2.6 operating systems

Question 1

role of the kernel (process management)

Answer 1

process management - process execution, including the allocation of the processor time and termination is controlled by the kernel so the system makes efficient use of the CPU and functions properly

Question 2

role of kernel (memory management)

Answer 2

memory management- the kernel keeps track of the sections of memory that are currently allocated, manages the release of memory once processes have been executed and allocates/re-allocated memory to new processes that are ready for execution

Question 3

role of kernel (device management/ I/O communication)

Answer 3

manages all the systems devices via communication with device driver software. all user inputs and all process outputs are handled by the kernel

Question 4

role of kernel (interrupt handling)

Answer 4

higher priority processes that are ready for execution will generate an interrupt signal, or request for the CPU access. The kernel will handle the interruption of current processing, enable the CPU to process the higher priority even and then manage the return to the interrupted process

Question 6

modes of operation (batch processing)

Answer 6

-process is carried out with no user interaction
-may avoid using computer resources at times when demand is high
-errors are stored in a file for later use and not dealt with as they occur
-completes repetitive tasks

examples - updating a master file - payroll

input method - scanning of OCR sheets, batch file

output method - printing of pay slip

Question 7

modes of operation (real time systems)

Answer 7

• continuous applications that have no end
• deal with events that occur simultaneously and unpredictably
• some are safety critical
• response to an even with a specified amount of time

examples - missile guidance

Question 8

modes of operation (real time control systems)

Answer 8

-immediate reaction
-inputs are processed quickly, processing needs to be fast enough to deliver outputs in time and adjust outputs accordingly to avoid accidents

example - theatre seat booking

Question 9

modes of operation (transaction processing)

Answer 9

-accessing and updating tables in a database as part of a transaction file that needs to be dealt with immediately

example - supermarket system