Computer memory

The computer is data storing device.There are many catagories of memory namely:primary,secondary,ROM ,RAM,registers,accumulators,floppy,disk,CD-ROM e.t.c.
The processing capacity of computers does not only depends on a capacity or primary memory.A mwmory system can be centralised or distributed.

Centralised
All processors that exists in a system can be shared as one common memory unit which is also preffered as highlycoupled system.
Features:
# In expensive
# Easy to control
# High use of avialable space
Distributed
In this system such processor has a private or local memory as well as common memory.It is also reffered as locely occupied system.
Features:
# Several memory unit can be kept busy at the same time.
# Since each proccesor has its own private memory they can be simultaneously engaged to perform local processing.
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computer memory
Thursday, March 25, 2010

Memory Hierchy
The memory unit is an essential component in any digital computer since it is needed for storing programme & data.The memory unit that communicate directly with cpu is called main memory.
#note:Devices that provide back-up is called auxillary.
The total memory of computer can be the memory in hierchy of components.The memory in hierchy system consists of all storage devices employed in a computer system from the slow flow high capacity auxillary memory through a relatively faster main memory.
A veryhigh speed memory is called cache memory.It is used to increase the speed of processing by making current programs & data one available to cpu at a rapid rate.
The cache memory is employed in computer system to compensate.for speed of differential between main memory acess time & processor logic.
CPU logic is usally faster than main memory acess time with the result that processing speed is limited primarily by the speed of main memory.
A technique used to compensate for mismating in operating speed is to e,ploy an extreamly fast by cache.The cache is used for storing segments of programmes currently being executed in CPU & temporary data frequently needed in the present calculation.
Cache memory
Simply a luffer memory present between processor (CPU) & main memory is called cache memory.It's capacity is measured in unit ratio.
It's charactersticts are:
# Very small in sieze but expensive.
# It is 5-10 times faster than main memory.
# It increases storing capacity of main memory & increase speed of processor.