Re:
>
> Since I was updating a series of credit cards from one tape supplier from a flat file, then if a could preload all the GMAC accounts into memory, then very few access would be made to disk.

I'd consider doing two other things, possibly in addition:

1) sort the flat file first

2) use ADAGER to sort the associated detail dataset(s) (if any)


I'm not sure B-Trees will be of much help ... you're not trying to find what
keys match a pattern ... you *have* the key in your hand!  Essentially,
the B-Tree simply provides a quick way of determining if a particular
key is in the master dataset, or if a particular pattern (e.g., GMAC@)
matches any keys (and, if so, which keys).

Stan Sieler                                           [log in to unmask]
www.allegro.com/sieler/wanted/index.html          www.allegro.com/sieler