StorageWorks Building Block (SBB) for Disk Drives

This User's Guide outlines the procedures for identifying, handling, removing, and replacing Digital Equipment Corporation's StorageWorks Building Blocks (SBBs) for disk drives.

Key points include:

• Overview: SBBs are modular, SCSI-compatible disk drives.
• Identification: SBBs have a regulatory label (for model number) and a front SBB Identification label providing detailed information such as device model, capacity, SCSI logical unit number (LUN), ID, channel, bus width, shelf compatibility, and data transfer speeds.
• Handling: Proper handling is crucial to prevent damage. SBBs should always be set on their side, handled gently, and never stacked or set on their edge. A critical warning emphasizes waiting at least 30 seconds for high-speed drives (7200 RPM+) to "spin-down" after partial removal to avoid gyroscopic effects causing drops or damage.
• Connectors: SBBs use 96-position DIN sockets designed for reliable power/data sequencing. These connectors are rated for 200 replacement cycles; exceeding this limit can compromise connection integrity and void the warranty.
• Replacement Considerations: Replacing an SBB requires careful consideration of the device type and RAID configuration, as incorrect procedures can lead to data corruption. The SBB identification label should be used to ensure correct replacement.
• Status LEDs: SBBs have green (device activity) and amber (device fault) LEDs. Their ON, OFF, or FLASHING states indicate various operational conditions, including normal activity, inactivity, or different fault scenarios.

• Swap Methods: Three methods for replacing SBBs are detailed, based on controller capabilities and safety:

  • Hot Swap: Power and data are present. Only use if the SCSI controller explicitly supports it to prevent data integrity issues.
  • Warm Swap: Power is present, but no data. Requires quiescing the bus and ensuring the green activity LED is OFF.
  • Cold Swap: Neither power nor data is present. Requires powering off both the shelf and the SCSI bus controller.

• Replacement Procedure: The general process involves releasing mounting tabs, carefully pulling the SBB (while observing the spin-down wait time), inserting a replacement of the exact same model, and verifying the LED status. Warnings about delicate handling, avoiding electrostatic discharge (ESD), and not opening the SBB (which voids the warranty) are also provided.