3. Memory devices:
A memory is just like a human brain. It is used to store
data and instruction. Computer memory is the storage
space in computer where data is to be processed and
instructions required for processing are stored
The memory is divided into large number of small parts.
Each part is called a cell. Each location or cell has a
unique address which varies from zero to memory size
minus one.
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5. Static RAM
(SRAM)
Its is faster and more
reliable than DRAM. Its
chips utilize less power
the SRAM Chips is
more expensive then
DRAM chips
Dynamic RAM
(DRAM)
DRAM is used for most
system memory
because it is cheap and
small. All DRAMs are
made up of memory
cells.
RAM
RAM stands for Random Access Memory . RAM is also called main memory .
its consists of memory chips on the mother board. It is read/write memory. Data
and instructions are store in it temporarily
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6. PROM (Programmable Read Only Memory).
PROM is blank chip which a programmer can write program or data using
special device. If any error in data in PROM than we can not erase the data.
EPROM (Erasable Programmable Read Only Memory).
The data written in EPROM chip can be erased by using special device and
ultra –violate rays .
EEPROM (Electrically Erasable Programmable Read Only Memory)’
This kind ROM can be written or changed with the help of electrical devices. So
data in this type of ROM chip can be easily modified data
ROM stands for Read Only Memory. The memory from which we
can only read but cannot write on it. This type of memory is non-
volatile. The information is stored permanently in such memories
during manufacture
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7. A storage device may hold information, process information, or both. A device that only holds
information is a recording medium. Devices that process information (data storage equipment) may
either access a separate portable (removable) recording medium or a permanent component to store
or retrieve data.
STORAGE DEVICES
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9. FLOPPY
DISK:
Floppy means soft. Its also
called floppies and diskette.
Its made by flexible plastic.
Its enclosed in cardboard
jacket. And now use for
transfer small data from one
computer to another.
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10. 10
HARD
DISK:
1. Hard disks are sealed in a
chamber
2. Hard disk consists of a rigid
metal platter (usually aluminum)
rather than flexible Mylar.
3.Hard disk spin between 3600 rpm
and 7200 rpm compared to a
diskette 300 rpm.
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MAGENETIC TAPE:
A diskette contains a single flat piece of plastic (the
disk) coated with iron Oxide enclosed in vinyl or
plastic cover. Its also cheaper. Its used for store files
and documents. And also use for transfer information
from one computer to another.
