Memory
Now we discuss about one of the most important parts of computers i.e memory.
Computers generally possess several distinct types of memory, each of which
"holds" or stores information for subsequent use. The vast majority of computer
memory can be placed into one of two categories: primary memory and
secondary memory
Primary memory, often called main memory, constitutes that device, or group of
devices, that holds instructions and data for rapid and direct access by the
computer's central processing unit (CPU). Primary memory is synonymous with
random-access memory (RAM).Modern RAM is made of semiconductor circuitry. RAM is a volatile form of
information storage, meaning that when electrical power is terminated any data
that it contains is lost. There are other semiconductor memory devices accessed
by the CPU that are generally considered as being distinct from primary memory
(i.e., different from RAM). These memory units include cache memory, read-only
memory (ROM), and Programmable Read Only Memory (PROM) and
EPROM (erasable programmable read-only memory
Secondary memory, also called auxiliary memory or mass storage, consists of
devices not directly accessible by the CPU. Hard drives, floppy disks, tapes, and
optical disks are widely used for secondary storage. First, most secondary storage
devices are capable of containing much more information than is feasible for
primary memory (hence the use of the term "mass storage" as
a synonym for secondary memory). A second, and essential, feature
of secondary memory is that it is non-volatile. This means that data is stored with
or without electrical power being supplied to the device, as opposed to RAM,
which can retain its data only so long as electrical power is present.
Like primary memory, many secondary memory devices are capable of storing
information, as well as retrieving it. Magnetic technology devices (such as hard
drives, floppy disks, and tape) have this read-write capability, as do magneto optical drives. However, some mass storage devices can only read data, as in the
case of CD-ROM (Compact Disk-Read Only Memory) drives. CD-ROMs utilize
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optical technology; however, newer optical technologies, such as CD-RW (compact disk-rewriteable), can both read and write information like
magnetic storage devices.
The hard disk is the main, and usually largest, data storage device in a computer.
The operating system, software titles and most other files are stored in the hard
disk.
Now let‘s have a Practice SessionCheck Your Progress 1
1. Find shortcut keys for the following:
a) To Open Help.
b) To repeat the last action performed.
c) To save document
d) To Bold the selected text
e) Change the text in Microsoft Word from uppercase to lowercase or capital
letter at the beginning of every word.
2. List use of following function keys:
F1, F2, F3, F4, F5, F7, F8, F12
3. Type the following passage in MS-WORD
Over the past few years the growth of the computer industry has been quiet
remarkable and today it is the fastest growing industry in our economy.
Nowadays, many schools are equipped with computers for educating their
students. Thereby making computers an integral part of education system.
Teachers and professors use computers for teaching, giving presentations,
assessing various data banks, maintaining database of students,
communication in the form of e mails or chat, browsing the Internet and Preparing students to have a competitive edge in the global job market.
Computers have revolutionized the learning for students in a big way. They
can watch various films on wild life, history, geography, science and
encyclopedias with loud sound and excellent picture quality on
Compact Disc‘ sorDVD‘s.
(a) In this paragraph, there are few spelling errors. Try spelling check for
this. Try to find and replace ‗loud‘ by ‗‗excellent‖.
(b) Now save this paragraph with the name ‗computer‘ on your desktop.
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