Asynchronous System Calls in Operating Systems

What is a downside of running multiple processes in a platform?

Higher memory footprint

Why is it hard/costly to maintain shared state across processes?

Due to IPC constraints

What is a high cost associated with running different processes?

Context switch

Why might it be difficult to have multiple processes listening on a specific port?

Port availability conflicts Signup and view all the answers

What approach can achieve concurrency within a single address space?

Multithreaded approach Signup and view all the answers

What setup could involve a boss running the first step and workers executing the remaining steps?

'Boss/Workers' setup Signup and view all the answers

What is the main benefit of having a execution context processing multiple requests?

Reduced latency Signup and view all the answers

Why might threads be useful on a single CPU according to the text?

To hide latency Signup and view all the answers

What happens in the event-driven model when a request needs to wait for an action?

The execution context switches to another request Signup and view all the answers

How does the event-driven model handle multiple requests within a single execution context?

By interleaving processing of multiple requests Signup and view all the answers

What can happen if a thread spends more time idle than the time it takes to context switch twice?

Context switch to another thread Signup and view all the answers

In the event-driven model, what determines when the execution context switches from one request to another?

When a request needs to wait Signup and view all the answers

What does asynchronous system calls allow the process or thread to do?

Continue execution now and check results later Signup and view all the answers

Why is a multithreaded kernel required for asynchronous calls?

To allow another kernel thread to handle waiting for I/O results Signup and view all the answers

What type of model does Apache use?

Multiprocess and multithreaded Signup and view all the answers

What benefits can hardware devices provide in asynchronous operations?

Allowing a thread to pass requests and get results at a later time Signup and view all the answers

How is the flow of control in Apache similar to the event driven model?

Each request passes through all modules Signup and view all the answers

In the absence of asynchronous I/O calls, what is needed for handling blocking I/O operations?

Helpers that interact with the dispatcher Signup and view all the answers

What does each instance in Apache represent?

A process Signup and view all the answers

How do synchronous I/O operations differ from asynchronous I/O operations?

Asynchronous operations do not block execution until results are ready Signup and view all the answers

How can the total number of processes in Apache be adjusted?

Dynamically depending on factors like outstanding requests Signup and view all the answers

What is the purpose of using helpers in handling blocking I/O operations?

To pass calls to the operation to a helper while handler returns to event dispatcher Signup and view all the answers

What is the purpose of mounting various modules in an Apache deployment?

To extend the functionality of the basic server behavior Signup and view all the answers

What is the purpose of caching in the context of the text?

To optimize performance by storing and reusing computed results. Signup and view all the answers

Which type of configuration does Apache implement with its instances?

Multithreaded boss/workers configuration Signup and view all the answers

How does caching relate to HTTP headers according to the text?

Caching can be done based on file dependency in HTTP headers. Signup and view all the answers

What does the Apache web server core component provide?

Essential server functionalities for web hosting. Signup and view all the answers

Why is it important to cache the response header according to the text?

To avoid repeated calculations of header values when the file remains unchanged. Signup and view all the answers

In what scenario would caching be most beneficial?

When repeated computations can be avoided by reusing stored results. Signup and view all the answers

How does Flash optimize performance according to the text?

By caching and utilizing available network hardware. Signup and view all the answers