Improve the performance of CRUISE TOP file address exchange

In the first phase of RESTORE, the BFA Capture tapes are read and each data block is filed to new pool and cross-reference files are updated. Following the tape “roll in” phase, there is a phase called address exchange or “fad exchange” where old imbedded file addresses in the restored blocks are replaced with new file addresses where the data copied to. In “part one” of the fad exchange, the old FROM address references in new pool records are replaced by the new pool address where the old data was restored. This part is multi-threaded and is load balanced among I-streams. This part is the most efficient and speediest part of the restore.
In “part two” of the fad exchange the FIXED file blocks that were originally copied to POOL addresses references (or TOP as CRUISE calls it). This part is handled by a single ECB, which by definition implies the process is running on 1 I-stream. This is a serious bottleneck, but how serious it depends on the data profile. This process should be improved to work in the same way as the FROM file address exchange. It needs to be multi-threaded and load balanced across all available I-streams. In the current implementation this is a serious bottle-neck and significantly degrades the performance of the restore, depending on the no. of fixed record addresses to be swapped.