SCSI Glossary

SCSI FAQ Part 3

• Q. 54. I need a terminator for my SCSI bus consisting of a number of HVD disk drives. I do not need a pass-through HVD terminator, but that is all I can find. Can I use it for the terminator at the end of this HVD bus?
• Q. 55. How can I tell if an unmarked terminator is SE or differential?
• Q. 56. I have a SCSI peripheral but I do not know if it has the single-ended, HVD or LVD interface. Is there an easy way to tell?
• Q. 57. How can I tell if a single-ended terminator is active or passive?
• Q. 58. What kind of terminators does LVD SCSI require?
• Q. 59. I have heard about "high byte termination". What is it?
• Q. 60. What is "active negation"?
• Q. 61. How far apart should I space peripherals on the bus?

• Q. 62. On an internal (ribbon) SCSI cable, into which connectors do I plug my peripherals?
• Q. 63. If I have an internal SCSI ribbon cable with connectors for "x" devices, do they all need to be filled?
• Q. 64. What are the cable length limits for single-ended SCSI?
• Q. 65. What are the cable length limits for differential (HVD) SCSI?
• Q. 66. What are the cable length limits for LVD SCSI?
• Q. 67. What is the maximum data throughput for SCSI-1?
• Q. 68. What is the maximum data throughput and cable length for SCSI-2 (Fast)?
• Q. 69. What is the maximum data throughput for Ultra SCSI (Fast-20)?
• Q. 70. What is the maximum data throughput for LVD (Ultra 2 or Fast-40) SCSI?

• Q. 71. What is the maximum data throughput for Ultra160 (Ultra 3 or Fast-80) LVD SCSI?
• Q. 72. What is SCSI-3?
• Q. 73. What is a SCSI-1 connector?
• Q. 74. What is a SCSI-2 connector?
• Q. 75. What is a SCSI-3 connector?
• Q. 76. What is a SCSI-4 or SCSI-5 connector?
• Q. 77. What is the VHDCI connector?
• Q. 78. What is a SCA connector?

• Q. 79. Where can I find SCSI connector pinout information?
• Q. 80. Where can I find drawings or photos to help me identify the various SCSI connectors?
• Q. 81. What is a SCSI expander?
• Q. 82. Where can I find books on SCSI?
• Q. 83. Where can I get official ANSI SCSI documentation?
• Q. 84. Where can I get documents on emerging SCSI specs?
• Q. 85. Can I locate peripherals more than 25 meters from the host?
• Q. 86. Is there anything I can do if I need to locate a peripheral more than the SCSI recommended cable length from the host?

• Q. 87. How can I locate SCSI backup devices in another building or another part of this building?
• Q. 88. What effect does SCSI cable impedance mismatches have and what are the symptoms?
• Q. 89. What causes impedance mismatches in SCSI subsystems and what can I do to reduce them?
• Q. 90. I have read that I should not try to save money when purchasing SCSI cables? Why?
• Q. 91. Must I use twisted pairs in my ribbon cables or round SCSI cabling?
• Q. 92. What are the rules for SCSI terminators? What kind of terminators should I use and where should I put them?
• Q. 93. I had some problems with a SCSI system that I seemed to cure by placing a third terminator on the bus. This violates SCSI terminator rules. Why did it seem to work?

• Q. 94. How do I assign SCSI IDs to various devices on the bus?
• Q. 95. What is the priority sequence of SCSI IDs?
• Q. 96. In what order do SCSI IDs have to be assigned?
• Q. 97. What is a SCSI "domain"?
• Q. 98. What is a SCSI bus "segment"?
• Q. 99. What is a "device"?
• Q. 100. What is a "stub"?
• Q. 101. What is "SCAM"?
• Q. 102. Does it hurt to have more than one device supplying term power?
• Q. 103. I have a hard disk connected to the PCMCIA host adapter card in my laptop but it does not work. What is wrong?
• Q. 104. Next to the connector on some SCSI devices I have noticed various diamond-shaped symbols. What do they mean?

Part 1 Q. | Part 1 A. | Part 2 Q.| Part 2 A.  Part 3 Q. | Part 3 A. | Part 4 Q.| Part 4 A.