Prelim Flashcards
can be treated as a unit of activity that executes a sequence of instructions, a current state, and an associated set of system resources.
process
the two (2) essential elements of a process, one of which can be shared with other processes that are executing the same program
program code
the two (2) essential elements of a process, one of which is associated with the program code
set of data
It is a unique identifier for each process.
Identifier
It indicates the current activity of a process
Process State
Priority
It refers to the level relative to other processes
It indicates the address of the next instruction to be
executed for a particular process.
Program counter
It contains pointers to program codes and data
associated with the process, including any memory blocks shared with
other processes.
Memory pointer
These are the data present in a processor’s registers
during process execution
Context data
This includes different information associated
with the input/output status of a process, such as the outstanding I/O
requests and I/O devices assigned to the process
I/O status information
This includes different tracking information
associated with the process, such as the amount of processor time, the
clock time used, and time limits.
Accounting information
An operating system controls the course of execution that involves the process
of determining an interleaving pattern for execution and allocating resources
to processes.
Two-State Process Model
When the OS creates a new process, it creates a
process control block for the new process and adds the new process into
the not running state of the system.
Not running state
This model naturally handles processes through the implementation of five
unique states
Five-State Process Model
A process that has just been created and has not yet been
admitted to the pool of executable processes by the OS
New state
The process that is currently being executed
Ready state
: A process that cannot execute until some
event occurs, such as the completion of an I/O operation
Blocked state/Waiting state
A process that has been released from the pool of executable
processes by the OS, either because it halted or it was terminated.
Exit state
In a this model, processes that are not immediately available
for execution can occur. These processes may or may not be waiting for a
specific event.
Suspended Processes
– These are used to keep track of both the main and
the secondary memory
Memory tables
These are used by the OS to manage the input and output
devices and channels of a computer system at any given point in time.
I/O tables
These tables hold information regarding the existence of
files and its corresponding attributes through a file management
system.
File tables
These tables are maintained by the OS to manage
processes.
Process tables
At a minimum, a process must include a program to be
executed. Associated to this program is a set of data locations for local and
global variables and any defined constants.
Process Location
