Podcast
Questions and Answers
What is the primary purpose of time sharing in computing?
What is the primary purpose of time sharing in computing?
- To improve the performance of a single-user system.
- To let multiple users share the same computer system concurrently. (correct)
- To allow multiple users to use different computer systems simultaneously.
- To enable a single user to access multiple systems without delay.
How does buffering work in the context of speed differences between operations?
How does buffering work in the context of speed differences between operations?
- It slows down faster operations to match the slower ones.
- It prevents slower operations from causing delays in faster operations. (correct)
- It eliminates the need for any operational delays.
- It exclusively allows the faster operation to proceed without interruption.
Which scenario best illustrates zero capacity buffering?
Which scenario best illustrates zero capacity buffering?
- A cashier pausing while the bagger finishes their first item.
- A cashier scanning items without a bagger present. (correct)
- A cashier placing items into a full basket, waiting for space.
- A cashier continuously scanning while the bagger works at their pace.
What does bounded capacity refer to in buffering?
What does bounded capacity refer to in buffering?
What happens with unbounded capacity buffering?
What happens with unbounded capacity buffering?
In the example of buffering, who represents the CPU?
In the example of buffering, who represents the CPU?
What would be a consequence of having zero capacity buffering during a checkout?
What would be a consequence of having zero capacity buffering during a checkout?
What is a key characteristic of time sharing that distinguishes it from simple multiprogramming?
What is a key characteristic of time sharing that distinguishes it from simple multiprogramming?
What is the primary function of an operating system?
What is the primary function of an operating system?
What happens first in the sequence of interrupts when a key is pressed?
What happens first in the sequence of interrupts when a key is pressed?
What does the CPU do after acknowledging the keyboard interrupt?
What does the CPU do after acknowledging the keyboard interrupt?
In the context of interrupts, what does the interrupt vector do?
In the context of interrupts, what does the interrupt vector do?
What is the final step in the sequence of interrupts?
What is the final step in the sequence of interrupts?
What occurs during a supervisor call?
What occurs during a supervisor call?
What is the role of interrupts in a computer system?
What is the role of interrupts in a computer system?
Which of the following best describes how a CPU processes an interrupt from a keyboard?
Which of the following best describes how a CPU processes an interrupt from a keyboard?
What is the first step the operating system takes when a file copy command is issued?
What is the first step the operating system takes when a file copy command is issued?
In which mode can applications run with limited permissions to avoid affecting critical system parts?
In which mode can applications run with limited permissions to avoid affecting critical system parts?
What analogy describes the OS checking permissions for accessing a file?
What analogy describes the OS checking permissions for accessing a file?
What is the primary function of spooling in operating systems?
What is the primary function of spooling in operating systems?
Why is it important for the OS to keep programs from running in kernel mode at all times?
Why is it important for the OS to keep programs from running in kernel mode at all times?
What is meant by multiprogramming in the context of operating systems?
What is meant by multiprogramming in the context of operating systems?
What does the term 'monitor mode' refer to in operating systems?
What does the term 'monitor mode' refer to in operating systems?
How does the OS ensure that the CPU is always engaged when performing multiple tasks?
How does the OS ensure that the CPU is always engaged when performing multiple tasks?
Study Notes
Interrupts
- Interrupts are signals that interrupt the CPU's current task to handle something more urgent.
- They are often triggered by Input/Output (I/O) devices like keyboards, mouse or other peripherals.
Interrupt Sequence
- Device Sends Interrupt - An I/O device notifies the CPU of an event, e.g., a key press.
- CPU Acknowledges - The CPU pauses its current task and acknowledges the interrupt.
- Device Sends Interrupt Vector - The device sends a code (interrupt vector) identifying the specific event, e.g., a keyboard keycode.
- CPU Saves Current State - The CPU saves the state of its current task to restore it later.
- CPU Processes the Interrupt - The CPU handles the event, e.g., displays the pressed letter on screen.
- Interrupt Handled, Return to Original Task - The CPU resumes its previous task after handling the interrupt.
Supervisor Calls (System Calls)
- Supervisor calls happen when a program requests the operating system to perform tasks that require privileged access, like interacting with hardware or accessing files.
- OS performs tasks like:
- Checking permission
- Locating the file
- Copying the file
Execution Modes
- User Mode - Programs run with limited permissions. They cannot access critical system resources directly.
- Kernel Mode (Monitor Mode) - The operating system runs in this mode, allowing full access to hardware resources and system functions.
Multiprogramming
- Multiprogramming allows the CPU to switch between multiple tasks quickly, ensuring it is always busy. This improves system efficiency.
Spooling
- Spooling allows a device like a printer to handle jobs sequentially by storing them in a queue (the spool) while it is busy with the current job.
Time Sharing
- Time sharing allows multiple users to access the same computer system simultaneously by switching between them quickly. Each user gets a small time slice of the computer's resources, creating an illusion of individual access.
Buffering
- Buffering is temporary storage for data that balances speed discrepancies between two operations.
- Zero Capacity - No buffer, the faster process waits for the slower one.
- Bounded Capacity - Limited buffer space, slower process has to wait if the buffer fills up.
- Unbounded Capacity - Infinite buffer space, faster process can continue uninterrupted regardless of the slower process speed.
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Description
This quiz explores the concepts of interrupts and supervisor calls in computer systems. Learn how the CPU manages different tasks and responds to I/O device signals. Test your knowledge on interrupt sequences and the role of system calls in operating systems.
