Inside Macintosh: Devices /

Chapter 3 - SCSI Manager

This chapter describes the original Macintosh SCSI Manager. The SCSI Manager is the part of the Macintosh Operating System that controls the transfer of data between a Macintosh computer and peripheral devices connected through the Small Computer System Interface (SCSI).

In 1993, Apple Computer introduced SCSI Manager 4.3, an enhanced version of the SCSI Manager that provides new features as well as compatibility with the original version. SCSI Manager 4.3 is described in the chapter "SCSI Manager 4.3" in this book.

SCSI Manager 4.3 Note

Throughout this chapter, notes like this one are used to point out areas where SCSI Manager 4.3 differs from the original SCSI Manager.

You should read this chapter if you are writing a SCSI device driver or other program that needs to be compatible with the original SCSI Manager. To make best use of this chapter, you should understand the Device Manager and how device drivers are implemented in Macintosh computers. You should also be familiar with the SCSI-1 specification established by the American National Standards Institute (ANSI). The SCSI-1 specification appears in ANSI document X3.131-1986, entitled Small Computer System Interface. Unless otherwise noted, all mentions of a SCSI specification in this chapter refer to the SCSI-1 specification.

If you are designing a SCSI peripheral device for Macintosh computers, you should read Designing Cards and Drivers for the Macintosh Family, third edition, and Guide to the Macintosh Family Hardware, second edition.

This chapter provides a brief introduction to SCSI concepts and then explains

• how the SCSI standard is implemented on Macintosh computers
• how data is structured on SCSI disk drives and other block devices
• how you can use SCSI Manager routines and data structures to transfer data to and from SCSI peripheral devices

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Chapter Contents

Introduction to SCSI Concepts

SCSI Bus Signals

SCSI Bus Phases

SCSI Commands

SCSI Messages

SCSI Handshaking

About the SCSI Manager

Conformance With the SCSI Specification

Overview of SCSI Manager Data Structures

The Structure of Block Devices

The Driver Descriptor Record

The Partition Map

Using the SCSI Manager

Reading Data From a SCSI Device

Using CDB and TIB Structures

Using the SCSIComplete Function

Choosing Polled or Blind Transfers

SCSI Manager Reference

Data Structures

Driver Descriptor Record

Partition Map Entry Record

SCSI Manager TIB Instructions

SCSI Manager Routines

Summary of the SCSI Manager

Pascal Summary

Constants

Data Types

Routines

C Summary

Constants

Data Types

Functions

Assembly-Language Summary

Data Structures

Trap Macros

Result Codes