Inside Macintosh: Devices /

Chapter 4 - SCSI Manager 4.3

SCSI Manager 4.3 is an enhanced version of the SCSI Manager that provides new features as well as compatibility with the original version. SCSI Manager 4.3 is contained in the ROM of high-performance computers such as the Macintosh Quadra 840AV and the Power Macintosh 8100/80. Beginning with system software version 7.5, SCSI Manager 4.3 is also available as a system extension that can be installed in any Macintosh computer that uses the NCR 53C96 SCSI controller chip.

In addition to the capabilities of the original SCSI Manager, SCSI Manager 4.3 provides

• support for asynchronous SCSI I/O
• support for optional SCSI features such as disconnect/reconnect
• a hardware-independent programming interface that minimizes the SCSI-specific tasks a device driver must perform

You should read this chapter if you are writing a SCSI device driver or other software for Macintosh computers that use SCSI Manager 4.3. To make best use of this chapter, you should understand the Device Manager and the implementation of device drivers in Macintosh computers. If you are designing a SCSI peripheral device for the Macintosh, you should read Designing Cards and Drivers for the Macintosh Family, third edition, and Guide to the Macintosh Family Hardware, second edition.

This chapter assumes you are familiar with the following SCSI specifications established by the American National Standards Institute (ANSI):

• X3.131-1986, Small Computer System Interface
• X3.131-1994, Small Computer System Interface-2
• X3.232 (draft), SCSI-2 Common Access Method

If you are writing a device driver for a block-structured storage device such as hard disk, you should also read the chapter "SCSI Manager" in this book for information about the structure of block devices used by the Macintosh Operating System. Because many Macintosh models continue to use the original SCSI Manager, you may want to design your software to operate with both SCSI Manager 4.3 and the original SCSI Manager.

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Chapter Contents

About SCSI Manager 4.3

Transport

SCSI Interface Modules

System Performance

Compatibility

Using SCSI Manager 4.3

Locating SCSI Devices

Describing Data Buffers

Handshaking Instructions

Error Recovery Techniques

Optional Features

Writing a SCSI Device Driver

Loading and Initializing a Driver

Selecting a Startup Device

Transitions Between SCSI Environments

Handling Asynchronous Requests

Handling Immediate Requests

Virtual Memory Compatibility

Writing a SCSI Interface Module

SIM Initialization and Operation

Supporting the Original SCSI Manager

Handshaking of Blind Transfers

Supporting DMA

Loading Drivers

SCSI Manager 4.3 Reference

Data Structures

Simple Data Types

Device Identification Record

Command Descriptor Block Record

Scatter/Gather List Element

SCSI Manager Parameter Block Header

SCSI I/O Parameter Block

SCSI Bus Inquiry Parameter Block

SCSI Abort Command Parameter Block

SCSI Terminate I/O Parameter Block

SCSI Virtual ID Information Parameter Block

SCSI Load Driver Parameter Block

SCSI Driver Identification Parameter Block

SIM Initialization Record

SCSI Manager 4.3 Functions

Client Functions

SIM Support Functions

SIM Internal Functions

Summary of SCSI Manager 4.3

C Summary

Constants

Data Types

Functions

Pascal Summary

Constants

Data Types

Routines

Assembly-Language Summary

Data Structures

Trap Macros

Result Codes