System Architectures Outline
▸ Definition of System Architectures
▸ System Architectures Diagram
▸ Types of System Architectures
▸ Benefits of System Architectures
System Architectures Definition
▸ System architecture is the conceptual model that defines the structure, behavior,
and more views of a system.
▸ It’s a representation of a system in which there is a mapping of functionality onto
hardware and software components, a mapping of the software architecture onto the
hardware architecture, and human interaction with these components.
▸ The architectural components and set of relationships between these components
that an architecture describes may consist of hardware, software, documentation,
facilities, manual procedures, or roles played by organizations or people
System Architectures Definition (Cont.)
▸ It describes the physical placement of software components.
▸ System architecture describes how all system components interconnect
and how data links between them.
▸ Architecture can function as a guide or a framework for designing and
developing a new system or can assist in defining a project's goals.
System Architecture Diagram
▸ The system architecture diagram
is a visual representation of the
system architecture.
▸ It shows the connections between
the various components of the
system and indicates what
functions each component
performs.
▸ The general system representation
shows the major functions of the
system and the relationships
between the various system
components.
Types of System Architectures
▸ Hardware Architecture
▸ Software Architecture
▸ Enterprise Architecture
Hardware Architecture
➢ Hardware Architecture refers to the identification of the physical components and their
interrelationships, which allows hardware designers to understand how their components fit into
a system architecture.
➢ It provides software component designers important information needed for software
development and integration.
➢ Parts of a computer hardware architecture:
• Central processing Unit
• Main Memory
• Secondary Memory
• I/O Devices
• Network Connection
Hardware Architecture (Cont.)
➢ Central Processing Unit (CPU): is the part of the computer that is built to be
obsessed with "what is next?”.
• What is next means what instructions should I perform next.
• CPU performs insurrections that already stored in the main memory.
➢ Main Memory: is used to store information that the CPU needs in a hurry.
• The main memory is nearly as fast as the CPU.
• The information stored in the main memory vanishes when the computer is
turned off.
Hardware Architecture (Cont.)
➢ Secondary Memory is also used to store information, but it is much slower
comparing to the main memory. The advantage of the secondary memory is that it
can store information even when the power is off “Permanent”. Ex; flash memory.
➢ I/O Devices are simply our screen, keyboard, mouse, microphone, speaker,
touchpad, etc. They are all the ways we interact with the computer.
➢ Network Connection is used to retrieves information over a network. It is a slower
and at times unreliable form of Secondary Memory.
Hardware Architecture (Cont.)
Software Architecture
➢ Software architecture refers to the logical organization of a distributed system into
software components.
➢ Instead of one big monolithic application, distributed systems are broken down into
multiple components.
➢ The way in which these components are broken down impacts everything from
system performance to reliability to response latency.
Software Architecture (Cont.)
➢ There are many architecture styles which can be applied on software, such as;
• Layered architecture
• Publish-Subscribe architecture
Software Architecture (Cont.)
➢ Layered architecture In a layered architecture, components are organized in
layers. Components on a higher layer make downcalls (send requests to a lower
layer). While lower layer components can make upcalls (send requests up), they
usually only respond to higher layer requests. Google drive is a good example of
layered architecture, where it shows clearly how the three layered are connecting;
1. Interface layer: you request to see the latest doc from your drive.
2. Processing layer: processes your request and asks for the information from
the data layer.
3. Data layer: stores persistent data (aka your file) and provides access to
higher-level layers.
Software Architecture (Cont.)
• The data layer returns the information to
the processing layer which in turn sends it
to the interface where you can view and
edit it.
• While it feels like one cohesive process,
it’s broken down into three (or more)
components on three distinct layers.
• Each layer may or may not be placed on a
different machine (this is a system
architecture consideration).
Software Architecture (Cont.)
▸ Publish-Subscribe architecture or Pub/Sub is a messaging service where the
senders of messages are decoupled from the receivers of messages. There are
several key concepts in a Pub/Sub service:
• Message: the data that moves through the service.
• Topic: a named entity that represents a feed of messages.
• Subscription: a named entity that represents an interest in receiving
messages on a particular topic.
• Publisher (also called a producer): creates messages and sends (publishes)
them to the messaging service on a specified topic.
• Subscriber (also called a consumer): receives messages on a specified
subscription
Software Architecture (Cont.)
▸ Publishers decide what topics their
messages will belong to.
▸ Event bus filters the messages by topic
before delivering them into the relevant
subscribers.
▸ Ex; if publisher sends a massage with
topic A, massage will be forwarded to any
subscribers who have subscribed to topic
A. Similarly, a massage with topic B will
be delivered to sub scribers of Topic B.
▸ News papers, ads, and social networks
are examples of this style.
Enterprise Architecture
➢ Enterprise architecture (EA) is the practice of analyzing, designing, planning, and
implementing enterprise analysis to successfully execute on business strategies.
➢ EA helps organizations to structure IT projects and policies to achieve desired
business results, to stay agile and resilient in the face of rapid change, and to stay
on top of industry trends and disruptions using architecture principles and practices,
a process also known as enterprise architectural planning (EAP).
➢ It is especially useful for large businesses going through digital transformation,
because it focuses on bringing legacy processes and applications together to form a
more seamless environment.
Enterprise Architecture
➢ EA is guided by the organization’s business requirements and that will help lay out
how information, business, and technology flow together. This has become a priority
for businesses that are trying to keep up with new technologies such as the cloud,
IoT, machine learning, and other emerging trends that will prompt digital
transformation.
➢ Zachman Framework provides a structure for organizing information about an
organization’s business, processes, data, applications, and technology. one of the
main framework used for enterprise architecture.
Benefits of System Architectures
• Vision Development and implementation
• Facilitate Faster IT System Changes
• Ensure that the IT plans align with business programs
• Analyze potential cost-saving opportunities
Virtualization Outline
▸ Definition of Virtualization
▸ Definition of Virtual Machine (VM)
▸ Role and types of Hypervisor
▸ Types of virtualization
▸ Benefits of virtualization
Definition of Virtualization
➢ Virtualization is a process that allows for more efficient utilization of
physical computer hardware and is the foundation of cloud computing.
➢ Virtualization uses software to create an abstraction layer over computer
hardware that allows the hardware elements of a single computer—
processors, memory, storage and more—to be divided into multiple virtual
computers, commonly called virtual machines (VMs).
➢ Each VM runs its own operating system (OS) and behaves like an
independent computer
Definition of Virtual Machine (VM)
➢ Virtual machine (VM) is a virtual environment that simulate a physical compute in
software form.
➢ It normally comprise several files containing the VM’s configuration, the storage for
the virtual hard drive, and some snapshots of the VM that preserve its state at a
particular point in time.
➢ A VM cannot interact directly with a physical computer. Instead, it needs a
lightweight software layer called a hypervisor to coordinate between it and the
underlying physical hardware.
Role and types of Hypervisor
➢ A hypervisor is the software layer that coordinates/manage VMs. It serves as an
interface between the VM and the underlying physical hardware, ensuring that each
has access to the physical resources it needs to execute (1). It also ensures that the
VMs don’t interfere with each other by impinging on each other’s memory space or
compute cycles (2).
➢ Hypervisor has two types:
✓ Type 1
✓ Type 2
Role and types of Hypervisor(Cont.)
➢ Type1 interact with the underlying physical resources, replacing the traditional
operating system altogether. They most commonly appear in virtual server
scenarios.
➢ Type2 run as an application on an existing OS. Most commonly used on endpoint
devices to run alternative operating systems, they carry a performance overhead
because they must use the host OS to access and coordinate the underlying
hardware resources.

Types of Virtualization
➢ Desktop Virtualization
➢ Network Virtualization
➢ Storage Virtualization
➢ Application Virtualization
Types of virtualization (Cont.)
➢ Desktop Virtualization allow user to run multiple desktop operating systems, each in its own
VM on the same computer. There are two types of desktop virtualization:
• Virtual desktop infrastructure (VDI) runs multiple desktops in VMs on a central server
and streams them to users who log in on thin client devices. In this way, VDI allows an
organization provide its users access to variety of OSs from any device, without installing
OSs on any device.
• Local desktop virtualization runs a hypervisor on a local computer, enabling the user to
run one or more additional OSs on that computer and switch from one OS to another as
needed without changing anything about the primary OS.
Types of virtualization (Cont.)
➢ Network Virtualization Network virtualization uses software to create a “view” of the network
that an administrator can use to manage the network from a single console. It abstracts
hardware elements and functions (e.g., connections, switches, routers, etc.)
➢ Software-Defined Networking (SDN) virtualizes hardware that controls network traffic routing
(called the “control plane”)
➢ Network Function Virtualization (NFV) virtualizes one or more hardware appliances that
provide a specific network function (e.g., a firewall, load balancer, or traffic analyzer), making
those appliances easier to configure, provision, and manage.
Types of virtualization (Cont.)
➢ Storage Virtualization Storage virtualization enables all the storage devices on the
network, whether they’re installed on individual servers or standalone storage units
to be accessed and managed as a single storage device. Storage virtualization
makes it easier to provision storage for VMs and makes maximum use of all
available storage on the network.
➢ Application Virtualization runs application software without installing it directly on
the user’s OS. This differs from complete desktop virtualization because only the
application runs in a virtual environment, while the OS on the end user’s device runs
as usual.
Types of virtualization (Cont.)
➢ Types of application virtualization:
• Local Application Virtualization The entire application runs on the endpoint device
but runs in a runtime environment instead of on the native hardware.
• Application Streaming The application lives on a server which sends small
components of the software to run on the end user's device when needed.
• Server-based Application Virtualization The application runs entirely on a server
that sends only its user interface to the client device.
Benefits of virtualization
➢ Resource efficiency
➢ Easier management
➢ Minimal downtime
➢ Faster provisioning