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What is Computing?

• Computing is the use of computer technology to effectively address problems or complete tasks.
• It encompasses the design, development, and construction of computer software systems.
• Computing also involves processing, structuring, and managing data for various applications and scientific research.

Computing Paradigms

• Computing paradigms include distributed, parallel, cluster, grid, utility, cloud, edge, and fog computing.

Distributed Computing

• Distributed computing involves multiple computer systems working together to solve a single problem.
• The computer systems are linked, and the problem is divided into sub-problems, each solved by a different system.
• The aim is to increase performance, efficiency, and ensure fault tolerance.

Parallel Computing

• Parallel computing uses multiple computer systems simultaneously.
• A problem is divided into sub-problems, then into instructions executed concurrently on different processors.
• This paradigm aims to save time and increase concurrency.

Cluster Computing

• Cluster computing consists of two or more tightly coupled independent computers that work together as a single machine.
• It aims to increase performance, scalability, and simplicity.

Grid Computing

• Grid computing involves a network of loosely coupled, geographically remote computers that work together on tasks too difficult for a single machine.
• The goal is to solve more high computational problems in less time and improve productivity.

Utility Computing

• Utility computing is a service provisioning model where service providers make computing resources and infrastructure management available to customers as needed, charged by usage (pay-per-use) instead of a flat rate.
• Cloud computing practically implements the concept of utility computing.

Cloud Computing

• Cloud computing delivers on-demand computing services over the internet on a pay-per-use basis.

Edge Computing

• Aims to reduce client-server communication latency by running fewer processes in the cloud and moving these processes onto a user's computer, IoT device, or edge device/server.

Fog Computing

• Fog computing acts as a computational structure between the cloud and data-producing devices.

Evolution of Cloud Computing

• Milestones include Distributed Computing (1950s), Mainframe Computing, Cluster Computing, Grid Computing, Virtualization, Web 2.0, Service Orientation, Utility Computing (2007+), and Cloud Computing.

NIST Definition of Cloud Computing

• Cloud computing is a model that allows convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services).
• These resources can be rapidly provisioned and released with minimal management effort or service provider interaction.

Essential Characteristics of Cloud Computing

• On-demand self-service: Consumers can unilaterally provision computing capabilities as needed without human interaction.
• Broad network access: Capabilities available over the network and accessed through standard mechanisms via various client platforms like mobile phones, tablets, laptops, and workstations.
• Resource pooling: Provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with dynamic assignment and reassignment of virtual and physical resources based on consumer demand.
• Rapid elasticity: Capabilities can be elastically provisioned and released to scale rapidly based on demand, sometimes automatically.
• Measured service: Cloud systems automatically control and optimize resources use via metering capabilities appropriate to the service type.

Benefits of Cloud Computing

• Lower IT costs and increased economic return.
• Improved agility and time-to-value.
• Scalability, data/resource availability for employees, and collaboration efficiency.
• Provision of new services to customers and access to automatic updates.

Challenges of Cloud Computing

• Data security and privacy.
• Multi-cloud environments.
• Performance challenges.
• Achieving interoperability and flexibility.
• Handling high dependence on network performance.
• Addressing a lack of knowledge and expertise.
• Ensuring reliability and availability.
• Maintaining password security.
• Managing costs.
• Overcoming a lack of internal expertise.
• Exercising control or governance
• Ensuring compliance.

Cloud Service Models

• Cloud service models define the types of services a cloud provider offers.
• NIST defines three basic models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).
• Besides these, specialized cloud services such as NaaS, STaaS, DBaaS, DEaaS, IDaaS, fall under XaaS (Anything as a Service).

IaaS (Infrastructure as a Service)

• IaaS delivers on-demand infrastructure resources like compute, storage, networking, and virtualization to organizations via the cloud.
• Customers don't manage the data center infrastructure but are responsible for the operating system, middleware, apps, and data.

Services Provided by IaaS Providers

• Includes compute services with virtual CPUs and memory for virtual machines (VMs).
• Storage services provide back-end storage for VM images and files.
• Network services offer virtual networking components for VMs, like virtual routers and switches.
• Load Balancers at the infrastructure layer.

Suitability for IaaS

• Unpredictable spikes in computing resources usage.
• Start-up companies with less capital investment on hardware.
• Organizations needing on-demand infrastructure for a short period.

IaaS Pros

• Highest level of control over infrastructure.
• On-demand scalability.
• No single point of failure for higher reliability.
• Reduced upfront capital expenditures, fewer provisioning delays, and accelerated development.

IaaS Cons

• Responsibility for data security and recovery.
• Requires hands-on configuration and maintenance.
• Difficulties securing legacy applications on cloud-based infrastructure.

Examples of IaaS Providers

• AWS offers a wide range of IaaS services, such as EC2 (virtual servers), S3 (storage), and VPC (networking).
• Microsoft Azure provides IaaS capabilities through services like Azure Virtual Machines, Azure Storage, and Azure Virtual Network.
• Google Cloud Platform (GCP) offers IaaS solutions like Google Compute Engine, Google Cloud Storage, and Google Virtual Private Cloud (VPC).
• IBM Cloud provides IaaS offerings, including IBM Virtual Servers, IBM Cloud Object Storage, and IBM Virtual Private Cloud (VPC).

PaaS (Platform as a Service)

• PaaS delivers and manages all hardware and software resources for developing applications via the cloud.
• Customers still write code and manage data and applications, but the cloud service provider maintains the environment.

Services Provided by PaaS Providers

• Provide a variety of programming for developers to use to develop applications
• Provide application frameworks that simplify the application development
• Offer tools to help develop, deploy and test applications
• Provide wide variety of programming languages for the developers to develop applications.
• Provides application frameworks that simplifies application development.
• Provides other tools for development, deployment and testing the application.

Suitability for PaaS

• PaaS is helpful when there is a need for:
  • collaborative development
  • automated testing and deployment
  • bringing applications to market quickly.

PaaS Pros

• Instant access to a development platform.
• The cloud service provider maintains the infrastructure.
• Available via internet Connection
• Offers and on demand scalability

PaaS Cons

• Application stack can be restrictive
• Subject to Vendor Lock-In
• Less control over operations and overall infrastructure
• Limited Customizations

Examples of PaaS Providers

• Heroku
• Microsoft Azure App Service
• Google App Engine
• AWS elastic Beanstalk
• IBM Cloud Foundry

SaaS (Software as a Service)

• SaaS delivers an entire application stack, providing cloud-based applications that customers access and use.
• all SaaS products are managed by the service provider and are ready to use
• Most SaaS applications can be access via web browser

Services Provided by SaaS Providers

• Business. Social, and Project Management Service such as:
  • ERP
  • CRM
  • HR Solutions
  • Facilitate Networking and Collaboration
  • Content sharing
  • Video conferencing
  • Tools for real time communication
  • System to create and track electronic documents
  • Email
  • Solutions to management tools

Suitability for SaaS

• Software for startups
• Software with multiple compatibility
• Short-term projects

SaaS Pros

• Easy to set up and start running
• The provider oversees everything (hardware-software)
• Can access the software with internet

SaaS Cons

• No oversight of of security or infrastructure.
• Risk of integration issues
• Vendor Lock-In
• Limited or no customization

Examples of SaaS Providers

• Google Workplace
• Microsoft 365
• Adobe Creative Cloud
• Salesforce

Cloud Deployment Models

• Define how to deliver , configure, and manager cloud services
• Specifies who managers what infrastructure.
  • NIST provides four cloud deployment models
    • Public
    • Private
    • Community
    • Hybrid

Public Cloud

• Cloud structure is provided for open use through a public Network by:
  • Government organizations
  • Businesses
  • Academics
  • Combination of all
• All exists on the premises of the cloud provider

Characteristics of Public Cloud

• Scalable with infinite Resources
• Requires Users to pay for only the resources they use, eliminating deployment cost.
• Least Secure due to third-party and data loss is high
• High Availability due to accessibility
• They follow the SLA Strictly

Public Cloud Suitability

• Large Resource Requirements
• Varying resource needs
• no Physical infrastructure
• Financial constraints on the organization.

Private Cloud

• provided for exclusive use by organization with several consumers
• Managed by an internal third party
• Existing on or off premises

Characteristics of Private Cloud

• Secure because it is managed deployable by the organization
• Full control
• Weak SLAS
• Costly

Private Cloud Suitability

• Personal or official separate cloud
• sufficient Funds
• Consider Data security important
• organizations that want autonomy and control
• less users
• pre-built infrastructure

Community Cloud

• provides to specific community of consumers from organization with shared missions, compliances, and policies.
• Can be managed by third-party
• Can exist off or on premises.

Characteristics of Community Cloud

 - collaborative with low amount of third parties
 - shared by organization with potential for data leaks
 - cost is shared 

Community Cloud Suitability

• Cloud managed with lack of control with collaboration of organizations that need enhanced securities

Hybrid Cloud

• composition with two or more cloud structure
• can combined between a community, public or private structure.
• with data portability

Characteristics of Hybrid Cloud

• scalable and secured.
• Complex for cloud management

Hybrid Cloud Suitability

• want private cloud environment with scalability of public cloud.
• require more security of public cloud.

Examples

• Public :AWS used by Netflix and Airbnb
• Private: Disney uses to control the digital property.
• Hybrid: Dropbox stores data on private server with public network offer a balance control
• Community: Health care industry allow health providers to secure patient information.