Difference Between Memory Types
,Importance Of A Hardware Compatibility List
Hot swapping/ hot spare: A hot spare
is a spare unit that is ready to take on the job of the
main unit in the even of failure. Hot spare refers to the
physical unit such as a disk drive or even a standby computer,
such as in a clustered configuration. The failure may or
may not be noticed by clients. For example, if the RAID
system is configured with RAID 0, a failure may be noticed
by the clients, whereas, if configured with RAID 5, the
failure may not be noticed (in case of single point failure).
Hot-Swapping is the ability to add and remove devices to
a computer while the computer is running and have the operating
system automatically recognize the change. Hot plugging
is also called hot swapping
Memory Types RAM stands for Random Access
Memory. There are basically two types of RAM:
1. DRAM - Dynamic RAM, and
2. SRAM - Static RAM. SRAM, being very expensive, commonly
used for Cache memory. DRAM, being cheaper, is used for
DDR (Double Data Rate)
DDR SDRAM/ DDR/ DDR1: It transfers data on both rising
and falling edges of the clock signal. It operates at
2.5 volts. DRR RAM runs at twice the processor speed.
It uses prefetch buffer which is a memory cache on RAM
module that stors sata before it is actuly needed. This
buffer size is 2 bits. Connector size is 184 pins.
DDR2: It is an enhancement of DDR SDRAM with prefetch
buffer of size 4 bits. It also has enhanced registers
and on-die termination. It also works at higher bus
speed. It operates at 1.8 volts. Pin size is 240 pins.
DDR3: It is an enhancement of DDR2 with prefetch
buffer size 8 bits. Data rate is twice that of DDR2.
It operates at 1.5 volts. Pin size is 240 pins.
Fully Buffered DIMM
It is a memory technology which can be used to increase
reliability and density of memory systems. Conventionally,
data lines from the memory controller have to be connected
to data lines in every DRAM module, i.e. via multidrop
buses. As memory width, as well as access speed, increases,
the signal degrades at the interface of the bus and