Chapter 1 - Introduction Flashcards
What is an operating system?
An operating system is software that manages the computer hardware, as well as providing an environment for application programs to run.
What are interrupts?
Interrupts are a key way in which hardware interacts with the operating system. A hardware device triggers an interrupt by sending a signal to the CPU to alert the CPU that some event requires attention. The interrupt is managed by the interrupt handler.
Where should programs be in order for a computer to do its job?
For a computer to do its job of executing programs, the programs must be in main memory, which is the only large storage area that the processor can access directly.
What is the main memory?
The main memory is usually a volatile storage device that loses its contents when power is turned off or lost.
What is a nonvolatile storage?
Nonvolatile storage is an extension of main memory and is capable of holding large quantities of data permanently.
What is the most common nonvolatile storage device?
The most common nonvolatile storage device is a hard disk, which can provide storage of both programs and data.
What processor system do modern computers have?
Modern computer architectures are multiprocessor systems in which each CPU contains several computing cores.
What system do modern operating systems employ to best utilize the CPU?
To best utilize the CPU, modern operating systems employ multiprogramming, which allows several jobs to be in memory at the same time, thus ensuring that the CPU always has a job to execute.
What is multitasking?
Multitasking is an extension of multiprogramming wherein CPU scheduling algorithms rapidly switch between processes, providing users with a fast response time.
What are the two modes?
To prevent user programs from interfering with the proper operation of the system, the system hardware has two modes: user mode and kernel mode.
List some examples of privileged instructions.
Various instructions are privileged and can be executed only in kernel mode. Examples include the instruction to switch to kernel mode, I/O control, timer management, and interrupt management.
What is a process?
A process is the fundamental unit of work in an operating system. Process management includes creating and deleting processes and providing mechanisms for processes to communicate and synchronize with each other.
How does an operating system manage memory?
An operating system manages memory by keeping track of what parts of memory are being used and by whom. It is also responsible for dynamically allocating and freeing memory space.
What is storage space managed by?
Storage space is managed by the operating system; this includes providing file systems for representing files and directories and managing space on mass-storage devices.
What is virtualization?
Virtualization involves abstracting a computer’s hardware into several different execution environments.
