Lesson 3 - Operating System Structures

Provide an environment for execution of programs and services to programs and users

• Operating Systems

• User Interface

• Program Execution

• I/O Operations

Almost all operating systems have a user interface (UI).

• True

• False

3 Types of User Interface

• Command-Line (CLI)

• Graphics User Interface (GUI)

• Batch

• Automation

The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error).

• User Interface

• Program Execution

• I/O Operations

A running program may require I/O, which may involve a file or an I/O device.

• User Interface

• Program Execution

• I/O Operations

The file system is of particular interest.

Programs need to read and write files and directories, create and delete them, search them, list file Information, permission management.

• File-system manipulation

• Communications

• Error detection

Processes may exchange information, on the same computer or between computers over a network.

• File-system manipulation

• Communications

• Error detection

Communications may be via _____________ or through message passing (packets moved by the OS)

• Shared memory

• Virtual memory

• Communications memory

OS needs to be constantly aware of possible errors.

For each type of error, OS should take the appropriate action to ensure correct and consistent computing.

• File-system manipulation

• Communications

• Error detection

When multiple users or multiple jobs running concurrently, resources must be allocated to each of them.

• Resource allocation

• Accounting

• Protection & Security