SYS, IF it exists on the BOOT disk. A "batch"
file. A set of DOS commands and other special commands.
SOME FREQUENTLY USED DOS COMMANDS WITHIN A HARD DISK ENVIRONMENT
----------------------------------------------------------------
A Hard Disk is just like a floppy. However, due to its size additional file
management commands are needed. The following can also be used on floppy
disks, but they are most common in Hard Drive Environments.
INTERNAL ³ EXTERNAL (Insert DOS in Drive A)
³
MD ³ CHKDSK
CD ³ BACKUP
RD ³ RESTORE
PROMPT ³ SUBST
PATH ³ TREE
**-- Internal DOS Commands -
MD - Make a directory (see below)
CD - Change to a directory (see below)
RD - Remove a directory - must be rid of files first (see below)
PROMPT $p$g - Changes the way the DOS prompt is display. $p$g insures that
the current directory is shown at the prompt. Very useful.
Usually "set" in the AUTOEXEC.bat file (see below)
PATH=c:\DOS;c:\BATCH;c:\UTILITY
Sets up a command (*.EXE, *.COM, *.BAT) search path in the DOS
environment. When a command is issued from the DOS prompt, it
first looks in the directory you are currently in, then looks in
each directory noted on this path. Usually this command is built
into the AUTOEXEC.bat file (see below)
**-- External DOS Commands -
CHKDSK C:\*.* /F
Checks the integrity of disk files - the level of fragmentation of files.
Indicates the number of files and amount of free storage space remaining on
the disk in drive A. It also indicates the amount of RAM storage.
If any lost clusters are found (data without a home), they can be converted
to *.CHK files so you can delete them to free up the disk space.
SUBST E: c:\LOTUS\123FILES - Assigns a 1-letter drive ID to a
directory path
SUBST E: /D - Cancel previous designation
TREE /F - Displays a list of files and directories on the disk.
/F - more detail - all files, all directories
BACKUP (see below)
RESTORE (see below)
DIRECTORIES
-----------
As previous mentioned, a hard disk is essentially a large floppy disk.
However, it offers some distinct advantages:
Is much larger
Stays inside the machine
Operates (transfers data) at a much higher rate (5-10x)
Because a Hard Disk is so much larger than a floppy, we use an
additional file organization tool called SUBDIRECTORIES.
If a floppy is like a filing drawer, than a Hard Drive is like a wall
of file drawers, each drawer call a SUBDIRECTORY.
DOS lets you organize files using tree-structured directories rather than a
single directory. In other words, since a 20 meg (20,000,000 byte) capacity
hard drive can contain approximately 60 floppy disks worth of files, an
additional organization tool is needed. The creation of SUBDIRECTORIES allows
us to subdivide a disk to contain related files. It's as if we have many file
cabinets available to store our files rather than a single giant one.
DOS permits up to 112 files on a floppy disk. However, with that many
it is a labor to examine via a DIR and it also slows DOS's file access
and retrieval.
ROOT DIRECTORY - Main directory - it provides support for all the
SUBDIRECTORIES. It contains all the SUBDIRECTORIES.
Each SUBDIRECTORY can contain files as well as other SUBDIRECTORIES.
These other Subdirectories could be thought of as SUB-SUBDIRECTORIES.
To use a file in a different drive we have specified the drive and
filename (B:Filename.ext). Similarly, if we want to access a file in a
SUBDIRECTORY we specify a PATH, OR make that SUBDIRECTORY the "current"
one.
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ROOT DIRECTORY³
³ ³
³ files³
ÀÄÄÄÄÄÄÂÄÄÄÄÄÄÄÙ
³
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ ³ ³
ÚÄÄÄÄÄÄÁÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÁÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÁÄÄÄÄÄÄÄ¿
³SUBDIRECTORY ³ ³SUBDIRECTORY ³ ³SUBDIRECTORY ³
³ files³ ³ files³ ³ files³
ÀÄÄÄÄÄÄÄÄÂÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÂÄÄÄÄÄÄÄÙ
³ ³
ÚÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³
ÚÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄ¿
³"SUB-SUBDIRECTORY"³ ³"SUB-SUBDIRECTORY"³ ³"SUB-SUBDIRECTORY"³
³ files³ ³ files³ ³ files³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
PATH: A PATH specifies the names of the directories that DOS must go
through from the ROOT DIRECTORY to get to the file. The directories
are separated by a forward slash ( \ ). (NOT the same as the DOS PATH
command noted above)
EX: C:\123FILES\PROJECTX\BUDGET.WK1
C:\ Root Directory
³
ÃÄ 123FILES Lotus files Subdirectory
³
ÀÄÄÂÄÄ PROJECTX Sub-Subdirectory containing all "PROJECTX"
³ files
³
ÀÄÄÄÄÄ BUDGET.WK1 A specific Lotus file called BUDGET within
the PROJECTX Subdirectory
DOS & SUBDIRECTORIES - there are only 3 key commands in dealing with
Subdirectories: MD, CD, and RD
TO MAKE A SUBDIRECTORY
----------------------
MD dirspec - Internal - to MaKe a DIRectory -dirspec is the name of
the subdirectory or its PATH
EX: C>MD 123FILES <ENTER> - This creates a subdirectory
called 123FILES
- Naming a SUBDIRECTORY follows the same rules for
file naming, except extensions are not used
- You can created unlimited number of SUBDIRECTORIES
- Identical Filenames can exist in different SUBs
(Remember, 2 files with identical filenames CANNOT coexist
in the same SUBDIRECTORY)
TO CHANGE THE "CURRENT" SUBDIRECTORY
------------------------------------
The computer can only have 1 "file drawer" open at a time - thus this is
called the current directory. Unless instructed otherwise, the computer will
assume all files sought and sent will go into this current subdirectory.
CD\dirspec - to Change the "current" Directory
- EX: C>CD\LOTUS <ENTER> - This makes a subdirectory
called LOTUS the current one
TO REMOVE/ERASE A SUBDIRECTORY
------------------------------
1. First make this directory the current one C>cd/dirspec
2. DELETE all the files within this directory
C>DEL *.*
It will ask if you are sure - Y
3. Go to the ROOT DIRECTORY C>cd\
4. RD dirspec - Reove Directory
C>RD dirspec
***** END OF FILE: Press <ESC> to return to Main Menu *****
