My first Operating System Presentation
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Rida Sarwar Bilgrami's document discusses operating systems and Windows processes. It defines an operating system as an interface between hardware and users that controls computer system events. Processes are implemented as objects in Windows and can be created as new processes or copies. Both processes and threads have built-in synchronization capabilities. The document outlines several attributes of Windows process and thread objects like process ID, security descriptor, and thread context. It also describes different thread states like runnable, ready, waiting, and terminated.
My first Operating System Presentation
- 1. CreatedOn 05092013 Rida Sarwar Bilgrami B.C.S (4th Semester): Operating System: Created By: Rida Sarwar Bilgrami
- 2. CreatedOn 05092013 WINDOWS 7: An Operating System is an interface bw hardware and user, The OS control events within computer System, As a host,one of the purposes of an OS is to handle the detail of the operation of the hardware. Fundamentally we can think of the OS as that entity that manages the use of system resources by the processes. Virtual memory Computer resources Processes supported by different OS environments differ in a number of ways, including the following: 1. How Processes are named. 2. How processes are represented. 3. How process resources are protected. 4. How processes are related to each other. 5. Whether threads are provided within process. 6. What mechanism are used for inter process communication and synchronization. Created By:Rida Sarwar Bilgrami Main Memory Processor P1 P2 Pn I/O I/O
- 3. Created On05092013 Window Process Design is driven by the need to provide support for a variety of OS environments. Important characteristics of windows processes are the following: 1. Windows processes are implemented as objects. 2. A process can be created as new process, or as a copy of an existing process. 3. An executable process may contain one or more threads. 4. Both process and thread objects have built-in synchronization capabilities. Virtual Address Descriptors Handle Table Created By:Rida Sarwar Bilgrami Access Token Process Object Handle 1 Handle 2 Handle 3 . . . Thread x File y Section z
- 4. Windows Process and its resources Each Process is assigned a security access token, called the process, When a use first logs on, Windows creates an access token that includes the security ID for the user, every process that is created by or runs on behalf of this user has a copy of this access token. If the process attempts to open such a handle, the security system determines whether this is permitted and therefore whether the process may change its own attributes. Process must rely on the virtual memory manager which provides a memory allocation service for the process. The process has access to a file object and to section object that defines a section of shared memory. Process and Thread Objects: A thread is a dispatch able unit of work that executes sequentially and is interruptible, so that the processor can turn to another thread. .A Windows process must contain at least one thread to execute. Each process is defined by a number of attributes and encapsulates a no. of actions, or services that it may perform. It will perform when called upon through a set of Published Interface Methods. At a time of creation of process attribute values are assigned. Windows Process Object Attributes 1. Process ID 2. Security Descriptor 3. Base Priority 4. Default Processor Affinity 5. Quota Limits 6. Execution Time 7. IO counters 8. V M Operation counters 9. Execution /Debugging Ports 10. Exit status Windows Thread Object Attributes 1. Thread ID 2. Thread Context 3. Dynamic Priority 4. Base Priority 5. Thread processor Affinity 6. Thread Execution time 7. Alert Status 8. Suspension Count 9. Impersonation Token 10. Termination Port 11. Thread Exit Status Created On05092013 Created By:Rida Sarwar Bilgrami
- 5. Threads States RUNNABLE: Pick To Run Switch Preemted BlockSuspend Unblock Resources not available NOT RUNNABLE Ready Transitio n Stand BY Running Waiting Terminated