COSC 80 | Midterms Flashcards
a program that controls the execution of application programs and acts as an interface between the user of a computer and the computer hardware
Operating System
a software that manages a computer’s hardware
Operating System
Operating System is the one program running at all times on the computer (usually called ____), with all else being application programs
kernel
the most important part of the operating system. It is the primary interface between the hardware and the processes of a computer
kernel
Components of a computer system
- hardware
- application programs
- operating system
- users
the central processing unit (CPU), the memory, and the I/O devices provides the basic computing resources for the system
hardware
word processors, compilers, web browsers define the ways in which these resources are used to solve users’ computing problems;
application programs
controls the hardware and coordinates its use among the various application programs for the various users
operating system
users of a computer system
users
Abstract view of the components of a computer system
user
application programs
operating system
computer hardware
Typically, operating systems have a ____ for each device controller
device driver
it understands the device controller and provides the rest of the operating system with a uniform interface to the device
device driver
General-purpose computers run most of their programs from rewritable memory, called ____ (also called ____)
main memory
RAM or Random-Access Memory
a flexible and volatile type of storage device
Main Memory
commonly is implemented in a semiconductor technology called DRAM (Dynamic Random-Access Memory)
Main Memory
a semiconductor technology called ____
DRAM (Dynamic Random-Access Memory)
this instruction moves a byte or word from main memory to an internal register within the CPU
load instruction
this instruction moves the content of a register to main memory
store instruction
An Operating system is a ____. The system’s CPU, memory space, file-storage space, and I/O devices are among the resources that the operating system must manage
resource manager
Resource Management in OS
- Process Management
- Memory Management
- File-System Management
- Mass-Storage Management
- Cache Management
- I/O System Management
A ___ is a program in execution.
* A program such as compiler is a ___;
* A word-processing program being run by an individual user on a PC is a ___
process
A process needs certain ___– it includes CPU time, memory, files, and I/O devices–to accomplish its task.
* These ___ are typically allocated to the process while it is running.
* In addition to the physical and logical resources that a process obtains when it is created, various initialization data (input) may be passed along.
resources
A program is a ___, like the contents of a file stored on disk, whereas a process is an ___.
* The execution of such a process must be sequential.
* The CPU executes one instruction of the process after another, until the process completes
passive entity
active entity
A ___ is the unit of work in a system. A system consists of collection of processes, some of which are operating-system processes and the rest of which are user processes.
process
___ is central to the operation of a modern computer system.
* ___ is a repository of quickly accessible data shared by the CPU and I/O devices.
* The ____ is generally the only large storage device that the CPU is able to address and access directly
Main Memory
To improve both the utilization of the CPU and the speed of the computer’s response to its users, general-purpose computers must keep several programs in memory, creating a need for ____
memory management
____ is one of the most visible components of an operating system
File Management
in file management, physical media such as __ is the most common, but ___ is also possible
secondary storage
tertiary storage
A ___ is a collection of related information defined by its creator.
* Commonly, ___ represent programs (both source and object forms) and data.
file
___ may be numeric, alphabetic, alphanumeric or binary
Data files
Files may be __ like text files or formatted rigidly such as mp4 file format
free-form
Most modern computer systems use ___ as the principal on-line storage media for both programs and data.
* Most programs – including compilers, web browsers, word processors, and games – are stored on these devices until loaded into memory.
HDDs and NVM devices
Since secondary storage is used frequently and extensively, it must be used ___.
* The entire speed of operation of a computer may hinge on the speeds of the secondary storage sub-system and the algorithms that manipulate that sub-system
efficiently
___ is an important principle of computer systems. In ___, information is normally kept in some storage system (such as main memory).
* As it is used, it is copied into a faster storage system – the __ - on a temporary basis.
Caching
Cache
Because caches have limited size, ___ is an important design problem.
* Careful selection of the cache size and of a replacement policy can result in greatly increased performance
cache management
One of the purposes of an operating system is to hide the peculiarities of specific hardware devices from the user.
For example, in UNIX, the peculiarities of I/O devices are hidden from the bulk of the operating system itself by the ___.
I/O subsystem
this type of operating system does not interact with the computer directly
Batch Operating System
An __ is present which takes similar jobs having the same requirement and groups them into batches
operator
___ can be illustrated as more than one program is present in the main memory and any of them can be kept in execution.
* As a result, various jobs may share CPU time.
Multiprogramming Operating Systems
___ is a type of operating system in which more than one CPU is used for the execution of resources
Multiprocessing Operating System
___ is simply a multiprogramming operating system with having facility of a Round-Robin Scheduling Algorithm.
* It can run multiple programs simultaneously
Multitasking Operating System
___ – each task is given some time to execute so that all the tasks work smoothly.
* Each user gets the time of the CPU as they use a single system.
* The task can be from a single user or different users
Time-Sharing Operating Systems
___ – it uses many central processors to serve multiple real-time applications and users.
* Independent systems process their own memory unit and CPU
Distributed Operating System
___ – These systems run on a server and provide the capability to manage data, users, groups, security, applications, and other networking functions.
* These types of operating systems allow shared access to files, printers, security, applications, and other networking functions over a small private network.
Network Operating System
it provides an environment for the execution of programs
operating system
One set of operating system services provides functions that are helpful to the user:
- user interface
- program execution
- i/o operations
- file-system manipulation
- communications
- error detection
Another set of operating-system functions is for ensuring the efficient operation of the system itself:
- resource allocation
- logging
- protection and security
The interface is a window system with a mouse that servers as a pointing device to direct I/O, choose from menus, and make selections and a keyboard to enter text
graphical user interface
it uses text commands and a method for entering them is also another option
command-line interface
The system must be able to load a program into memory and to run that program. The program must be able to end its execution, either normally or abnormally.
program execution
A running program may require I/O, which may involve a file or an I/O device. For specific devices, special functions may be desired (such as reading from a network interface or writing to a file system). For efficiency and protection, users usually cannot control I/O devices directly. Therefore, the operating system must provide a means to do I/O
I/O operations
Programs need to read and write files and directories. They also need to create and delete them by name, search for a given file, and list file information. Finally, some operating systems include permissions management to allow or deny access to files or directories based on file ownership
file-system manipulation