Archive PYTHON 4542 Manuals

Table of Contents

• • 4

    Table of Contents
  • 9

    Preface

• 10

  Chapter 1. Introduction

  • 10

    Overview
    • 10

      Data Compression
    • 13

      Figure 1-1 Python 4322 OAT Drive
    • 16

      Figure 1-4 SCSI System Sample Configurations
    • 19

      Flash EEPROM
  • 19

    Software
  • 20

    About This Manual
  • 20

    Table 1-2. Chapter Descriptions

• 22

  Chapter 2. Specifications

  • 22

    Overview
  • 22

    Physical Specifications
  • 24

    Figure 2-3 Python 4352 External Subsystem General Dimensions
  • 25

    Power Specifications
  • 26

    Table 2-3. Power Connector Pin Assignments (Models 4322 and 4542)
  • 26

    Table 2-4. Power Specifications for the Python 4352 Drives
  • 27

    Drive Performance Specifications
  • 28

    Environmental Requirements
  • 28

    OAT Cassette Specifications
  • 28

    Table 2-6. Environmental Specifications: Python DDS-DC Drives
  • 29

    Regulatory Compliance

• 30

  Chapter 3. Installation

  • 30

    Introduction
  • 30

    Guidelines and Cautions (4322 and 4542 Internal Models)
  • 31

    Unpacking and Inspection
  • 31

    Cabling and Connectors
    • 31

      Cabling Considerations
    • 31

      Electrical Characteristics
    • 32

      Single-Ended SCSI Connector
    • 33

      Table 3-1. Single-Ended SCSI Connector Pin Assignments: Models 4322 and 4542
  • 34

    Installing the Python 4322 and 4542 Internal Drives
    • 34

      Table 3-2. Single-Ended SCSI Connector Pin Assignments: Model 4352
    • 35

      Figure 3-1 Python 4322 Switchbank Access
    • 35

      Setting Operational Switches
    • 38

      Figure 3-4. SCSI Device Address Selection (4322 and 4542)
    • 41

      Figure 3-5 JP6 External SCSI Address Port
    • 41

      Mounting the Drive Unit
    • 42

      Figure 3-6. Mounting Hole Locations (4322)
    • 43

      Figure 3-7. Mounting Hole Locations (4542)
    • 44

      Completing Connections
    • 44

      Figure 3-8. Power and SCSI Connectors
  • 45

    Installing the Python 4352 External Drive
    • 45

      Figure 3-9. Power and SCSI Connectors
    • 46

      Completing the Interface Connection
    • 46

      Figure 3-10 Python 4352 Rear Panel
    • 46

      Selecting the SCSI Address
    • 47

      Connecting the Power Cord
    • 47

      Figure 3-11 Daisy Chain Diagram

• 48

  Chapter 4. Drive Operation

  • 48

    Introduction
  • 48

    Data Compression Operation
  • 49

    Front Panel LED Operation
  • 50

    Figure 4-1. Python 4322 Front Panel
  • 50

    Figure 4-2. Python 4542 Front Panel
  • 51

    Figure 4-3. Python 4352 Front Panel
  • 51

    Table 4-1. LED Summary
  • 52

    Loading/Unloading the Cassette
    • 52

      Loadinglunloading a Cassette (Normal Operation)
    • 52

      Figure 4-4 Cassette Loading (4322 OAT Drive)
    • 53

      Unloading a Cassette (Manual Operation)
    • 54

      Figure 4-5. Manually Removing a Cassette
    • 55

      Figure 4-6. Manually Removing a Cassette
  • 56

    Using a Blank Cassette
  • 56

    Figure 4-7. Manually Removing a Cassette
  • 57

    Using a Cassette Containing Data
  • 57

    Using a Prerecorded Audio Cassette
  • 58

    Loading Revised Firmware Via Archive Firmware Cassette
  • 60

    Chapter S. SCSI Interface
    • 60

      Introduction
    • 60

      SCSI-1 Interface
    • 63

      ANSI X3.131 Conformance Statement (SCSI-I)
    • 64

      SCSI-2 Interface
    • 66

      ANSI X3T9.2 Conformance Statement (SCSI-2) (Working Draft, Rev 10)

• 68

  Chapter 6. Tape Formats

  • 68

    Introduction
    • 68

      DDS Format
    • 69

      DDS-DC Format
    • 69

      Commonalities Between the Formats
  • 70

    Entities (DDS-DC Format Only)
  • 71

    Tape Layout
  • 71

    Single Data Space Layout
    • 72

      Device Area
    • 72

      Reference and System Area
    • 72

      Figure 6-1 Single Data Space Tape Layout
    • 73

      Figure 6-2 Reference and System Area Layout
    • 74

      Data Area
    • 74

      End-Of-Data (EOD) Area
  • 74

    Two-Partition Layout
  • 75

    Data Storage Organization
  • 75

    Figure 6-3 Two-Partition Tape Layout
  • 76

    Individual Track Layout
    • 76

      Main Area
    • 76

      Figure 6-4 Individual Track Layout
    • 77

      Subareas
  • 78

    Group Structure
    • 78

      Figure 6-5 Group Structure
    • 79

      Data Frames
    • 79

      ECC Frame
    • 79

      Index
    • 80

      Amble Frames
  • 80

    Indexing
    • 80

      Group Information Table (GIT)
    • 81

      Block Access Table (BAT)
  • 82

    Vendor Group
  • 83

    Read-After,Write

• 84

  Chapter 7. Data Compression

  • 84

    Introduction
    • 84

      Data Compression Considerations
    • 85

      DCLZ Algorithm
    • 86

      Hardware Compression
    • 86

      Data Integrity
  • 86

    DCLZ Algorithm
    • 87

      Simplified Compression Operation
    • 87

      Table 7-1. Simplified Compression
    • 88

      Dictionary
    • 89

      Simplified Decompression Operation
    • 89

      Table 7-2. Simplified Decompression
  • 90

    AHA3101 Data Compression Chip

• 92

  Chapter 8. Theory of Operation

  • 93

    Block Diagrams
  • 93

    Python DDS-DC DAT Drives
    • 95

      Figure 8-2 Block Diagram -- SCSI Controller Python Models 4322NT and 4542NT DDS-DC Drives
    • 96

      Figure 8-3 Block Diagram -- SCSI Controller Python Models 4322NP, 4542NP, and 4352XP DDS-DC Drives
    • 97

      Figure 8-4 Python State Diagram
    • 98

      Figure 8-5 Four-Head Design
    • 98

      Helical Scan Recording -- Four-Head Design
    • 99

      Figure 8-6 Alternate Azimuth Angles
    • 99

      Motors and Control Circuits
    • 101

      Audio Output Jack
    • 101

      Flash EEPROM
    • 101

      Sensors
    • 102

      Figure 8-7 OAT Cassette
    • 103

      Figure 8-8. Cassette Design Features
    • 104

      Table 8-1. Tape Lengths and Capacities

• 106

  Chapter 9. Maintenance and Reliability

  • 106

    Maintenance
    • 106

      Head Cleaning
    • 107

      Automatic Drive Spin-Down and Write
    • 107

      Guidelines for High Temperature or Humidity Conditions
  • 108

    Reliability
    • 108

      Mean-Time-Between-Failure
    • 108

      Mean-Time-To-Repair
    • 108

      Table 9-1. Reliability Specifications

• 110

  Appendix Aglossary of Terms

• 114

  Appendix A. Glossary of Terms . . .

• 114

  Appendix B. Acronyms and Measurements

  • 116

    Measurements

• 118

  Appendix C. Data Compression---Scsi Information. . . . . .

  • 118

    Introduction
  • 118

    MODE SELECT Page
  • 118

    Table C-1. Data Compression MODE SELECT Page
    • 119

      Compression Control
    • 119

      Decompression Control
  • 120

    Table C-2. DDE and RED Bit Configurations
    • 121

      MODE SENSE Page
  • 121

    Table C-3. Algorithms
  • 121

    Table C-4. Data Compression MODE SENSE Page
    • 122

      Compression Control
    • 122

      Decompression Control
    • 123

      Compression Algorithm
    • 123

      Decompression Algorithm
    • 123

      Request Sense Data
    • 124

      Implementation Notes
  • 124

    Table C-6. Sense Data Values and Descriptions
    • 125

      C.S.2 SCSI Command Operation for Noncompressing Modes
    • 127

      WRITE DATA BUFFER (3Bh)
      • 127

        C.6.L WRITE DATA BUFFER Command Descriptor Block
  • 127

    Table C-7. Command Descriptor Block: WRITE DATA BUFFER
    • 128

      Command Descriptor Block Field Descriptions
    • 128

      WRITE DATA BUFFER Data Header
  • 128

    Table C-8. Field Descriptions: WRITE DATA BUFFER Command Descriptor Block
    • 129

      Completion Status

• 118

  Appendix Cdata Compression