Exploaring of System Hardware: where discussed Types of System Hardware Where ROM Physically Exist

1. DATA COMMUNICATION
&
NETWORKING

2. Prepared By :
MUHAMMAD NAUMAN

3. Outline:
1) System Hardware
2) RAM
3) ROM
4) Cache Memory
5) Data Travelling b/w CPU, RAM & Cache
6) Difference b/w PC RAM & IPhone RAM
7) Comparison Of the Tablet PC ,Personal PC & IPhone
8) Comparison Of Core 2 duo & Dual Core

4. System Hardware:
• Any mechanical or electronic device linked in a
computer system, including the central
processing unit and "peripheral" devices such
as printers and external disk drives.
• Different Types of System hardware are
processor, RAM,ROM, & other Peripheral
Devices, etc

5. Processor:
• The processor in a personal computer or
embedded in small devices is often called a
microprocessor. The term processor has
generally replaced the term central processing
unit (CPU).

6. Clock Speed/Clock Rate of CPU:
• Every computer contains an internal clock that
regulates the rate at which instructions are
executed and synchronizes all the various
computer components. The CPU requires a fixed
number of clock ticks (or clock cycles) to execute
each instruction.
• The faster the clock, the more instructions the
CPU can execute per second
• One megahertz is equal to one million cycles per
second

7. The Numbers representing that
Written On The Processors:

8. Contd.
• Part Number: The part Number explaining the
feature containing the CPU. E.g. CPU’s frequency ,
bus speed, package, socket etc.
• Specification Number: In specification number it
will describe the General Information ,
Architecture/ Micro architecture of the processor.
• FPO Number: FPO Describe that from which part
of family is CPU belong, and it interrelate with
part number & spec. numbers.

9. RAM (Random Access Memory):
• Type of computer memory that can
be accessed randomly
• Any byte of memory can be accessed without
touching the preceding bytes.
Types:
• DRAM (Dynamic Random Access Memory)
• SRAM (Static Random Access Memory).

10. Types of DDR SDRAM
• DDR SDRAM:DDR SDRAM stands for double data rate synchronous dynamic
random access memory. DDR RAM transfers data twice per clock cycle, hence the
name double data rate. DDR clock speeds range between 200 MHz (DDR-200) and
400 MHz (DDR-400). DDR-200 transfers 1600 MB/s, while DDR-400 transfers 3200
MB/s.
• DDR2 SDRAM:DDR2 SDRAM stands for double data rate 2 synchronous dynamic
random access memory.DDR2 is twice as fast as DDR which means twice as much
data is carried to the module for each clock cycle. Also due to the design
improvements DDR2 consumes less power as compared to the DDR memory.
DDR2 speeds range between 400 MHz (DDR2-400) and 800 MHz (DDR2-800).
DDR2-400 transfers 3200 MB/s. DDR2-800 transfers 6400 MB/s.
• DDR3 SDRAM: DDR3 SDRAM stands for, double data rate 3 synchronous dynamic
random access memory. In theory DDR3 is supposed to act twice as fast as DDR2
memories. Thus DDR3 speeds range between 800 MHz (DDR3-800) and 1600 MHz
(DDR3-1600). DDR3-800 transfers 6400 MB/s; DDR3-1600 transfers 12800 MB/s

11. ROM (Read Only Memory)
• Computer memory on which data has been
prerecorded.
• Once data has been written onto a ROM chip,
it cannot be removed and can only be read.
• ROM is referred to as being nonvolatile,
whereas RAM is volatile.

12. Where ROM Exist Physically On the
Computer:
The ROM is pointed with Red Square box on the board.

13. Types Of ROM:
1) PROM: Short for programmable read-only
memory, a memory chip on which data can be written
only once.
• Once a program has been written onto a PROM, it remains
there forever.
2) EPROM: Erasable programmable read-only memory .
• EPROM is a special type of memory that retains its
contents until it is exposed to ultraviolet light.
3) EEPROM: Electrically erasable programmable read-only
memory.
• Erased by exposing it to an electrical charge
• EEPROM is not as fast as RAM.

14. Size of ROM
• This ROM included ONLY the OS, and it is
already built in memory.
• We was able to flash a 20 MB Ext. ROM
• Even larger ROM is possible but doesn't make
any sense to us

15. Cache Memory & Its Types:
• Cache memory is a high speed memory kept in between processor
and RAM to increase the data execution speed. It is kept near to the
processor.
There are different levels of cache.
• L1-cache is the fastest cache and it usually comes within the processor
chip itself.
• The L1 cache typically ranges in size from 8KB to 64KB and uses the
high-speed SRAM (static RAM) instead of the slower and cheaper
DRAM (dynamic RAM) used for main memory.
• The Intel Celeron processor uses two separate 16KB L1 caches, one for
the instructions and one for the data.
• L2 cache comes between L1 and RAM (processor-L1-L2-RAM) and is
bigger than the primary cache (typically 64KB to 4MB).
• L3 cache is not found nowadays as its function is replaced by L2 cache.
L3 caches are found on the motherboard rather than the processor. It
is kept between RAM and L2 cache

16. Technical factors why Cache is
divided into categorizes
• Because if the desired data was not found on the internal cache
then it would have to be searched in the main memory (very slow),
then why not insert another level of cache in the middle of the
inside cache and the main memory. After the 2 levels of cache
started being implemented another idea appear that was to split
the inside cache into two caches one for data and another for
instructions. However this has some problems. It is necessary to
design and implement two caches, and for a unified cache the hit
rate is higher because it automatically balances the load between
instruction and data fetches. Even so the evolution is tending to use
split caches. The benefits of cache hierarchy come at a price. Caches
higher in the hierarchy must field the misses of their descendents. If
the equilibrium hit rate of a leaf cache is 50%, this means that half
of all leaf references get resolved

17. Contd…
• through a second level cache rather than directly from the object's source.
• If the reference hits the higher level cache, so much the better, as long as the
second and third level caches do not become a performance bottleneck.
• If the higher level caches become overloaded, then they could actually
increase access latency, rather than reduce it.
• The evolution of several cache layers started to be a reality, it is good for
performance.
• Despite the cache speed difference between L1 and system memory still
meant every time the CPU needed to access system memory, it had to request
the data, and then wait for it.
• A small L1 cache was nice, but it wasn't enough. A level-2 (L2) cache is usually
fast (25ns or faster) RAM.
• Cache size can range from 8KB to 1 MB. There is no hard and fast rule about
cache size, but the general rule is the faster the CPU relative to system
memory, the larger your L2 cache should be. And then why not have a third
level of cache (L3) with a bigger size then L2.

18. How Data Travelled b/w the CPU,
Cache Memory & RAM
• When a command is given to CPU by user then CPU send the
command to Cache memory to check that the given
command is frequently used or not as cache stored the most
frequent and recent data. If the CPU get the data from the
cache it comes back and execute the information to the user.
• And when a user send command to CPU for a process , same
CPU send command to Cache memory to check that the
given command is frequently used or not, CPU explore
completely the Cache memory for the data , if the CPU did
not get the data from the Cache then It goes to RAM for the
data , when CPU get the data from the RAM , 1st it came to
cache and replaced that file/data with the old one data, that
is not used for some time, Then CPU execute the information
to the user.

19. Comparison of Tablet PC, Personal PC
& Iphone
1- Due to size
2- Due to architecture
3- Due to Electricity consumption
4- Due to life time

20. Comparison of Core 2 duo & Dual
Core:
• Intel Dual Core is the first dual-core CPU from Intel. The
Dual core makes use of two cores on a single die i.e it
has two chips in one package. It solves the problem of
overheating of Intel Pentium D without compromising
on the performance.
• Intel Core 2 Duo processors are the next gen
processors from Intel. It is developed with a new
Architecture called Core. The new architecture of Intel
core2 duo makes it a lot better processor that runs
cool. Most importantly the Intel core2 duo is a super
over clocker.

21. Questions