Section 4: Synchronization And Data Transfer Flashcards
Define “producer” in the producer consumer model of data transfer
Either a software or hardware component responsible for producing data (or events) for the consumer
Define “consumer” in the producer consumer model of data transfer
Either a software or hardware component responsible for consuming data (or using events) that have been produced by the producer.
Name the two types of synchronization
- Active
2. Passive
Define active synchronization
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.
Define passive synchronization
One of the communicating entities signals a request for service, however the entity receiving the request is not forced to respond.
Define spontaneous sources of data generation
Data is produced in the device independent of the actions of the consumer accepting the data
Define “consumer sensitive sources” data generation
Data is produced by the device only after the previous data has been consumed by the consumer.
Define “consumer responsive sources” data generation
Data is produced by the device only after requested by the consumer.
Name the 3 types of data generation
- Spontaneous
- Consumer sensitive
- Consumer responsive
Define data transfer
Refers to all aspects of a transfer between two entities that have (potentially) different views of time.
Define data persistence
How long data is valid for transfer between two communicating entities
Define time synchronization and clocking
How signals, representing any data, are specified and enabled to make the transfer happen.
Define control signalling
How any control information is exchanged between the communicating entities
Define persistent dat
Information remains valid until consumer signals that the data has been collected (processed)
Define transient data
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.
How does timing differ in synchronous and asynchronous data transfer?
Synchronous: Common view of time - sample every rising edge
Asynchronous: Different views of time - sample when time signal is received
Explain the 3 steps necessary to perform and input/output transfer
- Global initialization: Setting processor and I/O interface parameters necessary for the overall operation on the system
- Transfer initialization: Setting processor and I/O interface to facilitate a specific process.
- Transfer the data: including synchronization
What are the 3 components of synchronized data transfer?
- Data generation (spontaneous, consumer sensitive, consumer responsive)
- Data notification / initiation of transfer (detect when data can be transferred)
- Data transfer (actually perform the transfer)
Define t_transfer-producer
The time for the device and interface combination to transfer one data unit
Define t_transfer-consumer
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)
Define t_synch
The execution time of the processor to synchronize with the availability of the data
Define t_synch-poll
Polling synchronization uses processor time until just after the data is ready
Define t_synch-inter
Interrupt synchronization only starts to use CPU time after the data has become available
Define t_interdata
The time between consecutive data blocks.
