CS452 - Real-Time Programming - Fall 2009

Lecture 9 - Send/Receive/Reply

Reminder

Send/Receive/Reply

Message-Passing Primitives

Send

Receive

Reply

Producer/Consumer

Two ways to do this

1. Producer Sends, consumer Receives
   • Send means "Here is some data"
   • Receive means "I'm ready to receive data"
   • Reply means "I got the data"

   After Reply buffers holding data can be overwritten at will

2. Producer Receives and Replys
   • Send means "I'm ready for data"
   • Receive means "I'm ready to transmit data"
   • Reply means "Here's the data"

   After Reply buffers can be overwritten at will.

What is the difference?

1. If relationship is one-to-one
   • no difference
2. If relationship is many-to-one
   • the one doing many MUST Receive.

If relationship is many-to-many

• there must be an extra component that Receives from both

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