Full transcript
0:01hello and welcome to my youtube channel
0:03this video is a part of operating
0:05systems video course
0:06today's topic is services in operating
0:09systems OS services an operating system
0:14provides an environment for the
0:16execution of programs it provides
0:18certain services to programs and to the
0:21users of those programs these operating
0:24system services are provided for the
0:26convenience of the programmer to make
0:29the programming tasks easier operating
0:32system services provide following
0:35functions first user interface second
0:39program execution third file system
0:42manipulation fourth IU operation fifth
0:46communication sixth error detection
0:50seventh resource allocation eighth
0:54accounting ninth prediction and security
1:00user interface almost all operating
1:04systems have a user interface this
1:06interface can take several forms CLI
1:09which is command line interface batch
1:11interface and Gy which is a graphical
1:14user interface CLI command line
1:18interface command line interface uses
1:21text commands and a method for entering
1:23them see a keyboard for typing in
1:25commands in a specific format with
1:28specific options batch interface another
1:32is a batch interface in which commands
1:34are entered into files and those files
1:37are executed like shell scripting GUI
1:42graphical user interface most commonly
1:45used is a graphical user interface here
1:49the interface is a window with a
1:51pointing device to direct IO choose from
1:54menus and make selections and a keyboard
1:57to enter text program execution the
2:02system must be able to load a program
2:04into memory and to run that program the
2:07program must be able to end its
2:09execution either normally or abnormally
2:11indicating
2:14are you operations a running program may
2:18require IO which may involve a file or
2:20an IO device for specific devices
2:25special functions may be desired such as
2:28recording to a CD or DVD drive for
2:31efficiency and protection users usually
2:34cannot control IO devices directly
2:35therefore the operating system must
2:38provide a means to do I you file system
2:43manipulation programs need to read and
2:46write files and directories they also
2:49need to create and delete them by name
2:51search for a given file and a list file
2:54information finally some operating
2:57systems include permission management to
2:59allow or deny access to files or
3:01directories based on file ownership
3:06communications there are many
3:08circumstances in which one process needs
3:11to exchange information with another
3:13process such information may occur
3:16between processes that are executing on
3:18the same computer or between processes
3:21that are executing on different
3:23computers tied together by a computer
3:25network communication may be implemented
3:28by a shared memory or message passing
3:32error detection the operating system
3:36needs to be detecting and correcting
3:38errors constantly errors may occur in
3:41the CPU and memory hardware in IO
3:43devices and in the user program such as
3:46a resume attic overflow or an attempt to
3:49access an illegal memory location for
3:52each type of error the operating system
3:55should take the appropriate action to
3:57ensure correct and consistent computing
4:01sometimes OS has no choice but to hold
4:04the system at other times it might
4:07terminate the process to return an error
4:10code through a process to detect and
4:12possible a correct resource allocation
4:16when there are multiple users or
4:18multiple jobs running at the same time
4:20resources must be allocated to each of
4:23them the operating system manages
4:26different type of resources some may
4:29have special allocation code whereas
4:31others may have much more general
4:33requests and release code there may also
4:36be routines to allocate printers USB
4:38storage drives and other peripheral
4:41devices accounting we want to keep track
4:45of which users use how much and what
4:47kind of computer resources this
4:50record-keeping may be used for
4:52accounting so that users can be billed
4:54or simply for accumulating usage
4:56statistics protection and security the
5:01owners of information stored in
5:03multi-user or networked computer system
5:05may want to control use of that
5:07information protection involves ensuring
5:10that all access to system resources is
5:13controlled security of the system from
5:16outsiders is also important such
5:18security starts with requiring each user
5:21to authenticate himself or herself to
5:23the system usually by means of password
5:26to gain access to the system resources
5:28if a system is to be protected in secure
5:31precautions must be instituted
5:33throughout it a chain is as strong as
5:35its weakest link thank you for watching
5:39this video if you have any doubts or any
5:41suggestions please do comment do not
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5:48you