Section 4: Synchronization And Data Transfer

Question 1

Define “producer” in the producer consumer model of data transfer

Answer 1

Either a software or hardware component responsible for producing data (or events) for the consumer

Question 2

Define “consumer” in the producer consumer model of data transfer

Answer 2

Either a software or hardware component responsible for consuming data (or using events) that have been produced by the producer.

Question 3

Name the two types of synchronization

Answer 3

1. Active

2. Passive

Question 4

Define active synchronization

Answer 4

One of the entities is capable of forcing a change in the operational characteristics of the other. Example: setting an interrupt signal can force the processor to execute the interrupt service routine.

Question 5

Define passive synchronization

Answer 5

One of the communicating entities signals a request for service, however the entity receiving the request is not forced to respond.

Question 6

Define spontaneous sources of data generation

Answer 6

Data is produced in the device independent of the actions of the consumer accepting the data

Question 7

Define “consumer sensitive sources” data generation

Answer 7

Data is produced by the device only after the previous data has been consumed by the consumer.

Question 8

Define “consumer responsive sources” data generation

Answer 8

Data is produced by the device only after requested by the consumer.

Question 9

Name the 3 types of data generation

Answer 9

1. Spontaneous
2. Consumer sensitive
3. Consumer responsive

Question 10

Define data transfer

Answer 10

Refers to all aspects of a transfer between two entities that have (potentially) different views of time.

Question 11

Define data persistence

Answer 11

How long data is valid for transfer between two communicating entities

Question 12

Define time synchronization and clocking

Answer 12

How signals, representing any data, are specified and enabled to make the transfer happen.

Question 13

Define control signalling

Answer 13

How any control information is exchanged between the communicating entities

Question 14

Define persistent dat

Answer 14

Information remains valid until consumer signals that the data has been collected (processed)

Question 15

Define transient data

Answer 15

Information is made available to the consumer and remains valid for a period of time and then may change. Minimum period of time is known by the designer.

Question 16

How does timing differ in synchronous and asynchronous data transfer?

Answer 16

Synchronous: Common view of time - sample every rising edge

Asynchronous: Different views of time - sample when time signal is received

Question 17

Explain the 3 steps necessary to perform and input/output transfer

Answer 17

1. Global initialization: Setting processor and I/O interface parameters necessary for the overall operation on the system
2. Transfer initialization: Setting processor and I/O interface to facilitate a specific process.
3. Transfer the data: including synchronization

Question 18

What are the 3 components of synchronized data transfer?

Answer 18

1. Data generation (spontaneous, consumer sensitive, consumer responsive)
2. Data notification / initiation of transfer (detect when data can be transferred)
3. Data transfer (actually perform the transfer)

Question 19

Define t_transfer-producer

Answer 19

The time for the device and interface combination to transfer one data unit

Question 20

Define t_transfer-consumer

Answer 20

The time the processor needs to transfer one data unit. May be longer or shorter than t_transfer-producer. Actual transfer time will be max(t_transfer-producer, t_transfer-consumer)

Question 21

Define t_synch

Answer 21

The execution time of the processor to synchronize with the availability of the data

Question 22

Define t_synch-poll

Answer 22

Polling synchronization uses processor time until just after the data is ready

Question 23

Define t_synch-inter

Answer 23

Interrupt synchronization only starts to use CPU time after the data has become available

Question 24

Define t_interdata

Answer 24

The time between consecutive data blocks.