116 lines
5.6 KiB
Plaintext
116 lines
5.6 KiB
Plaintext
HARDWARE:
|
||
|
||
CENTRAL PROCESSOR UNIT (CPU): Heart of the PC - it contains
|
||
the microprocessor. The CPU is a set of miniaturized circuits that
|
||
does all the "thinking". It controls the interpretation
|
||
(arithmetic-logic unit) and execution (control unit) of instructions.
|
||
It is this CPU in conjunction with RAM that comprise the computer's
|
||
"brain". The CPU does the "thinking/calculating" while RAM contains
|
||
the instructions or "memories". It is the CPU that largely determines
|
||
the operating speed of the computer.
|
||
|
||
BIT: Smallest unit of information recognized by the
|
||
computer. BIT is short for Binary Digit. A Binary Digit can
|
||
be either a 0 or a 1. Several bits make up a byte.
|
||
|
||
BYTE: A group of 8 BITS. This grouping of adjacent binary
|
||
digits (bits) is operated on by the computer as a unit.
|
||
Computers use 1 BYTE to represent 1 character such as a
|
||
letter of the alphabet, a number, a punctuation mark, a
|
||
space, etc. A BYTE is also a unit of measure since it
|
||
represents 1 character. For example, when the letter "A" is
|
||
pressed, the keyboard actually sends the following to RAM:
|
||
10000001 - a set of 8 bits. See RAM, FLOPPY DISK.
|
||
|
||
RANDOM ACCESS MEMORY (RAM): A set of miniaturized circuits which
|
||
represents the working memory of the computer. This is where
|
||
application programs (software) can be loaded from the outside and then
|
||
executed. The larger the RAM the better. A typical single-user
|
||
computer system may contain approximately 640,000 bytes of RAM. (This is
|
||
often abbreviated as 640k RAM: 1 k bytes is actually = 1024 bytes)
|
||
|
||
The RAM is emptied when the computer is turned off - thus it is
|
||
often called "volatile" memory. WHAT YOU SEE ON YOUR COMPUTER MONITOR
|
||
IS ACTUALLY IN RAM ONLY - a temporary storage location. To make it
|
||
permanent we "save" it, or "write" it to a floppy disk or hard drive.
|
||
These devices are not volatile storage - they do not require
|
||
electricity.
|
||
|
||
READ ONLY MEMORY (ROM): This is a special section of memory
|
||
that contains instructions which are activated each time the
|
||
computer is turned on. These instructions are set at the
|
||
factory and cannot be changed - thus, they can only be "read"
|
||
not written to. ROM instructions perform equipment checks
|
||
and initialization of the computer prior to each use.
|
||
|
||
DISK DRIVE: The port in which a floppy disk is inserted. Device that "reads"
|
||
data from a magnetic disk and copies it into the computer's memory (RAM) so it
|
||
can be used by the computer, and that "writes" data from the computer's memory
|
||
onto a disk so it can be stored for later use. Each Disk Drive is labeled
|
||
A,B,C,etc because we often must tell the computer which drive has the disk
|
||
with the information or where to send the information. A Disk Drive reads and
|
||
writes on a 5.25 inch or 3.5 inch floppy disk.
|
||
|
||
FLOPPY DISKS: The most commonly used mass storage device. Allows
|
||
entering programs to RAM and saving data from RAM. Will hold data even
|
||
|
||
|
||
|
||
|
||
|
||
after the computer is turned off. Data on these disks is stored in
|
||
concentric rings called tracks. The Disk surface is a thin piece of
|
||
mylar and is coated with a magnetized material similar to audio or
|
||
video tape.
|
||
|
||
The read/write heads can magnetize and demagnetize the coated surface
|
||
repeatedly. Therefore, the Disk can be used, erased, and reused
|
||
indefinitely. An IBM PC disk holds approximately 360k worth of
|
||
information (250 double-spaced pages of text). This is called a
|
||
Double-sided, Double-density Diskette. Newer, smaller 3.5 inch disk
|
||
exist which hold at least twice as much - 720k.
|
||
|
||
FIXED DISK DRIVE: Usually named disk drive C. It is essentially a
|
||
very large floppy disk. This Fixed Disk (commonly called a Hard Drive)
|
||
is secured within the machine and cannot be seen or transported. The
|
||
storage capacity is so large it is measured in megabytes (1M = 1K
|
||
squared = 1,048,576 bytes). Fixed Disks are available from 5M on up.
|
||
The advantage is that it is enough space to meet most users' total
|
||
storage needs, operates much faster than a floppy (5-10x faster), and is less
|
||
likely to fail since it lives within the protected computer.
|
||
|
||
KEYBOARD: Input device that lets you enter data into the
|
||
computer. The layout is similar to the standard QWERTY
|
||
typewriter keyboard, however there are many extra special
|
||
keys that are defined by the software you are running.
|
||
|
||
MONITOR: A television-like device that the computer uses to
|
||
communicate with you. Typically the monitor displays 80
|
||
columns (characters) by 25 rows (lines) of information.
|
||
|
||
PRINTER: Most users get at least one Printer for their
|
||
computer. It produces a "Hard-Copy" output of your data
|
||
rather than just being able to view it on the monitor. Dot-
|
||
Matrix printers are inexpensive and fast and can draw
|
||
graphics. Letter-Quality printers are more expensive and
|
||
slower but create pages better than typewritten (even
|
||
pressure on each keystroke).
|
||
|
||
MODEM: Short for Modulator/Demodulator. A device to send
|
||
and receive computer output over telephone lines.
|
||
|
||
|
||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
|
||
<EFBFBD>KEYBOARD <20> <20><><EFBFBD><EFBFBD><EFBFBD>Ŀ <20>MONITOR<4F>
|
||
<EFBFBD>Mouse <20><><EFBFBD><EFBFBD><EFBFBD> INPUT <20><><EFBFBD><EFBFBD>><3E> CPU <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> OUTPUT <20><>><3E>Printer<65>
|
||
<EFBFBD>Light Pen <20> <20> RAM <20> <20>Plotter<65>
|
||
<EFBFBD>Microphone<EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20>Speaker<65>
|
||
<EFBFBD>Joystick <20> <20> INPUT <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20> and/or
|
||
<20> OUTPUT
|
||
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
|
||
<20> DISK STORAGE, Tape Storage, Modem, Fixed Disk Storage <20>
|
||
<20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
|
||
***** END OF FILE: Press <ESC> to return to Main Menu *****
|