Members in one directory block?

[Mike Chantrey]

If I understand correctly, you're asking why load modules do not have statistics in the directory entry. This is because the program which creates them (should be the MVS Binder or linkage editor) is not designed to write such statistics. Also presumably the MVS loader could not cope with a load module with stats in its directory entry - it would not be a valid load module.
This was presumably all decided many years ago before ISPF (and its stats) even existed.

[RonB]

Actually, you CAN specify information to the Binder that will appear in an ISPF member list. When a "SETSSI xxxxxxxx" statement is input to the Binder, ISPF will display its value on the Loadlib Member List ( though you will have to scroll right to see it ). It WILL take an additional 8 bytes in the directory entry.

Ron

[Steve Myers]

The kind of statistics you may be looking for exist inside the load module as an IDR record --



is a Linkage Editor / Binder record - 80xx02 is the key - the xx is a length field.



records the compilers and compile date. These records tend to be quite complex when multiple CSECTS with multiple compilers is involved.

The same data exists in program objects, but extracting it is more complex.

[anindyakg]

Hi all,
I just searched 'directory blocks' in this help board and found this entry.Lots of members have said that the number of members per directory block is fixed and it ranges from 5-6. I created a PDS with 1 directory block and found only 5 members can be accomodated within it.Then I created another PDS with 1 directory block and found it accomodated more than 15 members.In the second PDS the members' are much less in size compared to the members' in the first PDS.Also both the PDS'es have the same primary and secondary extents.I feel that the number of directory blocks does'nt influence the no.of members that can be created.Size of each member matters.I need some insight in this matter.Thanks all.

[Bill Dennis]

Be sure you understand what you are filling up...the directory or the PDS itself.

As I said in my earlier response, the number of members in a directory block is based on the size of the directory entry, not the size of the member data. If your members have ISPF stats, 5 or 6 members fit in one directory blk. If you copy in members with no stats, you could probably fit about 20 members. Load modules have some "userdata" in the directory entry, so one block will hold around 12 members.

Bill

[Ashish Jain]

anindyakg,

Read this posting of Steve Myers carefully...

A directory block has 254 bytes for member entries. A member entry ranges from 12 bytes to 74 bytes. An entry with SPF statistics has 42 bytes. The capacity of the last block of a PDS containing members with SPF statistics is (254-12)/42=5 members. The 12 is because the last block of a directory has one extra pseudo entry to flag the end of data. All other directory blocks contain 254/12=6 entries.

The no. of members in a PDS is decided only by the no. of directory blocks. Whether ISPF STATS is ON or OFF is an important point here.

You were able to create 15 members in one directory block because may be the STATS were off in that PDS.

Try giving STATS ON in any of the member of that PDS and you'll get an error message.

Again the size of a member has nothing to do with the directory block.

[anindyakg]

Hi all,
Thanks all for clearing my idea on directory blocks..particularly Bill and Ashish..I hope to find such good help from this forum in the future.

[Steve Myers]

And don't forget - a PDS-E data set contains only the number of directory blocks required for the members. If the last block fills when adding a member, PDE-E makes a new directory block.

Actually, though IBM does not say this, I don't think a PDSE-E has directory blocks in the traditional sense. I think that a program that reads directory blocks is presented member entries in directory block format.