Page 64 - AI Ver 1.0 Class 9
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Projector
A projector is a display device that projects a computer screen onto a flat
surface: like whiteboard or wall. It is most commonly used for home theaters or
in organisations for official presentations.
Projector
Computer Memory
Computer memory holds raw data before it goes for processing and after processing it contains information which
can either be sent to output devices or stored in secondary storage devices for future use. There are two types of
memory in the computer— primary memory and secondary memory.
Primary Memory
This type of memory is necessary for a computer to work. It is also called the Internal Memory. This is the actual
place where the data is stored before it is taken to ALU for processing. Primary memory is of two types: RAM and
ROM.
RAM (Random Access Memory)
It is temporary in nature. The computer holds information in this memory and gets it
when needed. It remembers what you tell them and can even change to remember
new information. It is volatile in nature, which means that data will be erased when
the computer is turned off. That’s why you always save your work! RAM is considered
“random access” because any part of it can be accessed randomly for reading or Random Access Memory
writing of the data.
ROM (Read Only Memory)
It is permanent in nature. It is non-volatile which means even after turning your
computer off, the contents of ROM will remain. The information is coded at the time
of manufacturing the computer. The computer needs this information for its basic
functions.
Read Only Memory
Secondary Memory
Secondary Memory provides extra storage where the data can be stored permanently for later use. It is also known
as external memory as it can be stored anywhere. Examples of secondary memory are compact disc, hard disc,
flash drive, etc.
Hard Disk
A Hard Disk stores and provides quick access to large amounts of data on an
electromagnetically charged surface or set of surfaces. Hard disks are generally fitted
inside the system unit. However, there are external hard disks also available. A hard disk
is made-up of a collection of disks called platters stacked on a cylindrical rod. Each of
which, like phonograph records, has data recorded electromagnetically in concentric
circles or “tracks” on the disk. The capacity of a hard disk varies from a few Gigabytes to
a few hundred Terabytes.
Hard Disk
62 Touchpad Artificial Intelligence-IX

