3. PROCESS CONTROL BLOCK
Each & every process in the operating
system is represented by PROCESS CONTROL
BLOCK.
Process Control Block also known as
Task Controlling Block or Process Table.
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4. PROCESS CONTROL BLOCK
Its is a data structure in the operating
system kernel containing the information
needed to manage a particular process.
The PCB is “ the manifestation(visible) of
a process in an operating system”
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6. PROCESS CONTROL BLOCK (PCB)
PCB consist of following information~
Pointer .
Process state .
Program counter .
CPU register .
CPU scheduling information .
Memory management information .
Accounting information .
I/O status information . 6
7. PROCESS CONTROL BLOCK (PCB)
POINTER ~ Its contains the address of another
process which is present in the ready queue
PROCESS STATE ~ Its contains the information
about the state of the process i.e.,
NEW
READY
RUNNING
WAITING
HALTED
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8. PROCESS CONTROL BLOCK (PCB)
program COUNTER - The counter specifies the
address of the next instruction to be executed.
CPU REGISTERS - The register vary in number and
type depending in the type of computer
architecture, they include:
Accumulators, index register, stack pointer and
general purpose registers 8
9. PROCESS CONTROL BLOCK (PCB)
CPU SHEDULING INFORMATION –
This information includes
Process priority
Pointer to scheduling queues
Other scheduling parameters.
MEMORY MANAGEMENT INFORMATION –
This information includes
Value of base and limit of registers
Page tables
Segment tables
Depending on the memory system used by the
operating system.
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10. PROCESS CONTROL BLOCK (PCB)
ACCOUNTING INFORMATION – This information includes
amount of CPU and real time used
time limit
account number
job or process number etc.
I/O STATUS INFORMATION - This information includes
list of I/O devices allocated to the process
list of open files etc.
Hence, the PCB serves as the repository for any
information that may be vary from process to process.
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