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Exam CC - Coggle Diagram
Exam CC
Q1. Objectifs & components of an IS
objectives :
Collect data from the environment
store and organize it efficiently
process it to produce useful information
distribute it to the right users at the right time
support decision-making at all levels of an organization
Components :
Hardware – physical machines, servers, network devices
Software – applications, OS, middleware
Data - the raw material processed by the IS
People – users, administrators, developers
Processes – rules and procedures for using the system
Network – infrastructure enabling communication between components
Q2 les devoirs de SI + des SI pervasifs
Distributed IS duties:
Transparency – hide complexity (location, replication, failure) from users
Openness – use standard protocols so components can interoperate
Scalability – handle growing load without redesign
Fault tolerance – continue working despite partial failures
Pervasive IS duties:
Context-awareness – adapt behavior based on user location, time, activity
Invisibility – technology must be embedded and not intrusive
Interoperability – heterogeneous devices must communicate seamlessly
Autonomy – act on behalf of the user without constant input
Q3 Les deux approches adoptés des SIs pervasif dans la découverte des services
a) Directory-based (Annuaire de services):
A central or distributed registry (like a "yellow pages") stores available services. Devices register their services and others query the directory to find them.
Example: Jini (Java), SLP (Service Location Protocol)
✅ Efficient, organized
❌ Single point of failure if centralized
b) Flooding (Inondation):
A device looking for a service broadcasts a request to all its neighbors. Each neighbor forwards it further until the service is found (like a chain reaction).
Example: Gnutella P2P protocol
✅ No central point needed, fully decentralized
❌ Generates heavy network traffic, not scalable
Q4 : Two Forms of Virtualization + Products
Server Virtualization(hardware) : Multiple virtual machines run on one physical server, each with its own OS => VMware ESXi, VirtualBox
Network Virtualization : Physical network resources are abstracted into logical virtual networks => VMware NSX, Cisco ACI
Q5. Three Approaches to Migrate to the Cloud
a ) Lift and Shift:
Move applications as-is to the cloud with no modification. Fast and cheap short-term, but doesn't exploit cloud benefits fully.
Example: Taking an on-premise web server and running it on an AWS EC2 instance unchanged.
b) Move and Improve:
Migrate the app to the cloud and make partial optimizations (e.g., use managed databases, auto-scaling). Balance between speed and optimization.
Example: Moving a monolithic app but replacing its database with Amazon RDS.
c) Transform:
Completely redesign and rebuild the application as a cloud-native solution (microservices, containers, serverless). Maximum benefit, but costly and time-consuming.
Example: Re-architecting an old ERP into microservices deployed on Kubernetes.
Three Challenges of Pervasive & Distributed Systems
Heterogeneity:
Devices have different hardware, OS, protocols and data formats. They must still communicate.
Solution: Use middleware (e.g., Web Services, REST APIs), standard protocols (HTTP, MQTT), and abstraction layers.
Security & Privacy:
Data is transmitted across open, wireless networks, making it vulnerable to interception. In pervasive systems, sensitive personal data (location, health) is constantly collected.
Solution: End-to-end encryption (TLS/SSL), authentication (OAuth), anonymization, and access control policies.
Scalability:
As the number of connected devices grows (IoT), the system must handle massive data volumes and requests without degrading performance.
Solution: Load balancing, distributed architectures (microservices), edge computing to process data close to the source, and elastic cloud resources.
Three Essential Characteristics of Cloud Computing
On-demand self-service:
A user can provision computing resources (storage, VMs) automatically, without human interaction from the provider.
Example: A developer creates a new virtual server on AWS in 2 minutes via the console, with no phone call needed.
Broad network access:
Services are available over the network and accessible from any device (laptop, phone, tablet).
Example: Google Drive files are accessible from any browser anywhere in the world.
Rapid elasticity:
Resources can scale up or down quickly based on demand, appearing unlimited to the user.
Example: An e-commerce site automatically increases its server capacity on Black Friday and reduces it afterward, paying only for what was used.
Two Attitudes Toward Cloud Computing Security réponse sur papier