Data Processing

Polling vs. Interrupts

PollingSimilar to voting (hence “polling”)Cycle through all clients to see if they have

requestsInterrupts

Similar to students raising handsClients interrupt server and make a request

Real-time vs. Batch Processing

Real-time processingNo waitingHandle things in “real-time” as they happenExample: Air traffic control

Batch processingWait for a period of time for events to queue

upHandle all the events in one batchExample: Updating all computers overnight

Variations and Combinations

Polling & Real-time processingPolling & Batch-processingInterrupts & Real-time processingInterrupts & Batch-processing

Assignment Grading Example

Polling with Real-time processing1. Teacher asks each student if they are done2. Teacher grades student’s assignment immediately after

he/she turns it in

Polling with Batch-processing1. Teacher asks each student if they are done2. Teacher grades all submitted assignments in one sitting

Interrupts with Real-time processing1. Student turns in assignment to teacher whenever2. Teacher grades assignment immediately

Interrupts with Batch-processing1. Student turns in assignment to teacher whenever2. Teacher grades all submitted assignments in one sitting

Identify the proper system design for the following scenarios

Example: Homework – polling with batch processing

• Air traffic control• Printer system with multiple clients• Processing checks at a bank• Printing report cards for students• Library books being returned• Telephone call routing (e.g. main office)• Voting for SCA officers• College application reviews