On Fri, 20 Nov 2015 08:11:08 -0700, Sri h Kolusu wrote:

>>>>Does it at least sort the list in descending order? 
>
>Descending order of what? member names or Size? Why exactly do you need to 
>sort the list ? Do you think it would make a difference to the directory 
>blocks?

Member names. The reason would be that a PDS directory is maintained in order, 
and the directory is always kept compressed.

Whenever a member is deleted from a PDS, the following directory entries are 
all 
shifted to the left. Then, if there is enough space at the end of that 
directory 
block, the first entry from the next block is moved to that space, and the 
process 
repeats to the end of the directory.

As a result, there is less I/O if they are deleted starting at the end of the 
directory. 
This is especially true if there are a lot of members in the PDS.

-- 
Tom Marchant

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