INTRODUCTION TO OPERATING SYSTEM
Operating System
Operating System Objectives
Layers of Computer Systems
Services Provided by the Operating System
Functions of Operating Systems
Types of Operating Systems
Enhancing an OS
Operating System Objectives
Layers of Computer System
Services Provided by the Operating System
Services Provided by the Operating System
Functions of Operating Systems
Providing a User Interface
Managing Hardware
Organizing Files and Folders
Types of Operating Systems
Introduction to Information Technology- Operating systemTrinity Dwarka
Department of computer application- Introduction to Information Technology- Operating system
Operating System
Operating System Objectives
Layers of Computer Systems
Services Provided by the Operating System
Functions of Operating Systems
Types of Operating Systems
Enhancing an OS
A program that controls the execution of application programs
An interface between applications and hardware
Layers of Computer System
Services Provided by the Operating System
Program development
Editors and debuggers
Program execution
Access to I/O devices
Controlled access to files
System access
Operating system 02 os as an extended machineVaibhav Khanna
Functions performed by the
operating systems:
Managing the hardware resources of the
computer
Providing the user-interface components
Providing a platform for software developers
to write applications
The components of an operating system all exist in order to make the different parts of a computer work together. All user software needs to go through the operating system in order to use any of the hardware, whether it be as simple as a mouse or keyboard or as complex as an Internet component.
Introduction to Information Technology- Operating systemTrinity Dwarka
Department of computer application- Introduction to Information Technology- Operating system
Operating System
Operating System Objectives
Layers of Computer Systems
Services Provided by the Operating System
Functions of Operating Systems
Types of Operating Systems
Enhancing an OS
A program that controls the execution of application programs
An interface between applications and hardware
Layers of Computer System
Services Provided by the Operating System
Program development
Editors and debuggers
Program execution
Access to I/O devices
Controlled access to files
System access
Operating system 02 os as an extended machineVaibhav Khanna
Functions performed by the
operating systems:
Managing the hardware resources of the
computer
Providing the user-interface components
Providing a platform for software developers
to write applications
The components of an operating system all exist in order to make the different parts of a computer work together. All user software needs to go through the operating system in order to use any of the hardware, whether it be as simple as a mouse or keyboard or as complex as an Internet component.
This is my sort note of operating system.In this note we describe our knowledge for B.Sc level. Student of B.Sc(H) Computer Science this note is good. We describe this note very easy language which the student easily understand.
This Tutorial will provide you information on working of operating system. Main topics are following and further sub-topics are discussed in detail.
1. Kernel Architecture.
2. Initialization of operating system.
3. Process of operating system.
4. Management in operating system.
5. File system.
6.Security in operating system.
7.Interface in operating System.
Operating System definitions and about system calls
Operating System Services
User and Operating System-Interface
System Calls
Types of system calls
System Programs
Introduction Operating system
What is Operating System
Operating System Software
main memory Management
processor management
Device Management
A brief History Of Machine
Mini computer
Super Computer
Micro Computer
Types of Operating system
Object Oriented Design
This is my sort note of operating system.In this note we describe our knowledge for B.Sc level. Student of B.Sc(H) Computer Science this note is good. We describe this note very easy language which the student easily understand.
This Tutorial will provide you information on working of operating system. Main topics are following and further sub-topics are discussed in detail.
1. Kernel Architecture.
2. Initialization of operating system.
3. Process of operating system.
4. Management in operating system.
5. File system.
6.Security in operating system.
7.Interface in operating System.
Operating System definitions and about system calls
Operating System Services
User and Operating System-Interface
System Calls
Types of system calls
System Programs
Introduction Operating system
What is Operating System
Operating System Software
main memory Management
processor management
Device Management
A brief History Of Machine
Mini computer
Super Computer
Micro Computer
Types of Operating system
Object Oriented Design
Operating System - Types Of Operating System Unit-1abhinav baba
In This Slide There is Operating System And it's types ( Types of operating system)
Batch Operating System
Network Operating System
Time Sharing Operating System
Real Time Operating System
Distributed Operating System
Basics of Operating Systems Definition – Generations of Operating systems – Types of Operating Systems, OS Service, System Calls, OS structure: Layered, Monolithic, Microkernel Operating Systems – Concept of Virtual Machine
Batch processing is a technique in which an Operating System collects the programs and data together in a batch before processing starts. An operating system does the following activities related to batch processing − The OS defines a job which has predefined sequence of commands, programs and data as a single unit.
Introduction to Operating Systems
Operating System Basics
Operating System
Operating System Objectives
Layers of Computer Systems
Services Provided by the Operating System
Functions of Operating Systems
Types of Operating Systems
Enhancing an OS
Computer Fundamentals- Classification of Digital Computers &Applications of...Trinity Dwarka
Computer Fundamentals- Classification of Digital Computers & Applications of Computers
Personal Computers
Laptops
Network Computers
Mini and Microcomputers
PDAs
Workstations
Servers
Mainframes
Supercomputers
Used at home
Used in Education Institutions and Organizations as nodes
Can perform typical activities like documentation, playing games, surfing web to more complex activities like programming, design, DTP etc.
Operating System is a software, which makes a computer to actually work.
It is the software the enables all the programs we use.
The OS organizes and controls the hardware.
OS acts as an interface between the application programs and the machine hardware.
controlling and allocating memory,
prioritizing system requests,
controlling input and output devices,
facilitating networking and
managing file systems.
EVOLUTION OF OPERATING SYSTEMS
BATCH PROCESSING
MULTI PROGRAMMING
TIME SHARING SYSTEM
Program creation
Program execution
Input/Output operations
Error detection
Resource allocation
Accounting
protection
Mobile Computing Architecture
Java-J2SE
• J2ME (Java2 Micro edition)
• JavaCard (Java for smart card)
• The Java enterprise edition (J2EE) used for web and enterprise server based applications of mobile services
C and C++
• Visual C++
• Visual Basic
Middleware for Mobile Systems
Mobile computing services Protocols
Mobile Computing Programming languages─ Java, J2ME, C/C++, Visual Basic, visual C++
OS─ Symbian OS, Window CE, Mac OS
Middleware components
Architecture software layers
Protocols layers
Network Layers
Management Information System- Information Technology ConceptsTrinity Dwarka
Management Information System- Information Technology Concepts
Recent Development in field of IT
Multimedia
Decision of appropriate information technology for MIS
Choice of appropriate IT system
Database
Database Models
Data Warehouse
Data Mining
Centralized Processing
Distributed Processing
Computer Networks- Network Basics
Network Definition
Simultaneous access to data
Shared peripheral device
Sharing Data
The Uses of Network
The Uses of a Network
Common Network Types
The operating system (OS) is the program which starts up when you turn on your computer and runs underneath all other programs - without it nothing would happen at all.
Data are raw facts and figures. Data are represented by values.
example 20,45,100 etc.
Information is processed data. It is obtained after the processin
Computer Application- Introduction to IT
Memory
Types of storage
Registers
Cache
Main Memory
RAM
ROM
Flash Memory
Secondary Storage
Magnetic Tape
Magnetic Disk
CD DVD
Pen Drive
Network Storage
SAN
DAS
NAS
Management- INTRODUCTION TO INFORMATION TECHNOLOGY
MOTHERBOARD
CPU
RAM & ROM
SRAM
DRAM
Limitation of Secondary Devices
Magnetic Tape
Magnetic Tape Types
Software Crisis
Software products:
fail to meet user requirements.
Software product
expensive.
difficult to alter, debug, and enhance.
often delivered late.
use resources non-optimally.
Factors contributing to the software crisis
Computer Systems Engineering
Software Life Cycle
Life Cycle Model
Java Programming- Introduction to Java Applet ProgramsTrinity Dwarka
Java Programming- Introduction to Java Applet Programs
Java Applets
Java Applet Classes
Contrast Application with Applet
Applet Declaration
Body of an Applet
Applets
Applets and Web Pages – HTML
Running the Applet
Department of Computer Application- Web based programming
INTERNET
WORLD WIDE WEB
WHAT ARE WEB SITES
WEB APPLICATIONS
ADVANTAGES & DISADVANTAGES OF WEB BASED APPLICATIONS
WEB APPLICATION – THREE-TIER ARCHITECTURE
THREE TIER ARCHITECTURE
WEB BASED TECHNOLOGIES
Creating VB .Net Project
Introduction to VB .Net
Creating VB .Net Project in VS 2005
Data types and Operators in VB .Net
Conditions (If Else, Select Case)
Loops (Do While, Do Until, For)
Classes, Objects
Sub routines and Functions
Features of VB .Net
Data types and Operators in VB .Net
Subroutines and Functions
Trinity Institute of Professional Studies (TIPS), ranked as one of the best Journalism College in Delhi NCR offers Bachelor of Arts in Journalism and Mass Communication (BAJMC) is a three-year undergraduate course aimed to imbibe journalistic and communication skills within the students, enabling them to prove their mettle in the media industry. It is considered as one of the best BAJMC Institute in West Delhi (Dwarka). BA JMC is a comprehensive and dynamic course, designed to enlighten students about the media industry, make them well versed with all the aspects of the field and prepare them to serve as responsible professionals. The curriculum is designed to cover both theoretical and practical subjects and provide hands-on training to the students leading to TIPS, as one of the best journalism and mass communication institutes of GGSIPU in Delhi-NCR.
Bachelor in Computer Application is one of the most popular courses among the students who want to make their career in the Information Technology area. It is a three-year undergraduate program that enhances students' knowledge and skills to meet the needs of the Information Technology (IT) industry. BCA is a course designed to give an insight to the students regarding various CS & IT concepts and their practical applications as well. TIPS, Dwarka offers excellent Placements in BCA colleges in Delhi NCR as enables students to grab promising opportunities available to them in the leading companies like Infosys, Amazon, Cognizant, Microsoft, HCL, Capgemini, Aricent, TCS, Concentrix, British Telecom, Network Bulls, IBM, and many more. The emphasis on quality and excellence has made TIPS one of the best BCA Institute of GGSIPU in Delhi NCR.
Learn More: www.tips.edu.in/bca
Principles of Management-Management-Concept & MeaningTrinity Dwarka
Principles of Management-Management-Concept & Meaning
Management- Traditional Approach
Modern Approach
Management - Meaning
Management: Nature & Characteristics
Management as an Art
Management as a Science
Importance of Management
Principles of Management- Management-Concept & Meaning
Management- Traditional Approach
Modern Approach
Management - Meaning
Management
Nature & Characteristics
Management as an Art
Management as a Science
Importance of Management
Principles of Management- Planning
Nature of Planning
Significance of Planning
Process of Planning
Limitations of Planning
Essential Requirements of an Effective Plan.
Types of Planning
Derivative Plans
Principles of Planning
Organizing Authority & Responsibility- Principles of ManagementTrinity Dwarka
Organizing Authority & Responsibility- Principles of Management
Organizing: Meaning
OrganizationcNature of Organizing
Process of Organizing
Significance of Organizing
Authority
Sources of Authority
Responsibility
Staffing- Principles of Management
Concept
Features
Nature
Scope
Sequence of activities in staffing
Principles of Staffing
Job Analysis
Recruitment
Training & Development
Directing-Principles of Management
Nature of Directing
Importance of Directing
Techniques of Directing
Directing- Motivation
Process of Motivation
Motivation Techniques
Types of Motivation
Dimensional Modelling-Data Warehouse & Data MiningTrinity Dwarka
Dimensional Modelling-Data Warehouse & Data Mining
Design Requirements
ER Modeling
Problems with ER Model
ER vs Dimensional Modeling
Dimensional Modeling:Salient Features
Dimensional Modeling: Vocabulary
Star Schema
Data Preprocessing- Data Warehouse & Data MiningTrinity Dwarka
Data Preprocessing- Data Warehouse & Data Mining
Data Quality
Reasons for inaccurate data
Reasons for incomplete data
Major Tasks in Data Preprocessing
Forms of Data Preprocessing
Data Cleaning
Incomplete (Missing) Data
Database Management System
DBMS Functionality
Main Characteristics of the Database Approach
Instances and Schemas
Data independence
The Entity-Relationship Model
Database Users
Advantages of Using the Database Approach
E-Commerce- Introduction to E-Commerce
Multistage Model for E-commerce
Search and identification
Selection and negotiation
Product and service delivery
After-sales service
Multistage Model for E-Commerce
DIGITAL ELECTRONICS- Minimization TechniqueKarnaugh MapTrinity Dwarka
DIGITAL ELECTRONICS- Minimization TechniqueKarnaugh Map
4 Variable K Map
2 Variable K Map
3 Variable K Map
K-map solution for Equation
K-map for Equation
DIGITAL ELECTRONICS- Number System
Positional Notation
Radix (Base) of a Number System
Radix (Base) of a Number System
Decimal Number Systems
Binary Number System
Decimal to Binary Conversion
Converting Decimal to Binary
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
INTRODUCTION TO OPERATING SYSTEM
1. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Affiliated Institution of G.G.S.IP.U, Delhi
BCA
OPERATING SYSTEMS
BCA 301
INTRODUCTION TO OPERATING SYSTEM
2. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Operating System Basics
• Operating System
• Operating System Objectives
• Layers of Computer Systems
• Services Provided by the Operating System
• Functions of Operating Systems
• Types of Operating Systems
• Enhancing an OS
3. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Operating System
• A program that controls the execution of
application programs
• An interface between applications and hardware
4. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Operating System Objectives
• Convenience
– Makes the computer more convenient to use
• Efficiency
– Allows computer system resources to be used in an
efficient manner
• Ability to evolve
– Permit effective development, testing, and
introduction of new system functions without
interfering with service
5. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Layers of Computer System
6. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Services Provided by the Operating
System
• Program development
– Editors and debuggers
• Program execution
• Access to I/O devices
• Controlled access to files
• System access
7. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Services Provided by the Operating
System
• Error detection and response
– internal and external hardware errors
• memory error
• device failure
– software errors
• arithmetic overflow
• access forbidden memory locations
– operating system cannot grant request of application
8. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Services Provided by the Operating
System
• Accounting
– collect statistics
– monitor performance
– used to anticipate future enhancements
– used for billing users
9. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Functions of Operating Systems
• Provide a user interface
• Run programs
• Manage hardware devices
• Organized file storage
10. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Providing a User Interface
• User interface
– How a user interacts with a computer
– Require different skill sets
11. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Providing a User Interface
• Graphical user interface (GUI)
– Most common interface
• Windows, OS X, Gnome, KDE
– Uses a mouse to control objects
– Uses a desktop metaphor
– Shortcuts open programs or documents
– Open documents have additional objects
– Task switching
– Dialog boxes allow directed input
12. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Graphical User Interface
13. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Providing a User Interface
• Command line interfaces
– Older interface
• DOS, Linux, UNIX
– User types commands at a prompt
– User must remember all commands
– Included in all GUIs
14. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Command Line Interface
15. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Running Programs
• Many different applications supported
• System call
– Provides consistent access to OS features
• Share information between programs
– Copy and paste
– Object Linking and Embedding
16. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Managing Hardware
• Programs need to access hardware
• Interrupts
– CPU is stopped
– Hardware device is accessed
• Device drivers control the hardware
17. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Organizing Files and Folders
• Organized storage
• Long file names
• Folders can be created and nested
• All storage devices work consistently
18. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Types of Operating Systems
• Real-time operating system
– Very fast small OS
– Built into a device
– Respond quickly to user input
– MP3 players, Medical devices
19. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Types of Operating Systems
• Single user/Single tasking OS
– One user works on the system
– Performs one task at a time
– MS-DOS and Palm OS
– Take up little space on disk
– Run on inexpensive computers
20. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Single Tasking
• Operating System cannot be able to take control back from
the running process/task/application
• In case if a process call an I/O Instruction then Processor
must wait for I/O instruction to complete before preceding
21. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Types of Operating Systems
• Single user/Multitasking OS
– User performs many tasks at once
– Most common form of OS
– Windows XP and OS X
– Require expensive computers
– Tend to be complex
22. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Multitasking
• Operating System can take control back from the running process and
can give it to other.
• When one job needs to wait for I/O, the processor can switch to the
other job
23. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Types of Operating Systems
• Multi user/Multitasking OS
– Many users connect to one computer
– Each user has a unique session
– UNIX, Linux, and VMS
– Maintenance can be easy
– Requires a powerful computer
24. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Multi user/Multi tasking OS
25. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Enhancing an OS
• Utilities
– Provide services not included with OS
– Goes beyond the four functions
– Firewall, anti-virus and compression
– Prices vary
26. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Enhancing an OS
• Backup software
– Archives files onto removable media
– Ensures data integrity
– Most OS include a backup package
– Many third party packages exist
27. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Backup Software
28. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Enhancing an OS
• Anti-virus software
– Crucial utility
– Finds, blocks and removes viruses
– Must be updated regularly
– McAfee and Norton Anti-Virus
29. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Enhancing an OS
• Firewall
– Crucial utility
– Protects your computer from intruders
– Makes computer invisible to hackers
– Zone Labs is a home firewall
– Cisco sells hardware firewalls
30. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Enhancing an OS
• Intrusion detection
– Often part of a firewall package
– Announces attempts to breach security
– Snort is a Linux based package
31. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Enhancing an OS
• Screen savers
– Crucial utility for command line systems
• Prevents burn in
– Merely fun for GUI systems
– Screen saver decorates idle screens