Barrie,
I've reviewed the AttributesComponent test and ScalaDocs. Good Job.
Could you do KernelRootPersistenceComponent next? I is finished and just waiting for you. And it might be a bit more interesting. One thing you will want to do in the test is corrupt one of the root blocks and see how it handles it. :-)
In normal operation, a root block can be corrupted perhaps by an incomplete write (root blocks can be long) if a power failure occurs at just the wrong time. Unlikely, but possible. Note that in AW5 all the blocks have a simple checksum, while in AW4 only the root blocks have them. Statistics show that there is on the average a 1 bit corruption for every terabyte of data transfered. In a large operation, that can mean it occurs every day.
Bill