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• PRESENTED BY
•MUHAMMAD JUNAID ABBASI
SYSTEM CLOCK• It is an ELECTRONIC component &
generates ELECTRIC signals at a fast speed.
• It controls all functions of computer using clock ticks, These ticks are known as CLOCK CYCLE.
• The speed at which CPU executes instructions is called CLOCK SPEED.
• Processor speed is measured in MHz and GHz.
SYSTEM CLOCK
MIPS• MIPS stands for Millions Of
Instructions Per Second.• Speed of workstations and some
server computer is measured in MIPS.• Computer can operate up to several
thousand MIPS.• Workstations can perform 100 or
more and mainframes can perform 200-1,200 MIPS.
FLOPS• FLOP stands for Floating Point
Operations Per Second.
MEMORY• Data and Instructions are stored in
memory to be executed. They are stored in memory as bytes
during execution.• Each byte in the memory has its unique
address that identify its location.• It is also called Primary storage.
MEMORYMemory Stores the following three
items:1. Operating system and other
system software.2. Application programs3. Data
MEMORYThere are two types of Memory.• VOLATILE Memory: Loses its contents when computer is
turned off.• NON VOLATILE Memory: Doesn't loses its contents when
computer is turned off.
Random Access Memory
• Random access means that each individual byte in the entire memory is directly accessible.
• RAM is used to store an ever changing parade of programs and data.
• A program must be loaded into the RAM before execution.
• It is also called VOLATILE memory.
TYPES OF RAMMemory comes in variety of forms.
There are two main types of RAM.• Static RAM• Dynamic RAM
Static RAM• The memory cells are made of digital
gates.• Each cell can store its value without any
need to refresh the data as long as the power is available.
• CPU doesn't wait to access data.• It’s normally used to build a very fast
memory known as CACHE memory.
Dynamic RAM• It is the type of memory that is used in
most computers.• DRAM requires an electric current to
maintain its electrical state.• The electric charge of DRAM decrease
with time that may result in loss of data.• The processor cannot access the data of
DRAM when it is being refreshed.
Difference b/w SRAM n DRAM
SRAM DRAM
• It is faster then DRAM.
•It is slower than SRAM.
• It is more expensive.
•It is less expensive.
•It does not need to be power-refreshed.
•It has to be refreshed after each read operation.
•It utilizes less power. •It utilizes more power.
Memory Module• RAM is mounted on a small circuit
board called MEMORY MODULE.• This memory is mounted on the
mother board.
There are three types of memory module.
• SIMM• DIMM• RIMM
Types of memory module
• SIMM Stands for Single Inline Memory Module.
• In this Module pins on the opposite sides of the circuit board are connected together to form a single set of contacts.
SIMM
DIMM• DIMM stands for Double Inline
Memory Module.• In this module the pins on opposite
sides of the circuit do not connect and form two set of contacts.
RIMM• RIMM stands for Rambus Inline
Memory Module.• It houses SDRAM chips.
Read Only Memory• Rom stores data instructions
permanently.• These stored instructions cannot be
changed or deleted.• When the power is switched off the
instructions stored in it are not lost, that’s why it is also called NON-VOLATILE memory.
• It contains small set of instructions called ROM BIOS.
Types of ROMDifferent types of ROM are as
follows:• PROM• EPROM• EEPROM
PROM
• PROM stands for programmable Read Only Memory.
• This form of ROM is initially blank, user can write data on it using special devices.
• If there is any error in writing the instructions, the error can not be removed from the PROM.
EPROM• It stands for Erasable
Programmable Read Only Memory.• User can erase data stored in
EPROM chips by exposing the chip to ultra violet light.
EEPROM• It stands for Electrically Erasable
Programmable Read only Memory.• In this memory user can read &
write instructions using ELECTRICAL PULSES.
• If there is any error, the user can erase the contents ELECTRICALLY.
Difference b/w RAM n ROM
RAM ROM•It is temporary memory
•It is Permanent memory.
•It enables data to be both read & written to memory.
•It enables data to only read to memory.
•Data can be changed or deleted.
•Data can not be changed or deleted.
Difference b/w RAM n ROM
RAM ROM
•Instructions are written at the time of execution.
•Instructions are written at manufacturing time.
•Instructions in Ram are continuously changing.
•It is not possible to write new instructions on RAM.
•It’s volatile memory.
•It’s non-volatile memory.
Difference b/w PROM n EPROM PROM EPROM
•Instructions written on it can not be erased.
•Instructions written on it can be erased.
•If there is an error while writing on PROM, it becomes unusable.
•If there is an error while writing on EPROM, it can still be used again.
•The user can write instructions on PROM only once.
•The user can write instructions on EPROM many times.
REFRENCES• The concepts of Information Technology BY………..IT SERIES• Information Technology “THE BREAKING WAVE” BY………… IRWIN MCGRAW-HILL• WWW.GOOGLE.COM• WWW.ENCYCLOPEDIA.COM
THANK `s
THANK `s
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