Chapter 2
 The System Unit, 
Processing, and Memory
Key Topics
 o Binary, Bits & Bytes
 o System Unit
 o Processing Devices
 o Memory
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Binary, Bits & Bytes
 o All types of data must be converted into a form which can 
be processed by a computer.> Dual Core CPUs contain two cores
Quad Core CPUs contain four cores
Octa Core CPUs contain eight cores
CPUs for servers can contain up to 64 cores 
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Processing Devices
 Components of a CPU Core
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Processing Devices
 o Processing performance of a computer mainlydepends on:
CPU's Clock Speed - measured in Hz (typically in GHz)
CPU's Word Size - amount of data which can be handled at 
once - measured it bits (typically 32 bits or 64 bits)
Bus Width - number of wires/paths in a bus - measured in bits 
(typically 8, 16, 32 or 64 bits)
Memory Size- RAM and Cache - measured in Bytes (typically in 
GBs)
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Processing Devices
 o Since processing related to graphics (images and videos) is 
very intensive, most computers have a separate processing 
device for graphics known as Graphics Processing Unit (GPU).Common prefixes are:
Kilo - Thousand (1,000)
Mega -Million (1,000,000)
Giga -Billion (1,000,000,000)
Tera- Trillion (1,000,000,000,000)
Peta -Quadrillion (1,000,000,000,000,000)
Exa-Quintillion (1,000,000,000,000,000,000)
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Encoding Data into Binary
 1) Text data is encoded into 
binary using coding systems 
like ASCII and Unicode.Examples of compression include:
For graphics, BMP files can be compressed into JPG
For audio, WAV files can be compressed into MP3
For video, AVI files can be compressed into MP4
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System Unit.2) Graphics data (images and 
drawings) is encoded into binary 
by converting colour value of 
each pixel into binary. 4
Encoding Data into Binary
 3) Audio data is encoded into binary by first converting 
sound waves into numerical form and then converting 
the numbers into binary.19
Memory
 o In addition to RAM, other common types of memory include: 
> Registers- volatile - fastest type of memory built into the CPU 
needed for storing data during processing.o Compression mostly involves removing unnecessary bits 
from the file while keeping quality at an acceptable level.> External hardware connects using Portsor wireless technologies.o Ports are used by devices which use wires to connect to the 
motherboard, Examples:
HDMI port is used to connect a monitor.o CPU consists of circuitry and components packaged together and 
connected directly to the motherboard.They contain 
processing components (cores) of multiple independent 
processors on a single chip.17
Processing Devices
 o Processing devices and other circuits can generate a lot of heat and 
require suitable cooling arrangements.Prefixes:
 o Prefixes are often used to express larger quantities of bits 
and bytes.o System Unit houses the processing hardware for a computer and also 
contains other components such as storage devices.> Internal hardware is connected through electronic paths called Buseswhich 
are built into the motherboard.> USB ports connect USB devices.Questions ???21