Using the AEM

The AEM (access expansion module) is essentially a very large CAP that has all of the characteristics of a CAP, such as online/offline states and the ability to be shared by partitions.

The AEM allows you to perform bulk loads or unloads of up to 234 cartridges at a time, to or from the library. It also allows for the non-disruptive maintenance of a library TallBot.

AEMs share many of the features and functions as rotational CAPs, but they also have some unique characteristics. They are:

• Access Door

• Safety Door

• CAP Operations

• Non-Disruptive Maintenance

For detailed information on the AEM, refer to the StorageTek SL3000 Modular Library System User's Guide.

Access Door

The AEM access door is the external door you open to bulk load or unload cartridges to or from the library.

Safety Door

The safety door is the internal “garage door," which lowers to separate the AEM from the rest of the library. This door allows for safe access to the inside of the AEM, either for the library operator to load or unload cartridges, or for a Storage CSE to perform service on the Tallbot or other AEM components.

CAP Operations

The advantages of the AEM is that it allows you to perform the following:

• Bulk enters

  Bulk enters enables to you to enter up to 234 cartridges at a single time.

  You must start a normal enter specifying the AEM cap_id. This can either be a manual enter or you can set the AEM to automatic enter mode.

  In a partitioned library, you can only set a CAP to automatic enter mode if the CAP is dedicated to your partition. Dedicating an AEM to only your partition makes it unavailable to other partitions. Consider other SL3000 users before doing this.

• Bulk ejects

  When ejecting more that 42 volumes to the AEM, the preferred tool for larger ejects is lib_cmd or ejecting.sh. Any other user interface, including cmd_proc, xeject, or an ACSAPI eject will limit the eject load to 42 cartridges at a time. See Using lib_cmd and ejecting.sh.

• Non-disruptive robot maintenance

  Caution:

  When performing a bulk eject using the AEM, ensure all CAP magazines are present. The eject fails if there are missing CAP magazines at locations where ACSLS is attempting to eject cartridges.

  Note:

  The AEM should not to be used for entering or ejecting small numbers of cartridges. It should only be used for bulk enters and ejects.

  Using the AEM for small enters and ejects is much slower since the service safety door must be lowered when the AEM is accessed to enter or remove volumes, and raised when access to the AEM is completed.

  For smaller numbers, use CAPs 1-10. See CAP Numbering.

  Since the AEM should not be used for small enters and ejects, the maximum CAP priority is 1. This aids in preventing the AEM from being selected when the CAP ID is wildcarded with an asterisk on an audit, enter, or eject.

Non-Disruptive Maintenance

The AEM allows the CSE access and service a library TallBot through the use of a safety door (or “garage" door), without having to take the library offline. If the TallBot is defective, it parks itself in the AEM while the library remains online. If redundant TallBots are installed, the library can continue normal operations through the remaining functional TallBot.

The CSE uses a special key to unlock the Service Access lock on the safety door. This causes the AEM safety door to lower, sectioning off the AEM from the rest of the library. Once the safety door is fully down, the CSE opens the AEM safety door and safely performs maintenance on the defective TallBot or other AEM components, while the library remains online. The AEM itself is taken offline during the maintenance period, causing cartridge load/unload functions to be suspended.

When maintenance is complete, the CSE: closes the safety door; the safety door raises; the TallBot is re-initialized and performs an audit to the AEM CAP cartridge slots; and the AEM is brought back online.