User manual TANDBERG SLR AUTOLOADER PROGRAMMER

TANDBERG SLR AUTOLOADER SCSI INTERFACE FUNCTIONAL SPECIFICATIONS TM TANDBERG DATA ASA P.O. Box 134 Kjelsås N-0411 OSLO, NORWAY Phone + 47 22 18 90 90 Telefax + 47 22 18 95 50 © Tandberg Data ASA Part No. 43 20 73-03 December 2003 Related publications available from our Marketing Department: Part No. 43 21 77 - 03 43 20 72 - 03 43 20 74 - 01 43 04 44 - 11 43 07 43 - 13 Title Tandberg SLR Autoloader Installation and User Manual Tandberg SLR Autoloader Service and Repair Manual Tandberg SLR Autoloader Product Verification Reports Tandberg SLR7 ­ SLR140 Reference Manual Tandberg SLR7 ­ SLR140 SCSI Interface Functional Specification This publication may describe designs for which patents are granted or pending. By publishing this information, Tandberg Data ASA conveys no license under any patent or any other rights. Every effort has been made to avoid errors in text and diagrams. However, Tandberg Data ASA assumes no responsibility for any errors which may appear in this publication. It is the policy of Tandberg Data ASA to improve products as new techniques and components become available. Tandberg Data ASA therefore reserves the right to change specifications at any time. We would appreciate any comments on this publication. Table of Contents 1 2 2.1 2.2 2.3 2.3.1 2.3.2 2.3.3 2.4 2.4.1 2.4.2 2.4.3 2.4.4 2.4.5 2.5 2.5.1 2.5.2 2.5.3 2.5.4 2.6 2.6.1 2.6.2 2.6.3 2.6.4 2.6.5 2.6.6 2.6.7 2.6.8 2.7 2.8 2.9 2.10 2.10.1 2.10.2 2.10.3 2.10.4 2.10.5 2.11 2.12 2.12.1 2.13 2.13.1 2.14 2.14.1 2.15 2.16 2.16.1 2.17 2.18 3 3.1 3.2 Overview SCSI Commands INITIALIZE ELEMENT STATUS 07h INITIALIZE ELEMENT STATUS WITH RANGE E7h INQUIRY 12h Standard Inquiry Response Supported Vital Product Data Page 00h Unit Serial Number Page 80h LOG SENSE 4Dh LOG SENSE Page Format LOG SENSE Page Header Format LOG SENSE Page 00h Format LOG SENSE Page 2Eh Format LOG SENSE Page 30h, 31h, 32h Format MODE SELECT 15h MODE SELECT Parameter List MODE SELECT Page Format Element Address Assignment Page 1Dh Library Mode Page 23h MODE SENSE 1Ah MODE SENSE Parameter List MODE SENSE Page Format Element Address Assignment Page 1Dh Default, Changeable and Saved Values for Page 1Dh Transport Geometry Parameters Page 1Eh Device Capabilities Page 1Fh Library Mode Page 23h Library Configuration Page 24h MOVE MEDIUM A5h POSITION TO ELEMENT 2Bh PREVENT ALLOW MEDIUM REMOVAL 1Eh READ ELEMENT STATUS B8h Element Status Data Header Medium Transport Element Status Page Storage Element Status Page Import Export Element Status Page Data Transfer Element Status Page RELEASE 17h REQUEST SENSE 03h Sense Information Format REQUEST VOLUME ELEMENT ADDRESS B5h Volume Element Address Header RESERVE 16h Element List Descriptor SEND DIAGNOSTIC 1Dh SEND VOLUME TAG B6h Send Volume Tag Parameter List TEST UNIT READY 00h WRITE BUFFER 3Bh SCSI Status and Messages Supported SCSI Status Codes Supported SCSI Message Codes 1-1 2-1 2-2 2-3 2-4 2-5 2-8 2-8 2-9 2-10 2-10 2-11 2-11 2-13 2-14 2-14 2-15 2-16 2-17 2-18 2-19 2-19 2-20 2-21 2-22 2-23 2-25 2-26 2-27 2-28 2-28 2-29 2-30 2-31 2-33 2-35 2-37 2-39 2-40 2-41 2-45 2-46 2-47 2-48 2-49 2-50 2-51 2-52 2-53 3-1 3-1 3-1 This Page Intentionally Left Blank ______________________________________________________________________ 1 Overview The purpose of this specification is to provide a definition of the SCSI implementation for the Tandberg Data SLR Loader medium changer device. For SCSI implementation information regarding the SLR tape drives (Data transfer element), refer to the SLR7-140 Programers Manual: SCSI-2 Interface Functional Specifications Tandberg Data P/N 430743. The SLR Loader consists of one medium changer device, one SLR tape drive, one eight-cartridge removable magazine, and an integrated bar code reader. The medium changer and the tape drive are single LUN SCSI devices, each occupying a unique SCSI address. The individual SCSI address of the autoloader and the internal drive are programble from the front pannel of the unit. The SLR Autoloader supports both Single-ended and LVDS SCSI interfaces as standard. The dual SCSI connectors on the back of the unit are the standard SCSI-3 68-pin high-density connectors. Refer to the SLR Autoloader Installation Manual (Tandberg Data P/N 432177 (SLR60-140)) for details on SCSI addressing, interconnect, termination, and cabling considerations. All SLR Loader configurations utilize three of the medium changer element types defined in the SCSI Standard - one data transfer element (the tape drive), one medium transport element (the cartridge picker/elevator), and the storage elements (one for each magazine slot). The SLR Loader operates in either sequential or random access mode, depending on the configuration stored in its non-volatile memory. In random access mode, cartridges are moved to and from the tape drive by issuing the SCSI MOVE MEDIUM command to the medium changer device. In sequential mode, cartridges are sequentially moved by issuing the SCSI UNLOAD command to the tape drive (after manually loading the first tape). Tandberg SLR Autoloader SCSI Functional Specifications 1-1 Tandberg Data Overview ______________________________________________________________________ This Page Intentionally Left Blank 1-2 Tandberg SLR Autoloader SCSI Functional Specifications ______________________________________________________________________ 2 SCSI Commands The following table summarizes the command set for the SLR Loader medium changer: OPCODE 07 E7 12 4D 15 1A A5 2B 1E B8 17 03 B5 16 1D B6 00 3B COMMAND INITIALIZE ELEMENT STATUS INITIALIZE ELEMENT STATUS W/RANGE INQUIRY LOG SENSE MODE SELECT MODE SENSE MOVE MEDIUM POSITION TO ELEMENT PREVENT ALLOW MEDIUM REMOVAL READ ELEMENT STATUS RELEASE REQUEST SENSE REQUEST VOLUME ELEMENT ADDRESS RESERVE SEND DIAGNOSTIC SEND VOLUME TAG TEST UNIT READY WRITE BUFFER Tandberg SLR Autoloader SCSI Functional Specifications 2-1 Tandberg Data SCSI Commands ______________________________________________________________________ 2.1 Bit Byte 0 1 2 3 4 5 7 INITIALIZE ELEMENT STATUS 07h 6 5 4 3 2 1 0 Operation Code (07h) Logical Unit Number Reserved Reserved Reserved Reserved Reserved Mode Flag Link The INITIALIZE ELEMENT STATUS command will cause the medium changer to check any relevant element status. A subsequent READ ELEMENT STATUS command may be used to retrieve element status information. Since the medium changer always maintains the current element status information, the default operation of this command only determines if the changer is ready. Mode The setting of the Mode field defines whether or not an inventory is performed by this command: Mode 00b 01b 10b 11b Description Do not re-inventory elements or bar codes, use current valid element status Re-inventory bar codes only, if bar code reader is enabled Do not re-inventory elements or bar codes, use current valid element status Re-inventory all elements and bar codes, if bar code reader is enabled 2-2 Tandberg SLR Autoloader SCSI Functional Specifications Tandberg Data SCSI Commands ______________________________________________________________________ 2.2 Bit Byte 0 1 2 3 4 5 6 7 8 9 7 INITIALIZE ELEMENT STATUS WITH RANGE E7h 6 5 4 3 2 1 0 Logical Unit Number Element Address (MSB) Operation Code (E7h) Reserved Range Element Address (LSB) Reserved Reserved Number of Elements (MSB) Number of Elements (LSB) Mode Reserved Reserved Flag Link The INITIALIZE ELEMENT STATUS WITH RANGE command will cause the medium changer to check the status of the requested range of elements. A subsequent READ ELEMENT STATUS command may be used to retrieve element status information. Since the medium changer always maintains the current element status information, the default operation of this command only determines if the changer is ready. Range A Range bit of zero indicates that all elements are to be initialized. A Range bit of one indicates that the range of elements specified by the Element Address and the Number of Elements fields are to be initialized. Element Address This field specifies the address of the element or the starting address of the range of elements to be checked. This field is ignored when the Range bit is zero. Number of Elements This field specifies the maximum number of elements to be checked. This field is ignored when the Range bit is zero. Mode The setting of the Mode field defines whether or not an inventory is performed by this command: Mode 00b 01b 10b 11b Description Do not re-inventory elements or bar codes, use current valid element status Re-inventory bar codes only, if bar code reader is enabled Do not re-inventory elements or bar codes, use current valid element status Re-inventory all elements and bar codes, if bar code reader is enabled Tandberg SLR Autoloader SCSI Functional Specifications 2-3 Tandberg Data SCSI Commands ______________________________________________________________________ 2.3 Bit Byte 0 1 2 3 4 5 7 INQUIRY 12h 6 5 4 3 2 1 0 Logical Unit Number Vendor Unique Operation Code (12h) Reserved Page Code Reserved Allocation Length Reserved EVPD Flag Link The INQUIRY command requests that information regarding parameters of the medium changer be sent to the initiator. EVPD An enable vital product data (EVPD) bit of zero specifies that the target shall return the standard INQUIRY data. An EVPD bit of one specifies that the device shall return the vital product data based on the Page Code field. Page Code The page code field is used to specify which page of vital product data to return if the EVPD bit is set to one. Page Code 00h 80h Page Description List of supported VPD pages Unit Serial Number page Allocation Length This specifies the maximum number of bytes that the initiator has allocated for returned Inquiry data. An Allocation Length of zero indicates that no Inquiry data is transferred. This condition is not considered an error. The device will terminate the DATA IN phase when allocation length bytes have been transferred, or when all available Inquiry data has been transferred to the initiator, whichever is less. 2-4 Tandberg SLR Autoloader SCSI Functional Specifications Tandberg Data SCSI Commands ______________________________________________________________________ 2.3.1 Standard Inquiry Response The following information is returned in response to an INQUIRY command with the EVPD bit set to zero: Bit Byte 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32-35 36-46 47-51 52 53 54 55 7 6 5 4 3 2 1 0 Peripheral Qualifier RMB ISO Version AENC TrmIOP RelAdr Wbus32 Vendor ID Product ID Peripheral Device Type Device-Type Modifier ECMA Version ANSI-Approved Version Reserved Response Data Format Additional Length Reserved Reserved WBus16 Sync Linked Reserved CmdQue SftRe "T" or "O" or "X" "A" or "V" or "X" "N" or "E" or "X" "D" or "R" or "X" "B" or "L" or "X" "E" or "A" or "X" "R" or "N" or "X" "G" or "D" or "X" "S" or "L" or "X" "L" or "X" or "X" "R" or "B" or "X" "" or "" or "X" "A" or "" or "X" "U" or "" or "X" "T" or "" or "X" "O" or "" or "X" "L" or "" or "X" "O" or "" or "X" "A" or "" or "X" "D" or "" or "X" "E" or "" or "X" "R" or "" or "X" "" or "" or "X" "" or "" or "X" Firmware Revision Level Firmware Creation Date Vendor Unique Boot Code Revision Level Firmware Download Size Product Class Vendor Unique BarCode Peripheral Qualifier & Peripheral Device Type These fields identify the physical device currently connected to the logical unit. If the logical unit number is zero, this byte will be set to 08h, indicating the medium changer device. If the logical unit is not zero, this byte will be set to 7Fh, indicating that no device is attached to this logical unit. Tandberg SLR Autoloader SCSI Functional Specifications 2-5 Tandberg Data SCSI Commands ______________________________________________________________________ RMB A removable medium (RMB) bit of one indicates that the medium is removable. Device Type Modifier The device type modifier field is a seven bit device-specific code. This field is set to zero. ISO Version This field indicates the level of compliance with ISO. A value of 01b indicates compliance with the ISO version of SCSI (ISO IS 9316). This field is always set to 01b. ECMA Version This field indicates the level of compliance with ECMA. A value of 001b indicates compliance with the ECMA version of SCSI (ECMA-111). This field is always set to 001b. ANSI-Approved Version This field indicates the level of compliance with ANSI. A value of 010b indicates compliance with the SCSI-2 standard X3.131-1994. This field is always set to 010b. AENC An AENC bit of zero indicates that the device does not support asynchronous event notification. This bit shall always be set to zero. TrmIOP A terminate I/O process (TrmIOP) bit of zero indicates that the device does not support the TERMINATE I/O PROCESS message. This bit shall always be set to zero. Response Data Format This field is always set to 2h, indicating compliance with SCSI-2. Additional Length The additional length field specifies the length in bytes of the parameters. If the allocation length of the CDB is too small to transfer all of the available parameters, the additional length field is not adjusted to reflect the truncation. RelAdr A relative address (RelAdr) bit of zero indicates that the device does not support relative addressing. WBus32 A wide bus 32 (WBus32) bit of zero indicates that the device does not support 32-bit wide data transfers. WBus16 A wide bus 16 (WBus16) bit of zero indicates that the device does not support 16-bit wide data transfers. A WBus16 bit of one indicates that the device supports 16-bit wide data transfers. 2-6 Tandberg SLR Autoloader SCSI Functional Specifications Tandberg Data SCSI Commands ______________________________________________________________________ Sync A synchronous transfer (Sync) bit of one indicates that the device supports synchronous data transfer. Linked A linked bit of zero indicates that the device does not support linked commands. CmdQue A command queuing (CmdQue) bit of zero indicates that the device does not support command queuing. SftRe A soft reset (SftRe) bit of zero indicates that the device responds to the RESET condition with the hard RESET alternative. Vendor Identification The vendor identification field contains ASCII data, left Justified, padded to the right with ASCII space characters (20h). The returned parameter data from the vendor identification string is user programmable from the SLR Autoloader operator control panel SETUP, SCSI, Vendor ID menu. The vendor identification can be either "TANDBERG" or "OVERLAND" or "XXXXXXXX" where "X" is unique user programmed ASCII data. The default vendor ID string is "TANDBERG". Product Identification The product identification field contains ASCII data, left justified, padded to the right with ASCII space characters (20h). The returned parameter data from the product identification string is user programmable from the SLR Autoloader operator control panel SETUP, SCSI, Product ID menu. The product identification can be either "SLR AUTOLADER " or "LXB " or "XXXXXXXXXXXXXXXX" where "X" is unique user programmed ASCII data. The default product ID string is "SLR AUTOLOADER". Firmware Revision Level This field contains the revision level of the control firmware (ASCII data). Firmware Creation Date This field contains the creation date of the control firmware (ASCII data) Boot Code Revision Level This field contains the revision level of the boot code. Firmware Download Size This field specifies the size of the firmware image file required for a firmware download operation. A value of 02h indicates a 1MB file size. Product Class This field is set to 02h to indicate an SLR Library product. BarCode This field is set to 01h (LSBof Byte 55 set) if the bar code scanner is enabled in the library. Tandberg SLR Autoloader SCSI Functional Specifications 2-7 Tandberg Data SCSI Commands ______________________________________________________________________ 2.3.2 Supported Vital Product Data Page 00h The supported vital product data page (Page Code 0) returns the list of vital product data pages implemented by the target Bit Byte 0 1 2 3 4 5 7 6 Peripheral Qualifier 5 4 3 2 1 0 Peripheral Device Type Page Code (00h) Reserved Page Length Page 0 (00h) Page 80 (80h) 2.3.3 Unit Serial Number Page 80h The unit serial number page (Page Code 8h0) returns the medium changer device serial number. Bit Byte 0 1 2 3 4 5 6 7 8 9 10 11 12 13 7 6 Peripheral Qualifier 5 4 3 2 1 0 Unit Serial Number Peripheral Device Type Page Code (80h) Reserved Page Length "2" "B" or "U" "Y" "W" "W" "X" "X" "X" "X" "X" Peripheral Qualifier & Peripheral Device Type These fields identify the physical device currently connected to the logical unit. If the logical unit number is zero, this byte will be set to 08h, indicating the medium changer device. If the logical unit is not zero, this byte will be set to 7Fh, indicating that no device is attached to this logical unit. Unit Serial Number The value returned for this field is the serial number (ASCII data) for the library, as set from the operator panel. Byte 5: Byte 6: Byte 7: Byte 8: Plant of manufacture B = San Diego, U = UK WhereY equals last digit of the year of manufacture Where W equals the first numeric digit of the week of manufacture Where W equals the second numeric digit of the week of manufacture 2-8 Tandberg SLR Autoloader SCSI Functional Specifications Tandberg Data SCSI Commands ______________________________________________________________________ 2.4 Bit Byte 0 1 2 3 4 5 6 7 8 9 7 LOG SENSE 4Dh 6 5 4 3 2 1 0 Logical Unit Number PC Operation Code (4Dh) Reserved Page Code Reserved Reserved PPC SP Parameter Pointer (MSB) Parameter Pointer (LSB) Allocation Length (MSB) Vendor Unique Reserved Allocation Length (LSB) Flag Link The LOG SENSE command provides a means for the initiator to retrieve statistical information maintained by the device. PPC The parameter pointer control (PPC) bit controls the type of parameters requested from the target. A PPC bit of zero indicates that the log parameter requested shall begin with the parameter code specified in the parameter pointer field and shall return the number of bytes specified in the allocation length field in ascending order of parameter codes from the specified log page. This bit should always be set to zero. SP A save parameters (SP) bit of zero indicates that parameters shall not be saved. This bit should always be set to zero. PC The page control (PC) field specifies the type of parameter values to be selected: PC 01b Parameter Value Cumulative values All other PC values are not supported. PAGE CODE The page code field identifies which log page is being requested by the initiator. Valid values are: Page Code 00h 2Eh 30h 31h 32h Page Description List of supported pages TapeAlert Log Page System Trace Page System Log Page System Configuration Page Tandberg SLR Autoloader SCSI Functional Specifications 2-9 Tandberg Data SCSI Commands ______________________________________________________________________ PARAMETER POINTER The parameter pointer field allows the initiator to request parameter data bytes beginning from a specific parameter code to the maximum allocation length or maximum parameter code supported by the device, whichever is less. Log parameters within the specified page shall be transferred in ascending order according to parameter code. This field should always be set to zero. ALLOCATION LENGTH The allocation length field specifies how much space the initiator has allocated for returned data. 2.4.1 LOG SENSE Page Format Log sense data is organized in pages. The data for only one page can be transferred with any one LOG SENSE command. The Log Sense page consists of a 4-byte page header followed by zero or more log parameters. Each log parameter is made up of a 4-byte parameter header followed by one or more associated parameter data bytes. 2.4.2 LOG SENSE Page Header Format Each log page begins with a four-byte page header followed by zero or more variable length log parameters defined for that page. Bit Byte 0 1 2 3 4-n 7 Reserved 6 5 4 3 Page Code Reserved 2 1 0 Page Length (MSB) Page Length (LSB) Page-specific log parameter(s) PAGE CODE The page code field identifies which log page is being transferred. PAGE LENGTH The page length field specifies the length in bytes of the following log parameters. If the initiator sends a page length that results in the truncation of any parameter, the target shall terminate the command with CHECK CONDITION status. The sense key shall be set to ILLEGAL REQUEST with the additional sense code set to INVALID FIELD IN PARAMETER LIST. 2-10 Tandberg SLR Autoloader SCSI Functional Specifications Tandberg Data SCSI Commands ______________________________________________________________________ 2.4.3 LOG SENSE Page 00h Format The supported log page (Page Code 0) returns the list of log pages implemented by the target Bit Byte 0 1 2 3 4 5 6 7 8 7 Reserved 6 5 4 3 2 1 0 Page Code (00h) Reserved Page Length (LSB) Page 0 (00h) Page 2Eh Page 30h Page 31h Page 32h Page Length(MSB) 2.4.4 Bit Byte 0 1 2 3 5n-1 5n 5n+1 5n+2 5n+3 7 LOG SENSE Page 2Eh Format 6 Reserved 5 4 3 2 1 0 Page Code (2Eh) Reserved Page Length (LSB) TapeAlert Flag Format Page Length (MSB) Parameter Code (MSB) DU (0) DS (1) TSD (0) ETC (0) TMC (0) Parameter Length (1) Flag Value Parameter Code [n] (LSB) Reserved LP (0) Log Sense Page 2Eh returns the TapeAlert log page information for the device. Log Sense Page 2Eh will return the 64 TapeAlert flags as defined in the TapeAlert Specification V2.0. The device implements the following TapeAlert flags: NUMBER 1 2 4 13 14 15 16 18 23 FLAG NAME Library Hardware A Library Hardware B Library Hardware D Library Pick Retry Library Place Retry Library Load Retry Library Door Library Magazine Library Scan Retry TYPE Critical Warning Critical Warning Warning Warning Critical Critical Warning FLAG DESCRIPTION Drive Communications Error Library Mechanism Error Library Hardware Fault Library Pick Retries have occurred Library Place Retries have occurred Library Load Retries have occurred Library Door is Open Library Magazine not Present Library Barcode Scan Retries have occurred Tandberg SLR Autoloader SCSI Functional Specifications 2-11 Tandberg Data SCSI Commands ______________________________________________________________________ The value for any flag that is not implemented will always be set to zero. · · · · · Each flag will be cleared to zero in the following circumstances: At device power on When the TapeAlert log page 2Eh is read When the specified corrective action has been taken On a SCSI bus reset or Bus Device Reset message Parameter Code The parameter code field specifies the TapeAlert flag number. DU A Disable Update (DU) bit of zero indicates that the target shall update the log parameter value to reflect all events that should be noted by that parameter DS A Disable Save (DS) bit of one indicates that the target does not support saving the log parameter value in response to a LOG SENSE command with the SP bit set to one. TSD A Target Save Disable (TSD) bit of zero indicates that the target provides a target-defined method for saving the log parameter ETC An Enable Threshold Comparison (ETC) bit of zero indicates that a threshold comparison is not performed. TMC The Threshold Met Criteria field is not valid when the ETC bit is zero. LP A List Parameter bit of zero indicates that the parameter code is a data counter. Parameter Length The parameter length field defines the length of the parameter data. This field is always set to 01h for the TapeAlert flags. Flag Value A Flag Value of 00h indicates that the specific TapeAlert flag is cleared. A flag value of 01h indicates that the specific TapeAlert flag is set. Flag values 02h-FFh are reserved. 2-12 Tandberg SLR Autoloader SCSI Functional Specifications Tandberg Data SCSI Commands ______________________________________________________________________ 2.4.5 Bit Byte 0 1 2 3 4-n 7 LOG SENSE Page 30h, 31h, 32h Format 6 Reserved Reserved 5 4 3 Page Code 2 1 0 Page Length (MSB) Page Length (LSB) Page-specific log parameter(s) Log Sense Page 30h returns a device specific listing of the Library System Trace information. Log Sense Page 31h returns a device specific listing of the Library System Log information. Log Sense Page 32h returns a device specific listing of the Library System Configuration information. The format of this data is not defined by this document and is intended for use by factory personnel. Tandberg SLR Autoloader SCSI Functional Specifications 2-13 Tandberg Data SCSI Commands ______________________________________________________________________ 2.5 Bit Byte 0 1 2 3 4 5 7 MODE SELECT 15h 6 5 4 3 2 1 0 Logical Unit Number Vendor Unique Operation Code (15h) PF Reserved Reserved Parameter List Length Reserved Reserved SP Flag Link The MODE SELECT command provides a means for the initiator to specify medium, logical unit, or peripheral device parameters to the target. PF The Page Format bit, when set to one, indicates that the data sent by the host after the MODE SELECT header and block descriptors complies with the definition of pages in the SCSI-2 specification. If the PF bit is set to zero, only the header is defined for the MODE SELECT data. SP A save pages (SP) bit of zero indicates the target shall perform the specified MODE SELECT operation, and shall not save any pages. An SP bit of one indicates that the current configuration values specified by this command are saved in nonvolatile memory and used for subsequent operations. PARAMETER LIST LENGTH This specifies the length in bytes of the MODE SELECT parameter list that is transferred during the DATA OUT phase. A zero parameter list length indicates that no data is to be transferred. 2.5.1 MODE SELECT Parameter List The MODE SELECT parameter list contains a 4-byte header followed by zero or more variable length pages. MODE SELECT Header Bit Byte 0 1 2 3 7 6 5 4 Reserved Reserved Reserved Reserved 3 2 1 0 All fields in the parameter list header are reserved and must be set to zero. 2-14 Tandberg SLR Autoloader SCSI Functional Specifications