DATA COMMUNICATION&

NETWORKING

Prepared By :

MUHAMMAD NAUMAN

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

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

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).

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

The Numbers representing that Written On The Processors:

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.

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).

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

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.

Where ROM Exist Physically On the Computer:

The ROM is pointed with Red Square box on the board.

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.

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

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

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

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.

• 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.

How Data Travelled b/w the CPU,Cache Memory & RAM

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

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.

Questions