MS SQL Server inconsistency with READ UNCOMMITTED *and* READ COMMITTED - How about DB2 i?

All,

Run across a couple interesting articles about MS SQL Server that
honestly surprised the heck out of me :)
"Timebomb - The Consistency problem with NOLOCK / READ UNCOMMITTED"
http://sqlblogcasts.com/blogs/tonyrogerson/archive/2006/11/10/1280.aspx

"Timebomb - Consistency problem with READ COMMITTED; why you still
multi-count or no count rows"
http://sqlblogcasts.com/blogs/tonyrogerson/archive/2006/11/16/1345.aspx

For additional references, here's the article I started with:
"Actual Emails: Is "NOLOCK is the epitome of evil?""
http://www.sqlservercentral.com/blogs/sqltact/2012/01/21/actual-emails-is-nolock-is-the-epitome-of-evil/

Now my first thought was, that I was glad DB2 for i didn't have such
data consistency errors. I thought the whole point of a RDBMS and SQL
was to get teh right answer to your question without needing to
understand how the DB provides the answer.

But then I realized, I was making an assumption about DB2 for i there.
Granted, the problems describe are not one I've ever seen, and I use
READ UNCOMMITTED and READ COMMITTED a lot. But I don't know enough
about the internals of DB2 to know if a similar situation could occur;
and why or why not it would happen on DB2 for i. (And what about DB2
LUW?)

I'm thinking if my gut's correct, then the answer is no and the reason
has something to do with the SLS architecture and/or the fact that DB2
for i doesn't have clustered indexes. But I thought I throw this
message out there to see if anybody with more knowledge of the DB
internals, (looking at you Chuck! :) would be able to shine a light on
the subject.

Lastly, judging from this post regarding Oracle's transactions isolation levels:
"Ask Tom: On Transaction Isolation Levels"
http://www.oracle.com/technetwork/issue-archive/2005/05-nov/o65asktom-082389.html

As I understand the above, Oracle, due to it's MVCC, doesn't suffer
from the same consistency issues. Oracle basically always works in
the "Snapshot Isolation" level that MS added to SQL Server in 2005.

So DB2 for i gurus, how does DB2 do it?

Charles