FCO 62XMX-F002 (DAS), TK50 incompatibility problem (TBK50 cntrlr)

This Field Change Order (FCO 62XMX-F002-DAS) details a solution for an incompatibility issue with TK50 tapes generated on 6000-2XX (62XX) systems. The problem arises because the TBK50 controller (T1034 module) in these systems uses a different soft error recovery routine compared to other TK50 controllers (e.g., TQK50, TUK50, TZK50) found in other system types (e.g., MicroVAX, VX2000, 11/785). This difference prevents tapes created on the 62XX systems from being read correctly on other systems.

The FCO mandates replacing T1034 modules with revisions older than K3 with an updated T1034 module (Part Number EQ-01552-02), bringing them to revision K3, K4, or K5. Before installation, an important note advises screening all existing TK50 tapes created by the VAX 6000 system on a non-TBK50 drive; any tapes with soft errors that are unreadable should be backed up to a mass storage device, as they will remain unreadable on other systems until the FCO is applied. The installation, estimated to take 1 hour, involves a full system shutdown, applying electrostatic discharge (ESD) precautions, physically replacing the T1034 module(s) if their revision is below K3, and then powering up and running diagnostics (EVDYD and EVMDA) to confirm the fix. Finally, the Site Management Guide should be updated to reflect this change.