Tracy writes:

<snip>

> but what about the backspace bit?  If we have only forward-pointing links,
> how is backward possible or even seemingly possible?  Only one answer comes
> to mind: if you load the file in the same sequence as the key you're using,
> the physical backspace appears to work.  but what about a different key?
>
> I'd sure love to be wrong about this: it would be just great to really
> backspace, even if locks are required.
>
> Tracy Pierce

There technically are no links, it's a tree and when you go forwards or backwards
the tree is searched. The key used is one that last  positioned the pointer.

One small difference between CM and NM ksam is that CM ksam preserves the
path table that was used to position the key where it is. So if someone deletes a
record out from under a process then CM ksam knows how it came to be pointing
where it is and can logically reposition. NM ksam cannot save its path table across
calls and so in that scenario you get an FSERR 170.

hth,

Bill

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