[TransWarp] PEAK Progress Report

Phillip J. Eby pje at telecommunity.com
Mon Nov 11 11:22:33 EST 2002

At 10:02 AM 11/11/02 +0200, Roché Compaan wrote:
>Congratulations and wow!
>On Friday I strangely felt that I should update my PEAK checkout to come
>up to speed with what's been happening in the last couple of months. I
>was chuffed to see your announcement a short while after that.


>I was wondering if you still plan to implement a "Specialist" or should
>one roll your own.

If you look at the TODO, you'll see some stuff about "Rack -> DM".  Ty and 
I have decided to drop both the terms Specialist and Rack, and replace them 
with simply "Data Manager", which although somewhat generic:

1. Directly states what the thing does, and

2. Is the same term used in ZODB to describe an object which participates 
in transactions and/or manages persistent object states.  Our DMs will do both.

So there will be a number of DataManager classes, including perhaps a few 
"AssistantDataManager" classes.  (Ty proposed the latter name as a joke, 
but it has stuck for now in our design discussions.)  "Assistant" DM's are 
objects which locate or retrieve objects from other DM's.  A better term 
for this would probably be good, but we don't have one yet.  Some kinds of 
ADM's include:

* Query DM's, which return PersistentList (or some variant thereof) 
instances based on an oid made up of query parameters

* Alternate key DM's, which look up an object by a unique key other than 
its OID (often used for human-readable keys vs. internal numeric ID's)

* Partial-state DM's, which retrieve or compute state for large, complex, 
or otherwise expensive-to-load portions of an object's state, that should 
only be loaded on demand.

Anyway, if you were wondering what all that stuff about DM classes in the 
TODO file was, now you know.  :)

>I'd also love to help write a do-by-example howto for PEAK early on like
>I did for ZPatterns since you will probably invest more time in
>explaining the conceptual framework initially.

I'm certainly willing to give feedback and clarification on anything you 
write.  As far as new material goes, I'll be focused mainly on the 
tutorial, I think.  Have you seen the work I've done so far in 
docs/core_tutorial?  If you have anything you'd suggest adding, please feel 
free to comment.  Thanks.

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