Viper 60s Theory Of Operation And Maintenance Manual page 10

VIPER SCSI 60, 125 & 150 THEORY OF OPERATION AND MAINTENANCE
5.24 PREVENT / ALLOW Media Removal (1Eh) ..... , .......... , .... , .......................................... 5-67
5.24.1 PREVENT/ALLOW MEDIA REMOVAL Command Descriptor Block ....... 5-67
5.24.2 Command Descriptor Block Field Description ................................................. 5-67
5.24.3 Completion Status .................................................................................................. 5-68
5.25 WRITE DATA BUFFER (3Bh) ........................................................................................ 5-69
5.25.1 WRITE DATA BUFFER Command Descriptor Block ...................................... 5-69
5.25.2 Command Descriptor Block Field ....................................................................... 5-70
5.25.3 WRITE DATA BUFFER Data Header ................................................................. 5-70
5.25.4 Completion Status .................................................................................................. 5-71
5.26 READ DATA BUFFER (3Ch) ......................................................................................... 5-72
5.26.1 READ DATA BUFFER Command Descriptor Block ........................................ 5-72
5.26.2 Command Descriptor Block Field ....................................................................... 5-72
5.26.3 READ DATA BUFFER Header ............................................................................ 5-73
5.26.4 READ DATA BUFFER Header Field .................................................................. 5-73
5.26.5 Completion Status .................................................................................................. 5-73
Chapter
6
Theory of Operations .............................................................................................................. 6-1
6.1 Overview .............................................................................................................................. 6-1
6.2 Printed Circuit Board ......................................................................................................... 6-1
6.2.1 Basic VLSI Controller ................................................................................................ 6-3
6.2.2 Write and Erase Circuits .......................................................................................... 6-5
6.2.3 Read Circuits .............................................................................................................. 6-6
6.2.4 Tape Hole Sensor ....................................................................................................... 6-7
6.2.5 Phase Lock Loop ........................................................................................................ 6-7
6.2.6 Reset Circuits ............................................................................................................. 6-7
6.3 Data Transfer ....................................................................................................................... 6-8
6.3.1 Erase Operation ......................................................................................................... 6-8
6.3.2 Write Data (Backup) Operation .............................................................................. 6-9
6.3.3 Read Data (Restore) Operation .............................................................................. 6-10
6.4 Drive Mechanics ................................................................................................................ 6-10
6.4.1 Loading Mechanism ................................................................................................ 6-10
6.4.2 Cartridge Loading .................................................................................................... 6-10
6.4.3 Cartridge Removal ................................................................................................... 6-11
6.4.4 Tape Motion .............................................................................................................. 6-11
6.5 Sensors/Interlocks ............................................................................................................. 6-11
6.5.1 Cartridge Switch Assembly .................................................................................... 6-11
6.5.2 Write Protect ............................................................................................................. 6-12
6.5.3 Tape Hole Sensors .................................................................................................... 6-12
6.6 Motor Driver Printed Circuit Board ............................................................................... 6-12
6.6.1 Interface ..................................................................................................................... 6-13
6.6.2 Motor Controller LSI ................................................................................................ 6-14
6.6.3 EPROM Interface ...................................................................................................... 6-16
6.7 Head Assembly .................................................................................................................. 6-16
6.7.1 Read/Write Head Operation ................................................................................. 6-16
6.7.2 Serpentine Recording .............................................................................................. 6-18
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