Clark,

I don't know where it is written up, but it has been this way as long as I
can remember, which is 5 minutes when I go to the shop, and a bit longer for
IDCAMS.

Following example look at the CISZ(32768) versus the physical record size
(16384). Physical record size is the block size used for each record on the
track, so each CI uses two blocks or records and can span a track boundary.

DATA ------- HAWKINS.KSDS.DATA

  IN-CAT --- CATALOG.VHDSUSR

  HISTORY

    DATASET-OWNER-----(NULL)     CREATION--------2018.019

    RELEASE----------------2     EXPIRATION------0000.000

    ACCOUNT-INFO-----------------------------------(NULL)

  PROTECTION-PSWD-----(NULL)     RACF----------------(NO)

  ASSOCIATIONS

    CLUSTER--HAWKINS.KSDS

  ATTRIBUTES

    KEYLEN----------------44     AVGLRECL-------------435
BUFSPACE----------530432     CISIZE-------------32768 
    RKP--------------------0     MAXLRECL------------2040
EXCPEXIT----------(NULL)     CI/CA-----------------22 
    SHROPTNS(3,3)      SPEED     UNIQUE           NOERASE     INDEXED
NOWRITECHK     UNORDERED        NOREUSE 
    NONSPANNED

  STATISTICS

    REC-TOTAL--------------0     SPLITS-CI--------------0
EXCPS------------------0                              
    REC-DELETED------------0     SPLITS-CA--------------0
EXTENTS----------------1                              
    REC-INSERTED-----------0     FREESPACE-%CI----------0
SYSTEM-TIMESTAMP:                                     
    REC-UPDATED------------0     FREESPACE-%CA----------0
X'0000000000000000'                              
    REC-RETRIEVED----------0     FREESPC-----------720896

  ALLOCATION

    SPACE-TYPE------CYLINDER     HI-A-RBA----------720896

    SPACE-PRI--------------1     HI-U-RBA---------------0

    SPACE-SEC--------------1

  VOLUME

    VOLSER------------HDSUS5     PHYREC-SIZE--------16384
HI-A-RBA----------720896     EXTENT-NUMBER----------1 
    DEVTYPE------X'3010200F'     PHYRECS/TRK------------3
HI-U-RBA---------------0     EXTENT-TYPE--------X'40' 
    VOLFLAG------------PRIME     TRACKS/CA-------------15

    EXTENTS:

    LOW-CCHH-----X'00060000'     LOW-RBA----------------0
TRACKS----------------15                              
    HIGH-CCHH----X'0006000E'     HIGH-RBA----------720895



Ron 


-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On
Behalf Of Clark Morris
Sent: Tuesday, January 16, 2018 9:01 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: [IBM-MAIN] VSAM Performance - CPU reduction

[Default] On 16 Jan 2018 06:54:52 -0800, in bit.listserv.ibm-main
ronjhawk...@sbcglobal.net (Ron hawkins) wrote:

>Tim,
>
>Things changed a couple of decades ago.
>
>VSAM physical block is not always the same as the CISZ. 
>
>32K CISZ does not waste any space on the track. 

Where is this written up?  Being retired, I missed this and didn't realize
this was true on the OS390 system I worked on in the 1990s.

Clark Morris
>
>Ron
>
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