Download Ready queue is partitioned into separate queues

Application program : Difine the ways in which these resources are used to solve
user's computing problems.
Asymmetric multiprocessing : A multiprocessing design in which each CPU is
assigned a particular program or part of a program that it executes for the duration of
the session
Absolute code: it’s a compile that can be generated in a time where the
process will reside in memory.
Bootstrap program : a technique by which a simple computer program
activates a more complicated system of programs.
bounded-buffer assumes that there is a fixed buffer size.
Background process: Ready queue is partitioned into separate queues:
@ foreground (interactive)
@ background (batch)
Backing store: fast disk large enough to accommodate copies of all
memory images for all users; must provide direct access to these memory
images.
Clustered systems: A uses multiple CPUs to complete a task. It is
different from parallel system in that clustered system consists of two or
more individual systems tied together and share storage and are closely
linked via LAN networking.
Cashing : is an important principle of computer systems, and it’s copied
into faster storage system on a temporary basis.
Client server computing : a distributed application architecture that
partitions tasks or work loads between service providers (servers) and
service requesters, called clients
command interpreter : command line interface which allows users to
directly inter the commands to be performed by the operating system .
CPU bound process: spends more time doing computations; few very
long CPU bursts
Context switch : When CPU switches to another process, the system
must save the state of the old process and load the saved state for the new
process.
Cooperating process: can affect or be affected by the execution of
another process.
CPU Cycle : Process execution consists of a cycle of CPU execution and
I/O wait
CPU burst : process execution begins with CPU burst that is followed by
an I/O burst .
Critical section : Must guarantee that no two processes can execute wait
()and signal ()on the same semaphore at the same time
Thus, implementation becomes the critical section problem where the ..
.wait and signal code are placed in the critical section
Could now have busy waiting in critical section implementation..
CPU Scheduler: Selects from among the processes in memory that are
ready to execute, and allocates the CPU to one of them
Critical section problem : the Classical Problems of Synchronization :
Bounded-Buffer Problem..
Readers and Writers Problem..
Dining-Philosophers Problem..
Compaction: a solution to a problem of external fragmentation.
Device driver : understands the device controller and presents a
uniform interface to the device to the rest of the operating system.
Distributed systems : a collection of physically separate, possibly
heterog-neous , computer system that are networked to provide the users
with access to the various resources that the system maintains.
Debugger : a system program designed to aid the programmer in finding
and correcting bugs – to determine the cause of problem .
Default signal handler : it is available in every signal that is run by the
kernel when handling that signal.
Data section: process contains global variable
Device queues: is a set of processes waiting for an I/O device
Dispatcher : a new process is initially put in the ready queue and
it is waits there until it is selected for execution .
Degree of multiprogramming : the number of processes in memory .
Dispatch latency : Dispatcher module gives control of the CPU to the
process selected by the short-term scheduler; this involves:
# switching context
# switching to user mode
# jumping to the proper location in the user program to restart that
program
Deadlock : A set of blocked processes each holding a resource and
waiting to acquire a resource held by another process in the set.
Deadlock prevention : Restrain the ways request can be made.
Deadlock avoidance : Requires that the system has some additional a
priori information available.
Dynamic loading: a mechanism by which a computer program can use
to obtain better memory-space utilization.
Dynamic linking: involves loading the subroutines of a library into an
application program at run-time.
Demand paging: is an application of virtual memory. In a system that
uses demand paging, the operating system copies a disk page into physical
memory only if an attempt is made to access it
Executable file : a file containing a list of instructions stored on
disk .
External Fragmentation: total memory space exists to satisfy a
request, but it is not contiguous.
Foreground process: Ready queue is partitioned into separate queues:
@ foreground (interactive)
@ background (batch)
Frames: the basic method for implementing paging involves braking
physical memory into fixed-sized blocks.
Graceful degradation: Graceful degradation is the ability of a computer,
machine, electronic system or network to maintain limited functionality
even when a large portion of it has been destroyed or rendered inoperative.
Heavyweight process : a process which has one thread of control .
Heap : a memory which is dynamically allocated durning
process run time .
Interrupt : is an asynchronous signal indicating the need for attention or
a synchronous event in software indicating the need for a change in
execution.
I/O bound process : spends more time doing I/O than computations,
many short CPU bursts
Independent process : process cannot affect or be affected by the
execution of another process.
Inter‐process communication (IPC) : Mechanism for processes to
communicate and to synchronize their actions .
I/O burst: process execution begins with CPU burst that is followed by
an I/O burst .
Internal Fragmentation: allocated memory may be slightly larger
than requested memory; this size difference is memory internal to a
partition, but not being used
Job queue: it have set of all processes in the system
Kernel threads : it can supported and managed directly by operating
system .
Long-term scheduler(or job scheduler) : selects which processes
should be brought into the ready queue
Logical address: commonly an address generated by the CPU
where an address seen by memory unit.
Lazy swapper: never swaps a page into memory unless page will be
needed , Swapper that deals with pages is a pager.
Multiprocessor system: parallel system or tightly coupled system.
Multiprogramming : increases CPU utilization by organizing jobs
(code and data) so that CPU always has one to execute
Message passing model : is a common model of interprocess
communication , which exchange message with one another to transfer
information.
Microkernel : is a method structures the operating system by removing
all nonessential components from the kernel and implementing them as
system and user level program and the result is smaller kernel.
Multi‐core programming : a recent trend in system design has been to
place multiple computing cores on a single chip , where each core appears
as a separate processor to the operating system
Medium term scheduler : some operating system , such as time –
sharing system , may introduce an additional , intermediate level of
scheduling.
Message passing : may be either blocking (synchronous ) or nonblocking (asynchronous ) .
Memory Management Unit: the run-time mapping from virtual to
physical address is done by a hardware device called MMU.
Modify bit ( dirty bit): A bit in a memory cache or virtual memory
page that has been modified by the CPU, but not yet written back to
.storage
Non‐preemptive ( cooperative) scheduling : CPU scheduling
decisions may take place when a process:
1.Switches from running to waiting state
2.Terminates
Operating System: A program that acts as an intermediary
between a user of a computer and the computer
hardware.
Program counter : is a processor register that indicates where the
computer is in its instruction sequence.
Protection and security :
Protection –any mechanism for controlling access of processes or users to
resources defined by the OS
Security –defense of the system against internal and external attacks
Process : is a program in execution.
Process Control Block (PCB) :it is contains many pieces of
Information associated with each process
Process mix : it is mixture of I/O bound and CPU bound process which
the long – term scheduler can select .
Preemptive scheduling: CPU scheduling decisions may take place
when a process:
1.Switches from running to ready state
2.Switches from waiting to ready
Process synchronization : Many systems provide hardware support
for critical section code
Physical address: its memory address that is electronically presented on
the computer address bus circuitry in order to enable the data bus to
access a particular storage cell of memory, also called real address.
Paging: is a memory-management scheme that permits the physical
address space of process to be noncontiguous.
Pages: breaking logical memory into blocks of the same size.
Page replacement: Page replacement completes separation between
logical memory and physical memory –large virtual memory can be
provided on a smaller physical memory.
Page fault: is an interrupt (or exception) to the software raised by the
hardware, when a program accesses a page that is mapped in address
space, but not loaded in physical memory
'Resource
allocator :is used to assign the available resources in an
economic way. It is part of resource management.
registry : a program which used to store and retrieve configuration
information.
Ready queue : it have a set of all processes residing in main
memory, ready and waiting to execute
Race condition : a situation where several processes access and
manipulate the same data concurrently and outcomes of the execution
depends on particular order in which the access the takes place
Relocation code: A code generated by an assembler or compiler, and in
which all memory references needing relocation are either specially
marked or relative to the current program-counter reading.
Relocation register: a hardware element that holds a constant to be
added to the address of each memory location in a computer program
running in a multiprogramming system, as determined by the location of
the area in memory assigned to the program.
System program :which are associated with the operating system but
are not part of the Kernel.
Symmetric multiprocessing : A multiprocessing architecture in which
multiple CPUs, residing in one cabinet, share the same memory. SMP
systems provide scalability
shells : the system with multiple command interpreters to choose from ,
the interpreters knows as shells
system call : provides an interface to the services made available by an
operating system , which is usually written in high level language such C,
C++.
shared memory model :a memory used to create and gain access to
region of memory owned by other processes .
Signal: it used in UNIX systems to notify a process that a particular
event has occurred
Stack : a process which contains a temporary data like ( function
parameters and local variables )
Short-term scheduler(or CPU scheduler) : is selects which
process should be executed next and allocates CPU
Swapping : a process which reintroduced into memory , and its
execution can be continued where it left off.
State save : of the current state of the CPU be it in the Kernel or
user mode , and then a state restore to resume operation
State restore : restore to resume operation .
Shared memory : interprocess communication using shared memory
requires communication process to establish a region of shared memory .
Short term scheduler : Selects from among the processes in memory
that are in ready queue to execute, and allocates the CPU to one of them
Swapping: a process can be swapped temporarily out of memory to a
backing store, and then brought back into memory for continued
execution.
Trap or exception : is a software-generated interrupt caused either by
an error or by a specific request from a user program that an operating
system service be performed.
Thread : a fundamental unit of CPU utilization that forms the basis of
multithreaded computer system .
Thread library : provides the programmer with an API for creating
and managing threads.
Thread cancellation : is the task of terminating a thread before it has
completed.
Translation look-side buffer (TLB): the standard solution to the
problem is to use a special, small, fast lookup hardware cache
User thread: it can support the threads and it could provided at the
user level , and it can support the kernel and managed without kernel
support.
User defined signal handler : the Default signal handler action can
overridden by User defined signal handler that is called to handle the
signal.
Unbounded buffer : places no practical limit on the size of the buffer.
Virtual memory: involves the separation of separation of user
.logical memory from physical memory
Virtual address space: is a memory mapping mechanism available in
modern operating systems such as OpenVMS, UNIX, Linux, and
Windows NT , and process refers to the logical or virtual view of how a
.process is stored in memory
Virus :a program to damage computer and data
Volatile storage: information residing in volatile storage does
not usually survive system
crashes
Waiting time : amount of time a process has been waiting in
the ready queue.
WAN wide-area network: usually links buildings , cities .
WIN32 threads: the technique for creating threads using the
Win32 thread library is
similar to the P threads technique in several ways.
Xcopy command : to make another copy of file in
a computer
Zero capacity: the queue has maximum length of zero
zip disk : it's a storage unit compressed to store the data
in magnetic field