Chapter 10 - Message passing. This chapter discusses the semantics of message passing, and OS responsibilities in buffering and delivery of interprocess messages. It also discusses how message passing is employed in higher-level protocols for providing electronic mail facility and in providing intertask communication in parallel or distributed programs. | PROPRIETARY MATERIAL. © 2007 The McGraw-Hill Companies, Inc. All rights reserved. No part of this PowerPoint slide may be displayed, reproduced or distributed in any form or by any means, without the prior written permission of the publisher, or used beyond the limited distribution to teachers and educators permitted by McGraw-Hill for their individual course preparation. If you are a student using this PowerPoint slide, you are using it without permission. Message passing preliminaries The sender process names the destination process and provides the message The destination process specifies an area in which the message should be put Issues in message passing Naming of processes Direct and indirect naming Direct: Process names are specified in send / receive commands Indirect: Process names are inferred by the kernel Symmetric and asymmetric naming Symmetric: Both sender and receiver processes specify each other’s names Asymmetric: Receiving process does not specify name of a sender | PROPRIETARY MATERIAL. © 2007 The McGraw-Hill Companies, Inc. All rights reserved. No part of this PowerPoint slide may be displayed, reproduced or distributed in any form or by any means, without the prior written permission of the publisher, or used beyond the limited distribution to teachers and educators permitted by McGraw-Hill for their individual course preparation. If you are a student using this PowerPoint slide, you are using it without permission. Message passing preliminaries The sender process names the destination process and provides the message The destination process specifies an area in which the message should be put Issues in message passing Naming of processes Direct and indirect naming Direct: Process names are specified in send / receive commands Indirect: Process names are inferred by the kernel Symmetric and asymmetric naming Symmetric: Both sender and receiver processes specify each other’s names Asymmetric: Receiving process does not specify name of a sender process Issues in message passing Method for transferring messages Process executing a receive command is blocked until a message is delivered The sender process may or may not be blocked until delivery Synchronous message passing: sender is blocked Simplifies message passing, saves memory Asynchronous message passing: sender is not blocked Order in which messages are delivered Handling of exceptions like non-existing processes, undeliverable messages Issues in message passing Kernel responsibilities Buffering of messages Kernel builds an interprocess message control block (IMCB) IMCB is stored in an appropriate data structure The message may be stored in IMCB or separately Blocking and unblocking of processes May be performed using event control blocks (ECBs) Interprocess message control block (IMCB) Lists of IMCBs pending delivery of messages Symmetric naming and blocking sends A process executes send and destination process has not executed receive A process executes receive and .
