Master sequence diagrams with this sequence diagram guide. It describes everything you need to know on sequence diagram notations, best practices as well as common mistakes. It also explains how to draw a sequence diagram step by step. Plus it offers Creately sequence diagram templates you can click and edit right away.
This document discusses memory management and paging in operating systems. It explains that memory management allocates space for application routines and prevents interference between programs. The memory hierarchy includes main memory, cache memory, and secondary storage. Paging is a memory management technique that divides processes and main memory into equal pages. It allows processes to be non-contiguous in memory. The operating system uses page tables to map logical addresses to physical addresses stored across different pages and frames. Paging reduces external fragmentation but can cause internal fragmentation.
The document discusses the thread model of Java. It states that all Java class libraries are designed with multithreading in mind. Java uses threads to enable asynchronous behavior across the entire system. Once started, a thread can be suspended, resumed, or stopped. Threads are created by extending the Thread class or implementing the Runnable interface. Context switching allows switching between threads by yielding control voluntarily or through prioritization and preemption. Synchronization is needed when threads access shared resources using monitors implicit to each object. Threads communicate using notify() and wait() methods.
This document discusses memory management techniques used in operating systems, including:
- Base and limit registers that define the logical address space and protect memory accesses.
- Address binding from source code to executable addresses at different stages.
- The memory management unit (MMU) that maps virtual to physical addresses using base/limit registers.
- Segmentation architecture that divides memory into logical segments like code, data, stack, heap.
This document discusses transaction management and concurrency control. It defines a transaction as a logical unit of work that must be completed or aborted with no intermediate states. It describes the ACID properties of atomicity, consistency, isolation, and durability that transactions should have. It also discusses concurrency control techniques like locking and time stamping to ensure transactions execute serially for consistency despite concurrent access.
This document discusses key aspects of distributed file systems including file caching schemes, file replication, and fault tolerance. It describes different cache locations, modification propagation techniques, and methods for replica creation. File caching schemes aim to reduce network traffic by retaining recently accessed files in memory. File replication provides increased reliability and availability through independent backups. Distributed file systems must also address being stateful or stateless to maintain information about file access and operations.
El documento describe las arquitecturas de software de varios niveles. Explica que una arquitectura de varias capas separa la presentación, la lógica del negocio y los datos en componentes distintos. Esto permite cambiar cada capa con menos impacto en las otras y favorece la extensibilidad y reutilización del software. Se mencionan ejemplos de arquitecturas físicas de dos y tres niveles que despliegan las capas lógicas en nodos separados.
Processes communicate through interprocess communication (IPC) using two main models: shared memory and message passing. Shared memory allows processes to access the same memory regions, while message passing involves processes exchanging messages through mechanisms like mailboxes, pipes, signals, and sockets. Common IPC techniques include semaphores, shared memory, message queues, and sockets that allow processes to synchronize actions and share data in both blocking and non-blocking ways. Deadlocks can occur if processes form a circular chain while waiting for resources held by other processes.
Master sequence diagrams with this sequence diagram guide. It describes everything you need to know on sequence diagram notations, best practices as well as common mistakes. It also explains how to draw a sequence diagram step by step. Plus it offers Creately sequence diagram templates you can click and edit right away.
This document discusses memory management and paging in operating systems. It explains that memory management allocates space for application routines and prevents interference between programs. The memory hierarchy includes main memory, cache memory, and secondary storage. Paging is a memory management technique that divides processes and main memory into equal pages. It allows processes to be non-contiguous in memory. The operating system uses page tables to map logical addresses to physical addresses stored across different pages and frames. Paging reduces external fragmentation but can cause internal fragmentation.
The document discusses the thread model of Java. It states that all Java class libraries are designed with multithreading in mind. Java uses threads to enable asynchronous behavior across the entire system. Once started, a thread can be suspended, resumed, or stopped. Threads are created by extending the Thread class or implementing the Runnable interface. Context switching allows switching between threads by yielding control voluntarily or through prioritization and preemption. Synchronization is needed when threads access shared resources using monitors implicit to each object. Threads communicate using notify() and wait() methods.
This document discusses memory management techniques used in operating systems, including:
- Base and limit registers that define the logical address space and protect memory accesses.
- Address binding from source code to executable addresses at different stages.
- The memory management unit (MMU) that maps virtual to physical addresses using base/limit registers.
- Segmentation architecture that divides memory into logical segments like code, data, stack, heap.
This document discusses transaction management and concurrency control. It defines a transaction as a logical unit of work that must be completed or aborted with no intermediate states. It describes the ACID properties of atomicity, consistency, isolation, and durability that transactions should have. It also discusses concurrency control techniques like locking and time stamping to ensure transactions execute serially for consistency despite concurrent access.
This document discusses key aspects of distributed file systems including file caching schemes, file replication, and fault tolerance. It describes different cache locations, modification propagation techniques, and methods for replica creation. File caching schemes aim to reduce network traffic by retaining recently accessed files in memory. File replication provides increased reliability and availability through independent backups. Distributed file systems must also address being stateful or stateless to maintain information about file access and operations.
El documento describe las arquitecturas de software de varios niveles. Explica que una arquitectura de varias capas separa la presentación, la lógica del negocio y los datos en componentes distintos. Esto permite cambiar cada capa con menos impacto en las otras y favorece la extensibilidad y reutilización del software. Se mencionan ejemplos de arquitecturas físicas de dos y tres niveles que despliegan las capas lógicas en nodos separados.
Processes communicate through interprocess communication (IPC) using two main models: shared memory and message passing. Shared memory allows processes to access the same memory regions, while message passing involves processes exchanging messages through mechanisms like mailboxes, pipes, signals, and sockets. Common IPC techniques include semaphores, shared memory, message queues, and sockets that allow processes to synchronize actions and share data in both blocking and non-blocking ways. Deadlocks can occur if processes form a circular chain while waiting for resources held by other processes.
Deadlock in distribute system by saeed siddikSaeed Siddik
The document discusses deadlocks in distributed systems, outlining the four conditions required for a deadlock, strategies to handle deadlocks such as ignoring, detecting, preventing, and avoiding them, and algorithms for centralized deadlock detection and distributed deadlock detection and prevention. It provides examples of resource allocation graphs to illustrate deadlock conditions and explains how distributed deadlock detection and prevention algorithms work.
How to find Candidate keys , Minimal Keys and CLosure of any Attributes?Mohd Aasif
This document discusses key concepts in database normalization including functional dependencies, minimal keys, candidate keys, and how to find the closure and candidate keys of attributes. It provides examples and steps to determine if a set of attributes is a candidate key, which is a minimal set that uniquely identifies tuples. For a sample relation with attributes A, B, C, D, E, F and functional dependencies, it shows that AF is the only candidate key since its closure includes all attributes and it is the minimum set.
Este documento describe los pasos para configurar Rundeck y Jenkins para automatizar tareas. Se configura Rundeck en una máquina, se agregan nodos, y se crean proyectos y jobs para ejecutar comandos en los nodos de forma remota. Luego, se integra Rundeck con Jenkins mediante un plugin, y se crea un job de Jenkins que ejecuta un job de Rundeck después de cada compilación con éxito.
Deadlock avoidance methods analyze resource allocation to determine if granting a request would lead to an unsafe state where deadlock could occur. A deadlock happens when multiple processes are waiting indefinitely for resources held by each other in a cyclic dependency. To prevent deadlock, an operating system must have information on current resource availability and allocations, as well as future resource needs. The system only grants requests that will lead to a safe state where there are enough resources for all remaining processes and deadlock is not possible.
IGNOU BCS-051 Software Engineering December 2022 - Exam Solutions.docxAnilVhatkar
The document describes requirements for an Online Examination Form Submission System (OEFSS) according to the IEEE format, including developing a software requirements specification, explaining the prototype model of software development with an example, providing a structure chart to decompose a system into executable tasks using a hotel billing system as an example, and presenting a Gantt chart showing the tasks, dependencies, and time estimates for developing the OEFSS.
The Dining Philosopher Problem – The Dining Philosopher Problem states that K philosophers seated around a circular table with one chopstick between each pair of philosophers. There is one chopstick between each philosopher. A philosopher may eat if he can pick up the two chopsticks adjacent to him.
This document discusses semaphores and their use in solving critical section problems. It defines semaphores, describes their wait and signal methods, and types including counting and binary semaphores. It then explains how semaphores can be used to solve classical synchronization problems like the bounded buffer, readers-writers, and dining philosophers problems. Examples of semaphore implementations are provided for each problem.
Chapter 12 transactions and concurrency controlAbDul ThaYyal
This document provides an overview and summary of key concepts related to transactions and concurrency control in distributed systems:
- Transactions allow a sequence of operations to be atomic and isolated despite crashes or concurrent operations. They ensure objects remain in a consistent state.
- Concurrency control techniques like locking and timestamp ordering ensure transactions are isolated and avoid problems like lost updates or inconsistent retrievals that could occur without synchronization.
- Transactions must commit atomically so their effects are durable even after crashes, or abort with no effect. Serializability ensures transactions have an effect equivalent to running serially one at a time.
Independent processes operate concurrently without affecting each other, while cooperating processes can impact one another. Inter-process communication (IPC) allows processes to share information, improve computation speed, and share resources. The two main types of IPC are shared memory and message passing. Shared memory uses a common memory region for fast communication, while message passing involves establishing communication links and exchanging messages without shared variables. Key considerations for message passing include direct vs indirect communication and synchronous vs asynchronous messaging.
Allocation of processors to processes in Distributed Systems. Strategies or algorithms for processor allocation. Design and Implementation Issues of Strategies.
This document discusses event handling in Java. It covers using the delegation event model, handling keyboard and mouse events, and using adapter classes. Key points covered include implementing the appropriate interface for the event desired, registering the listener, and providing empty implementations in adapter classes to simplify creating event handlers. Examples are provided to demonstrate handling keyboard and mouse events.
1) A thread is a flow of execution within a process that has its own program counter, registers, and stack. Threads allow for parallelism and improved performance over single-threaded processes.
2) Multithreaded processes allow multiple parts of a program to execute concurrently using multiple threads, whereas single-threaded processes execute instructions in a single sequence.
3) There are two main types of threads: user-level threads managed by a user-space thread library, and kernel-level threads directly supported by the operating system kernel. Kernel threads can take advantage of multiprocessors but have more overhead than user-level threads.
The document describes the dining philosophers problem where philosophers share a circular table to eat rice with chopsticks. Each philosopher must pick up the two chopsticks next to them to eat, but only one chopstick can be picked up at a time to avoid deadlock situations. Solutions involve limiting the number of philosophers eating simultaneously or ensuring both chopsticks are available before picking up.
There are three main methods for dealing with deadlocks in an operating system: prevention, avoidance, and detection with recovery. Prevention ensures that the necessary conditions for deadlock cannot occur through restrictions on resource allocation. Avoidance uses additional information about future resource needs and requests to determine if allocating resources will lead to an unsafe state. Detection identifies when a deadlock has occurred, then recovery techniques like process termination or resource preemption are used to resolve it. No single approach is suitable for all resource types, so systems often combine methods by applying the optimal one to each resource class.
This document discusses different types of mainframe systems, beginning with batch systems where users submit jobs offline and jobs are run sequentially in batches. It then describes multiprogrammed systems which allow multiple jobs to reside in memory simultaneously, improving CPU utilization. Finally, it covers time-sharing systems which enable interactive use by multiple users at once through very fast switching between programs, minimizing response time. The key difference between multiprogrammed and time-sharing systems is the prioritization of maximizing CPU usage versus minimizing response time respectively.
Deadlock in distribute system by saeed siddikSaeed Siddik
The document discusses deadlocks in distributed systems, outlining the four conditions required for a deadlock, strategies to handle deadlocks such as ignoring, detecting, preventing, and avoiding them, and algorithms for centralized deadlock detection and distributed deadlock detection and prevention. It provides examples of resource allocation graphs to illustrate deadlock conditions and explains how distributed deadlock detection and prevention algorithms work.
How to find Candidate keys , Minimal Keys and CLosure of any Attributes?Mohd Aasif
This document discusses key concepts in database normalization including functional dependencies, minimal keys, candidate keys, and how to find the closure and candidate keys of attributes. It provides examples and steps to determine if a set of attributes is a candidate key, which is a minimal set that uniquely identifies tuples. For a sample relation with attributes A, B, C, D, E, F and functional dependencies, it shows that AF is the only candidate key since its closure includes all attributes and it is the minimum set.
Este documento describe los pasos para configurar Rundeck y Jenkins para automatizar tareas. Se configura Rundeck en una máquina, se agregan nodos, y se crean proyectos y jobs para ejecutar comandos en los nodos de forma remota. Luego, se integra Rundeck con Jenkins mediante un plugin, y se crea un job de Jenkins que ejecuta un job de Rundeck después de cada compilación con éxito.
Deadlock avoidance methods analyze resource allocation to determine if granting a request would lead to an unsafe state where deadlock could occur. A deadlock happens when multiple processes are waiting indefinitely for resources held by each other in a cyclic dependency. To prevent deadlock, an operating system must have information on current resource availability and allocations, as well as future resource needs. The system only grants requests that will lead to a safe state where there are enough resources for all remaining processes and deadlock is not possible.
IGNOU BCS-051 Software Engineering December 2022 - Exam Solutions.docxAnilVhatkar
The document describes requirements for an Online Examination Form Submission System (OEFSS) according to the IEEE format, including developing a software requirements specification, explaining the prototype model of software development with an example, providing a structure chart to decompose a system into executable tasks using a hotel billing system as an example, and presenting a Gantt chart showing the tasks, dependencies, and time estimates for developing the OEFSS.
The Dining Philosopher Problem – The Dining Philosopher Problem states that K philosophers seated around a circular table with one chopstick between each pair of philosophers. There is one chopstick between each philosopher. A philosopher may eat if he can pick up the two chopsticks adjacent to him.
This document discusses semaphores and their use in solving critical section problems. It defines semaphores, describes their wait and signal methods, and types including counting and binary semaphores. It then explains how semaphores can be used to solve classical synchronization problems like the bounded buffer, readers-writers, and dining philosophers problems. Examples of semaphore implementations are provided for each problem.
Chapter 12 transactions and concurrency controlAbDul ThaYyal
This document provides an overview and summary of key concepts related to transactions and concurrency control in distributed systems:
- Transactions allow a sequence of operations to be atomic and isolated despite crashes or concurrent operations. They ensure objects remain in a consistent state.
- Concurrency control techniques like locking and timestamp ordering ensure transactions are isolated and avoid problems like lost updates or inconsistent retrievals that could occur without synchronization.
- Transactions must commit atomically so their effects are durable even after crashes, or abort with no effect. Serializability ensures transactions have an effect equivalent to running serially one at a time.
Independent processes operate concurrently without affecting each other, while cooperating processes can impact one another. Inter-process communication (IPC) allows processes to share information, improve computation speed, and share resources. The two main types of IPC are shared memory and message passing. Shared memory uses a common memory region for fast communication, while message passing involves establishing communication links and exchanging messages without shared variables. Key considerations for message passing include direct vs indirect communication and synchronous vs asynchronous messaging.
Allocation of processors to processes in Distributed Systems. Strategies or algorithms for processor allocation. Design and Implementation Issues of Strategies.
This document discusses event handling in Java. It covers using the delegation event model, handling keyboard and mouse events, and using adapter classes. Key points covered include implementing the appropriate interface for the event desired, registering the listener, and providing empty implementations in adapter classes to simplify creating event handlers. Examples are provided to demonstrate handling keyboard and mouse events.
1) A thread is a flow of execution within a process that has its own program counter, registers, and stack. Threads allow for parallelism and improved performance over single-threaded processes.
2) Multithreaded processes allow multiple parts of a program to execute concurrently using multiple threads, whereas single-threaded processes execute instructions in a single sequence.
3) There are two main types of threads: user-level threads managed by a user-space thread library, and kernel-level threads directly supported by the operating system kernel. Kernel threads can take advantage of multiprocessors but have more overhead than user-level threads.
The document describes the dining philosophers problem where philosophers share a circular table to eat rice with chopsticks. Each philosopher must pick up the two chopsticks next to them to eat, but only one chopstick can be picked up at a time to avoid deadlock situations. Solutions involve limiting the number of philosophers eating simultaneously or ensuring both chopsticks are available before picking up.
There are three main methods for dealing with deadlocks in an operating system: prevention, avoidance, and detection with recovery. Prevention ensures that the necessary conditions for deadlock cannot occur through restrictions on resource allocation. Avoidance uses additional information about future resource needs and requests to determine if allocating resources will lead to an unsafe state. Detection identifies when a deadlock has occurred, then recovery techniques like process termination or resource preemption are used to resolve it. No single approach is suitable for all resource types, so systems often combine methods by applying the optimal one to each resource class.
This document discusses different types of mainframe systems, beginning with batch systems where users submit jobs offline and jobs are run sequentially in batches. It then describes multiprogrammed systems which allow multiple jobs to reside in memory simultaneously, improving CPU utilization. Finally, it covers time-sharing systems which enable interactive use by multiple users at once through very fast switching between programs, minimizing response time. The key difference between multiprogrammed and time-sharing systems is the prioritization of maximizing CPU usage versus minimizing response time respectively.