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StorageTek SL3000 User's Guide E20875-05 |
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# A Library Addressing

This appendix explains the addressing schemes used in the SL3000 library. There are four main types of addressing schemes:

- Internal Firmware (Library, Rail, Column, Side, Row) — used by the firmware and internal communications to represent all devices and locations within the library.

- HLI-PRC (LSM, Panel, Row, and Column) — used by HLI clients, such as ACSLS and ELS, to represent library locations and components.

- FC-SCSI Element Numbering — used by hosts with FC-SCSI connections to the library.

- External hardware numbering — used for drive bay locations (see "Tape Drive Numbering").

Note: In this appendix, "left" and "right" are in reference to viewing the library from the CAP-side (front) unless otherwise specified.

## CenterLine

Internal firmware and HLI addressing use the centerline as a reference point. When additional modules are added to either end of the library, the existing components do not change address number.

The basis of centerline technology involves balancing additional modules on the left and right side of the Base Module. This reduces the overall travel of the robot to help balance the work load and improve library performance.

Figure A-1 shows the location of the centerline for various library configurations.

Figure A-1 CenterLine Location in Sample Libraries

## Internal Firmware

Internal firmware addressing designates physical location using five parameters: Library, Rail, Column, Side, Row (L,R,C,S,W).

Library

  Always equal to 1.

Rail

  Always equal to 1.

Column

  Indicates the horizontal location of a tape cartridge referenced from the centerline of the library. Numbering is static, allowing modules to be added without renumbering existing columns.

  - Positive (+) value indicates right of centerline

  - Negative (-) value indicates left of centerline

  Base Module

  - Contains columns 1 to 6 for data cartridges and 1 to 4 for tape drives.

  DEM

  - Contains columns -1 to -6 for data cartridges and -1 to -4 for tape drives.

  CEM

  - Contains six columns for data cartridges.

  - Column numbering continues consecutively from the adjacent module. However, if there is no DEM, a CEM placed directly to the left of a Base contains columns -7 to -12 (columns -1 to -6 are skipped).

  PEM

  - Contains only three columns for data cartridges. The outer most three columns are inactive.

  AEM

  - AEM columns are numbered as if a DEM and four CEMS are installed to the left of the Base Module and four CEMs are installed to the right.

  - Left AEM columns are always numbered -33 to -31.

  - Right AEM columns are always 31 to 33.

Side

  Indicates the front or rear walls of the library.

  - Rear wall = 1

  - Front wall = 2

Row

  The vertical location of a tape cartridge, consecutively numbered from the top (1) down (52).

Figure A-2 Internal Firmware Addressing Examples (viewed from top of library)

## HLI-PRC

HLI-PRC addressing designates physical location using four parameters: LSM, Panel, Row, and Column.

LSM

  Always equal to 0.

Panel

  Indicates the front or rear wall of a module. The panel number can range from 0 to 23 depending on the configuration of the library.

  - Rear wall = even numbers

  - Front wall = odd numbers

  The panel location is defined relative to the Base Module (panels 12 and 13). Panel values less than 12 indicate the module is to the left of the Base Module, while values greater than 13 indicate the module is to the right of the Base Module.

  Base Module

  - Panels 12 and 13

  DEM

  - Panels 10 and 11

  CEM

  - Panels are numbered consecutively from the adjacent module. However, if there is no DEM, a CEM placed directly to the left of a Base Module contains panels -8 and -9 (panels -10 and -11 are skipped).

  AEM

  - AEMs are considered CAPs by HLI addressing. Therefore, AEMs have a CAP ID instead of a panel number (see "Cartridge Access Ports - HLI")

  - Left AEM CAP ID is always numbered 0

  - Right AEM CAP ID is always numbered 11

Row

  The vertical location of a slot, consecutively numbered from the top down (0 to 51). However, drive bays have row numbering from 0 to 23 for the Base Module, and 0 to 31 in the DEM.

Column

  The horizontal location of a slot from left to right (0 to 5). However, drive bays always have a column value of 0 (see "Tape Drive Numbering"").

  AEM column numbering starts at the rear wall and runs left to right (columns 0–2), then proceeds to the front wall and runs left to right (columns 3–5).

### Tape Drives and CAPs

HLI addressing defines tape drives with a drive ID instead of a row value. The addressing is LSM, panel, drive ID, column (see "Tape Drive Numbering").

HLI addressing defines CAP locations with a CAP ID instead of a panel value. The addressing is LSM, CAP ID, row, column (see "Cartridge Access Ports - HLI"").

Figure A-3 HLI-PRC Addressing Examples (viewed from top of library)

## FC-SCSI Element Numbering

For FC-SCSI element numbering, each active component in the library is defined by a unique element ID number. SCSI element numbering consists of three element types:

- Storage Elements (active cartridge slots)

  - Begins at 2000 and increments by one for every active slot.

  - Numbered top to bottom, left to right, and rear to front. See Figure A-4.

- Import/Export Elements (rotational CAPs)

  - Begins at 10 for the left most CAP in the library. Storage and Import/Export elements are numbered sequentially by slot. No slots are skipped.

  - Numbered top to bottom, left to right. See Figure A-7.

- Data Transfer Elements (tape drives)

  - Begins at 1000 and increments by one for every installed tape drive.

  - Numbered left to right, top to bottom, starting at the centerline in the Base module and continuing in the DEM if installed. This numbering scheme allows the user to add a bank of drives and not disturb the ordering of the banks above. See Figure A-5.

    Note: When the library powers on, a vacant drive slot will not be included in the element number sequence. Open Systems backup applications do not tolerate Data Transfer Elements that cannot or do not respond when you power-on the library.

The behavior of the FC-SCSI element numbering depends on the whether the library is partitioned and if the active capacity was assigned by default or was user-selected.

### Default Capacity Assignment

When active capacity is assigned by default, the library always begins the active capacity from the upper left slot on the rear wall of the left-most module. The activated capacity and SCSI numbering scheme follows the pattern defined in Figure A-4. The default SCSI element numbering for tape drives follows the numbering scheme defined in Figure A-5.

With default numbering, any configuration change to the library causes the element numbers to be reassigned. Therefore, the element numbers will be reassigned and the library will reboot when:

- A storage module is added/removed from the library

- Activated capacity changes

- Tape drives are added/removed

### User Defined—Non-Partitioned Capacity Assignment

When the active capacity location is selected by the user in a non-partitioned library, the numbering begins with the left most slot on the rear wall within the selected active area. The numbering scheme follows the pattern defined in "Default SCSI Storage Element Numbering Scheme" for all active slot cells, but skips over any inactive cells.

If additional capacity is activated, the SCSI numbering of previously activated cells does not change — the library simply appends the SCSI numbering for newly activated cells (see Figure A-8 and Figure A-9 ).

However, if tape drives are added to a user-defined, non-partitioned library, the library reassigns SCSI Data Transfer element numbering following the "Default SCSI Data Transfer Element Numbering Scheme". Then, the library reboots

### User Defined—Partitioned Capacity Assignment

When the active capacity location is selected by the user in a partitioned library, the numbering begins with the left most slot on the rear wall within the partition. The numbering scheme follows the pattern defined in Figure A-4 for all active slot cells, but skips over any inactive cells and cells not within the partition. Therefore, element numbering is continuous within each partition, even if cell locations for the partition are not adjacent.

If additional capacity is activated or tape drives are added to a partition, the SCSI numbering of previously numbered elements in the partition does not change. The library simply appends the SCSI numbering for newly activated cells or newly inserted tape drives within the partition.

### Default SCSI Storage Element Numbering Scheme

Figure A-4 shows the default numbering scheme for SCSI Storage Elements. The numbering scheme follows these rules:

1. The numbering starts in the upper left slot on the rear wall of the left-most module.

2. The numbering increases from top to bottom and left to right.

3. When the numbering reaches the last slot on the rear wall, it crosses to the front wall of the left-most module (A to B in Figure A-4).

4. The numbering continues top to bottom, left to right, and ends at the lower right slot of the right-most module.

Figure A-4 SCSI Storage Element Numbering

### Default SCSI Data Transfer Element Numbering Scheme

Figure A-5 shows the default numbering scheme for SCSI Data Transfer Elements. The numbering scheme follows these rules:

1. The numbering starts in the upper left drive slot in the Base Module.

2. The numbering increases from left to right and top to bottom (skipping any empty drive slots).

3. When the numbering reaches the lower right drive slot on the Base Module, it crosses to the Drive Expansion Module (A to B in Figure A-5).

4. The numbering continues left to right, top to bottom, and ends at the lower right slot of the DEM.

Figure A-5 SCSI Data Transfer Element Numbering (viewed from front of library)

### Element Numbering Examples

The library in the example has been simplified and is not an exact representation of a SL3000 library.

#### Default Numbering

Figure A-6 and Figure A-7 provide an example of default SCSI element numbering. The example library includes:

- Four modules: one Base, one DEM, and two CEMs

- 166 data cartridge slots: numbered 2000 to 2165

- 40 tape drive bays (two tape drives are missing, one in each module): numbered 1000 to 1037

- Two CAPs, each with seven slots: numbered 10 to 23

Figure A-6 SCSI Element Numbering - Rear Wall (viewed from front of library)

Figure A-7 SCSI Element Numbering - Front Wall (viewed from front of library)

#### User-Defined Numbering

Figure A-8 and Figure A-9 provide an example of user-defined SCSI element numbering. The library in the example has been simplified and is not an exact representation of a SL3000 library. For simplification, the active areas selected are only on the rear wall.

For this example, the user has decided to activate 50 cells, beginning with the DEM. As a result, the SCSI storage element numbering begins at 2000 with the upper left-most active cell in the DEM. The cells in the left CEM are currently inactive and are therefore not numbered (Figure A-8).

Figure A-8 User Defined Capacity SCSI Element Numbering - Rear Wall

At a later date, the user decides to activate the remaining 30 cells in the library. Since the active capacity was initially user-defined, the SCSI numbering does not re-assign numbering to the previously-activated cells. The SCSI storage element numbering for the newly-activated cells is appended (Figure A-9).

Figure A-9 User Defined Added Capacity SCSI Element Numbering - Rear Wall

## Comparison of Addressing Schemes

Internal Firmware

- Uses: library, rail, column, side, and row.

- Begins at 1 and uses negative numbers.

- Side indicates the front or rear wall of the library.

- Drive bays have column values 1 to 4 (BM) and -1 to -4 (DEM).

HLI-PRC

- Uses: LSM, panel, row, and column.

- Begins at 0 with no negative numbers.

- Panel indicates the front or rear wall of a specific module.

- Drive bays always have column value of 0.

FC-SCSI Element

- Uses single positive number for the element ID.

- Cartridge slots begin at 2000, tape drives begin at 1000, CAPs begin at 10.

- Inactive slots and empty drive bays are skipped when element numbers are assigned.

- Default element numbering is reassigned with any library configuration change.

- Element numbering is dependent on active capacity.

## Tape Drive Numbering

All of the tape drives in the SL3000 library are physically located at the rear of the Base Module or Drive Expansion Module. There are four addressing schemes used to define the location of drives:

- "Hardware Numbering"

- "Internal Firmware"

- "HLI-PRC"

- FC-SCSI Element numbering (see "Default SCSI Data Transfer Element Numbering Scheme").

### Hardware Numbering

The physical hardware numbering of tape drives is assigned by the HBC controller card. The card automatically assigns a number, 1-56, to each drive bay.

Note: The perspective in Figure A-10 is from the drive-side (rear) of the library.

Figure A-10 Tape Drive Physical Hardware Numbering (viewed from rear of library)

### Internal Firmware

The firmware addressing (library, rail, column, side, row) distinguishes a drive based on column and row. The library, rail, and side values are always equal to 1.

Note: The perspective in Figure A-11 is from the drive-side (rear) of the library.

Figure A-11 Tape Drive Internal Firmware Addressing (viewed from rear of library)

### HLI-PRC

The HLI-PRC uses drive IDs instead of row values. Therefore, the addressing is LSM, panel, drive, column. HLI distinguishes a drive based on the panel and drive value. The LSM and column values are always equal to 0.

Note: The perspective in Figure A-12 is from the drive-side (rear) of the library.

Figure A-12 Tape Drive HLI-PRC Addressing (viewed from rear of library)

## Addressing of Components—CAPs and Robots

The addressing of components, such as CAPs and robots, have unique addressing rules:

- The library and rail values are always 1.

- A row value of 0 indicates the address is referring to the device, not a slot in the device.

- The column value of a rotational CAP depends on module location.

Note: "Left" and "right" are in reference to viewing the library from the CAP-side (front) unless otherwise specified.

### Cartridge Access Ports - Internal Firmware

Both rotational CAPs and AEMs are considered cartridge access ports for addressing purposes.

#### Rotational CAPs

Column

  The column value depends on the size of the library and the location of the module that contains the CAP.

  For modules to the left of centerline, the CAP column value corresponds to the second column from the right of the module. For example, in a DEM, the column value for the CAP would be -2 and a CEM to the left of the DEM would have a CAP column value of -8.

  For modules to the right of centerline, the CAP column value corresponds to the fifth column from the left of the module. For example, a CAP in the Base has a column value of 5 and a CEM to the right of the Base would have a CAP column value of 11.

Side

  The side value is always 2, since the CAPs are only located on the front of the module.

Row

  When addressing the device: the row value is 0.

  When addressing a specific slot: the row value is the slot in the CAP magazine (values 1 to 26).

Example - Rotational Firmware Addressing

  For this example, the library has a Base, DEM, and four CEMs (two on each side). The address refers to the sixth cell down in the CAP in the CEM on the far left.

  The firmware address is: (1, 1, -14, 2, 6)

#### AEM CAPs

Column

  The column value when referencing the CAP is:

  - -31 for left AEM

  - 31 for right AEM

  The column value when referencing a slot in the CAP:

  - -31 to -33 for left AEM

  - 31 to 33 for right AEM

Side

  Indicates the front or rear CAP doors on the library.

  - Rear wall = 1

  - Front wall = 2

Row

  When addressing the device: the row value is 0.

  When addressing a specific slot: the row value is the slot in the CAP (values 1 to 26).

Example - AEM CAP Firmware Addressing

  For this example, the address is referencing a cartridge slot in the right AEM. The slot is the 37th down in the far right column in the rear CAP door.

  The firmware address is: (1, 1, 33, 1, 37)

### Cartridge Access Ports - HLI

CAPs have CAP IDs instead of panel values. CAP IDs range from 0 to 11, depending on location.

#### Rotational CAPs

LSM

  Always equal to 0.

CAP ID

  Ranges from 1 to 10

  - CEMs left of centerline = 1 to 4 (left to right)

  - DEM = 5

  - Base Module = 6

  - CEMs right of centerline = 6 to 10 (left to right)

Row

  The value is the slot in the CAP (can be values 0 to 25).

Column

  The value always equals 0.

Example - Rotational CAP HLI Addressing

  For this example, the library has a Base, DEM, and eight CEMs (four on each side). The address refers to the sixth cell down in the CAP in the CEM on the far left.

  The HLI address is: (0, 1, 5, 0)

#### AEM CAPs

LSM

  Always equal to 0.

CAP ID

  Left AEM equals 0.

  Right AEM equals 11.

Row

  The value is the slot in a column (can be values 0 to 38).

Column

  Rear wall = columns 0 to2

  Front wall = columns 3 to 5

### Robots - Internal Firmware

Column

  The column value is always 0.

Side

  If there is only one robot: the side value is always 1.

  For redundant robot configurations:

  - Left robot = 1

  - Right robot = 2

Row

  When addressing the device: the row is 0.

  When addressing the specific slot: the row is the slot value (1).

Example - Robot Firmware Addressing

  For this example, the address is referring to the right robot in a redundant robotics library.

  The firmware address is: (1, 1, 0, 2, 0)