OS Distributed Communication

write & delete message

delete & receive message

send & delete message

receive & send message

Programmed buffering

Automatic buffering

User defined buffering

No buffering

the CPU uses polling to watch the control bit constantly, looping to see if a device is ready

the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available

the CPU receives an interrupt when the device is ready for the next byte

the CPU runs a user written code and does accordingly

Sending signals to CPU through bus

Executing a special operation called system call

Executing a special program called system program

Executing a special program called interrupt trigger program

have to be of a fixed size

have to be a variable size

can be fixed or variable sized

None of the mentioned

wait

fork

exit

exec

Normally

Abnormally

Normally or abnormally

None of the mentioned

a condition variable must be declared as condition

condition variables must be used as boolean objects

semaphore must be used

all of the mentioned

is referred to as a message system with buffering

is referred to as a message system with no buffering

is referred to as a link

none of the mentioned

dynamic condition

race condition

essential condition

critical condition