COPYRIGHT (C) 1984-2018 MERRILL CONSULTANTS DALLAS TEXAS USA

MXG NEWSLETTER FIFTY-FIVE

***********************NEWSLETTER FIFTY-FIVE****************************
                                                                        
                                                                        
                                                                        
                                                                        
          MXG NEWSLETTER NUMBER FIFTY-FIVE, JAN 20, 2010                
                                                                        
Technical Newsletter for Users of MXG :  Merrill's Expanded Guide to CPE
                                                                        
                         TABLE OF CONTENTS                              
                                                                        
I.    MXG Software Version.                                             
II.   MXG Technical Notes                                               
III.  MVS, aka z/OS, Technical Notes                                    
IV.   DB2 Technical Notes.                                              
V.    IMS Technical Notes.                                              
VI.   SAS Technical Notes.                                              
VI.A. WPS Technical Notes.                                              
VII.  CICS Technical Notes.                                             
VIII. Windows NT Technical Notes.                                       
IX.   z/VM Technical Notes.                                             
X.    Email notes.                                                      
XI.   Incompatibilities and Installation of MXG.                        
         See member CHANGES and member INSTALL.                         
XII.  Online Documentation of MXG Software.                             
         See member DOCUMENT.                                           
XIII. Changes Log                                                       
     Alphabetical list of important changes                             
     Highlights of Changes  - See Member CHANGES.                       
                                                                        
     COPYRIGHT (C) 1984,2010 MERRILL CONSULTANTS DALLAS TEXAS USA       
                                                                        
I.  The 2010 Annual Version MXG 27.27 is dated Jan 20, 2010.            
                                                                        
    All sites were mailed a letter with the ftp download instructions.  
    The availability announcement was posted to both MXG-L and ITSV-L.  
    You can always request the current version using the form at        
     http://www.mxg.com/ship_current_version.                           
                                                                        
 1. The current version is MXG 27.27, dated Jan 20, 2010.               
                                                                        
    See CHANGES member of MXG Source, or http://www.mxg.com/changes.    
                                                                        
II.  MXG Technical Notes                                                
                                                                        
                                                                        
 3.  SAS option COMPRESS=YES impact on z/OS MXG Execution.              
                                                                        
     The MXG default for all platforms is COMPRESS=YES. For all ASCII   
     platforms benchmarks have proven that IS correct and desirable: on 
     ASCII systems, COMPRESS=YES minimizes both disk space and CPU time 
     needed to create MXG datasets.                                     
                                                                        
     On z/OS, while COMPRESS=YES does minimize disk space required, it  
     does require additional CPU time. So, like most performance issues,
     it all depends - on whether your disk space is the limiting factor 
     (in spite of the incredible reduction in the real costs for disks) 
     or if the CPU Time consumption is of more concern (at 3am??).      
                                                                        
     At CMG 2009, Chuck Hopf reported an MXG tailoring that set option  
     COMPRESS=NO for the SMF/SORT processing to a TEMPPDB to save CPU   
     time, followed by a PROC COPY with COMPRESS=YES to minimize the    
     size of the output PDB data library.  But then I discovered that in
     SAS V9, COMPRESS=YES can be specified on a LIBNAME statement, which
     eliminated the tailoring, the TEMPPDB and the PROC COPY. Chuck then
     reran these tests, reading an 11GB SMF file, always compressing the
     the output PDB library:                                            
                                                                        
                                                                        
     Compress Option CPUTM   WORK   PDB  CICSTRAN DB2ACCT PDBTEMP TOTAL 
                      sec     cyl   cyl    cyl     cyl     cyl     cyl  
                                                                        
     YES, GLOBAL      2745   2441   1813   1223    2765           8242  
     NO, PROC COPY    1867   6934   1816   5114   10046    6006  29916  
     NO, LIBNAME YES  2376   6934   1816   1223    2765          12737  
     NO, TAPE         2061   6934   1816   TAPE    TAPE           8750  
                                                                        
                                                                        
     The COMPRESS=YES option minimizes the total disk space for all of  
     the output data libraries AND for the WORK library, but at a cost  
     of 15 minutes more CPU time, from 31 to 46, a 48% increase.        
                                                                        
     To save those 15 CPU minutes using COMPRESS=NO+PROC COPY for only  
     the PDB library, the total disk space for the job increased from   
     8242 to 29,916 cyls, nearly four times, and the output libraries   
     increased nearly three times, from 5801 to 16976 cylinders.        
                                                                        
     The intermediate choice, using COMPRESS=NO for WORK library with   
     COMPRESS=YES on the three output LIBNAMES, saves 8 minutes CPU Time
     (or an increase of 27% from the minimum); the total disk space for 
     the job increased only by 50%, from 8242 to 12,737 cylinders, and  
     that increase was all in the uncompressed temporary WORK library   
       //SYSIN DD *                                                     
        OPTIONS COMPRESS=NO;                                            
        %LET PDB2ACC=DB2ACCT;                                           
        LIBNAME PDB      COMPRESS=YES;                                  
        LIBNAME DB2ACCT  COMPRESS=YES;                                  
        LIBNAME CICSTRAN COMPRESS=YES;                                  
        %INCLUDE SOURCLIB(BUILDPDB);                                    
                                                                        
     The last choice, writing the CICSTRAN and DB2ACCT datasets to TAPE 
     LIBNAMEs, compressing only the output PDB library, increased the   
     CPU time from minimum by only 3 minutes, to 34, with only 8750 cyl 
     required for the uncompressed WORK and compressed PDB libraries.   
                                                                        
     Note that for TAPE output on z/OS, again, it all depends!!         
     With the Global COMPRESS=YES option, TAPE output is NOT COMPRESSED;
     this makes complete sense, since ALL tape control units compress at
     that hardware level, at NO CPU cost.  However, if COMPRESSS=YES    
     is specified either as a dataset option or as a LIBNAME option, SAS
     does compress tape output datasets.   This could be required if you
     have virtual tape systems that write uncompressed to DASD.         
                                                                        
     Additionally, compression of datasets in a libref are always at    
     the dataset level.  For example, if you use COMPRESS=YES option on 
     a LIBNAME, all created datasets will be compressed, but you could, 
     later, add an uncompressed dataset to that data library.           
                                                                        
     So, my recommendation for z/OS is to still use the MXG default of  
     Global COMPRESS=YES.  I think the exposure and cost of running out 
     of disk space, causing a BUILDPDB job to ABEND, is far higher than 
     the small increase in CPU time, especially if the BUILDPDB is run  
     in the slack time of day.  But, the above tests do quantify the    
     possible CPU time savings, if that truly is the limiting factor.   
                                                                        
 2.  Removal of duplicate observations from MXG's PDB.JOBS.             
                                                                        
   A "job" is a unique instance of READTIME JOB JESNR, but a PDB.JOBS   
   observation is created from multiple SMF type 6, 26 and 30 records   
   which might be created in several days' SMF datasets.                
                                                                        
  -There are several sources of possible duplicates in PDB.JOBS:        
                                                                        
   a. Duplicate records have NEVER been created in the VSAM SMF dataset,
      but design errors in the SMF VSAM dumping procedures, human errors
      or hardware or software failures in the SMF processing jobstream  
      have created actual duplicate records in the SMF datasets that MXG
      processes.  If you have a well designed SMF dumping procedure,    
      and never experience a job failure, you cannot have duplicates.   
                                                                        
   b. If duplicated SMF records do exist in the input SMF file that MXG 
      reads (e.g., same SMF dataset concatenated to itself), BUILDPDB   
      will NOT create duplicates in PDB.JOBS, because the NODUPRECS SORT
      option is used to remove duplicates from the datasets MXG creates 
      in the BUILDPDB program.  These sorts require BY lists that span  
      all possible sequences so that duplicates are physically adjacent,
      and that is why sometimes, the MXG BY list has had to be changed  
      to guarantee that adjacency for duplicate removal.                
                                                                        
   c. But "pseudo-duplicates" can be created by BUILDPDB that we do NOT 
      want to remove: PDB.JOBS observations with the same READTIME JOB  
      and JESNR, but that are not actual duplicates.  The SPINCNT value 
      in IMACSPIN sets the number of BUILDPDB executions (days) when    
      records for inflight (incomplete) jobs are held; jobs are "spun"  
      until the job's Purge record is read.  When SPINCNT is exceeded,  
      whatever records happen to be in that SPIN library will be output 
      to that PDB.JOBS.  Then, when more of that job's records are read,
      another observation with the same READTIME JOB JESNR is output, in
      a different day's PDB.JOBS.  But these are not duplicates; each   
      will have different sets of variables populated from the different
      SMF records that were read.  For example, if SPINCNT=0, a job that
      executed today, but was in the held output queue when SMF VSAM was
      dumped, will create a PDB.JOBS observation with the CPU/EXCP/etc  
      execution resource variables populated, but all of the scheduling 
      datetimes (JSTRTIME,JPURTIME,etc) from the Purge record will have 
      missing values.  Then, tomorrow, when the print/purge SMF records 
      are read, a second observation for that job will be output with   
      that same READTIME JOB JESNR, but with only the print lines and   
      scheduling datetime variables populated.  We do NOT want to delete
      these pseudo-duplicate observations from our PDB.JOBS dataset.    
                                                                        
   d. But "real" duplicate observations can be created, if              
      SMF records that were read "yesterday" are accidentally reread    
      again "today".  This would create separate PDB.JOBS observations  
      in two different daily PDBs that WOULD have identical values for  
      all resources.  Those duplicate observations differ ONLY in their 
      ZDATE/ZTIME values (the "run date" of the BUILDPDB execution), so 
      if you do then combine the daily PDBs into the same WEEKs PDB,    
      you CAN use this PROC SORT to delete these true duplicates.       
                                                                        
         PROC SORT NODUPKEY DATA=WEEK.JOBS OUT=WEEK.NODUPJOB;           
           BY READTIME JOB JESNR INBITS JINITIME JTRMTIME INITTIME      
           PRINTIME JPURTIME CPUTM EXCPTOTL EXCPTODD EXCPNODD PRINTLNE; 
                                                                        
      Option NODUPKEY must be used here, instead of MXG's normal NODUP, 
      because ZDATE/ZTIME are NOT identical in each pair of duplicates. 
                                                                        
   e. BUT: if only some of the job's records are repeated, or if the job
      already is "SPINing" (has some records held in the SPIN library), 
      then the re-reading of only some of a job's SMF records is much   
      more insidious, and the above PROC SORT would not likely detect   
      that kind of duplication.                                         
                                                                        
 1.  Search Arguments.                                                  
                                                                        
     Some examples of search arguments for MXG and related information: 
                                                                        
     Using Google to keyword search at a specific site, for example, at 
     www.mxg.com or at www.ibm.com:                                     
                                                                        
       +websphere +db2 +wlm +classification site:mxg.com                
                                                                        
       +websphere +db2 +wlm +classification site:ibm.com                
                                                                        
     Alternatively, this url is the Google Advanced Search page:        
                                                                        
       http://www.google.com/advanced_search?q=site:www.mxg.com&hl=en   
                                                                        
     For mxg.com, you can also use the SITE SEARCH option (on left) at  
                                                                        
       http://www.mxg.com/newsletters/                                  
                                                                        
     But the MXG-L ListServer Postings Archive is not at www.mxg.com,   
     so the above site searches will not find MXG-L postings.  The link 
     to search all MXG-L postings, since its Oct, 1996, inception, is:  
                                                                        
       http://peach.ease.lsoft.com/scripts/wa.exe?A0=MXG-L              
                                                                        
                                                                        
III. MVS, a/k/a z/OS, Technical Notes.                                  
                                                                        
13. APAR OA30974 reports that if you use SMF Logger AND have removed all
    MANx datasets from SMFPRmxx, but have LASTDS(HALT) specified there, 
    an IPL will fail, as it enters a WAIT DOD RSN01 wait state.  Remove 
    the LASTDS(HALT) to circumvent until IBM has a PTF for the APAR.    
                                                                        
12. APAR OA31547 reports that SMF 89 records can stop being written if  
    they change SMF recording from NOACTIVE to ACTIVE. APAR Still Open. 
                                                                        
11. APAR PK86020 reports A REPORTING PROBLEM WITH THE RMF WORKLOAD      
    ACTIVITY REPORT WITH RESPECT TO THE TRANS-TIME                      
    ERROR DESCRIPTION:                                                  
    A reporting problem with the RMF Workload Activity report with      
    respect to the Trans-Time.  Here is a sample report that shows the  
    TRANS-TIME values that are not correct:                             
        TRANS-TIME HHH.MM.SS.TTT                                        
        ACTUAL               973                                        
        EXECUTION            875                                        
         QUEUED               97                                        
    USERS AFFECTED:  All users of IBM WebSphere Application             
                     Server V6.1.0 viewing RMF diagnostic               
                     reports.                                           
    The RMF Workload Activity report shows an incorrect queued          
    value under the TRANS-TIME values.                                  
    PROBLEM CONCLUSION:                                                 
    Because the queue times are reported based on the values in the     
    thread at the time of capture, the values presented may be incorrect
    if the thread has switched during the course of processing.  This   
    may occur if SSL or webservices are active.  The problem is resolved
    by copying these values through the java portion to circumvent the  
    loss of the values during thread switching.                         
    APAR PK86020 is currently targeted for inclusion in Service Level   
    (Fix Pack) 6.1.0.29 of WebSphere Application Server V6.1            
                                                                        
10. APAR OA31088 reports Z/OS 1.11 B10 INCORRECT FREE SPACE AND LARGEST 
    FREE EXTENT IN SMS VOLUME CONTROL BLOCK IMMEDIATELY AFTER VARY      
    ONLINE                                                              
    ERROR DESCRIPTION:                                                  
    In z/OS 1.11 environment, free space and largest free extent are    
    incorrect for new volumes that have been varied online and have not 
    had any datasets allocated to it.  The incorrect statistics are in  
    the volume statistics control block (IGDVLD) which feeds downstream 
    systems such as RMF.  Beginning in Z/OS 1.11, an additional call is 
    now being made such that the volume statistics will be updated when 
    the volume is varied online eliminating the need to allocate a small
    1 trk dataset to the volume (APAR OA23901 included in 1.11 base).   
    This client saw incorrect RMF Storage Group and volume statistics   
    Additional symptom:                                                 
    ISMF LISTSYS statistics are incorrect after the vary.               
    ISMF LISTVOL command statistics seem to be correct.                 
    LOCAL FIX:                                                          
    Allocate a dataset to the volume which will update the free space   
    and largest free extent statistics correctly.                       
                                                                        
 9. APAR OA30299 reports SMF74DCI SMF74DCT BLANK FOR DEVICE FOLLOWING   
    HIPERSWAP                                                           
    After a hyperswap or DDR device swap, IOS will issue an ENF 28 DDR  
    and ENF 23 Device Online for the target device of the swap.  Both   
    ENFs are processed by RMF listen exit module ERBMFEAR.  But RMF     
    module ERBMFIDA, which updates the DDB, is only called when         
    processing the ENF 23 for device online event.  Since ENF 28 DDR    
    runs asynchronously, it can happen that the ENF 28 is processed     
    before ENF23 so that the call to ERBMFIDA is skipped. As result of  
    this the RMF DDB is not updated.  Affected RMF releases: z/OS-1.9 up
    to and z/OS-1.11                                                    
    PROBLEM CONCLUSION: With this APAR, the ENF 28 listen exit handler  
    in module ERBMFEAR is changed to call ERBMFIDA when the             
    configuration token in EDDDB field EDDDSDCT is blank.               
                                                                        
 8. APAR OA31471 reports variable SMF75AVU, MXG variable AVGUSED,       
    the average number of used slots in the RMF PP PAGESP report is too 
    low. The problem occurs when large page datasets are used and RMF   
    Monitor I zz data gatherer session runs with a very small cycle time
    (e.g. 100 ms).                                                      
                                                                        
 7. APAR OA30633 reports HIGH CPU IN GRS WHEN ZFS QUERYING FILE SYSTEM  
    OWNER FOR RMFGAT DATA GATHERING.                                    
    When running with RMFGAT data gathering option "ZFS", RMF makes     
    requests to zFS to collect statistics on zFS file systems.  As a    
    result, zFS makes ISGQUERY requests to GRS to determine the owner of
    each file system.  The GRS GQSCAN routine scans for enqueues across 
    the sysplex and can be CPU intensive.  LOCAL FIX:                   
    BYPASS/CIRCUMVENTION: The collection of ZFS data can be turned off  
    by specifying Monitor III data gatherer option "NOZFS".             
                                                                        
 6.  APAR OS30551 reports zeros for buffer statistics above 2GB until   
     buffer utilization exceeds 80%.  APAR OA27343 created the error.   
     APAR OA72343 was installed.                                        
                                                                        
 5.  Daylight Savings Time and CMF and GMT Offset.                      
                                                                        
     With BMC's CMF monitor instead of RMF, you must bounce the MVSPAS  
     (CMF) Address Space after the CEC Clocks were reset for DST Fall   
     Back of the clocks.  If the STCs were not bounced, the values in   
     the CMF fields that MXG INPUTs as GMTOFFTM and GMTOFF72 continued  
     to remain the offset prior to the Fall Back. The incorrect GMTOFF72
     did not cause incorrect timestamps in the TYPE72GO dataset, but the
     incorrect GMTOFFTM variable apparently caused datasets ASUM70PR &  
     ASUM70LP timestamps to correspond to the incorrect GMT offset.     
     The wrong GMT Offset will continue to be in your RMF SMF records   
     until the CMF Address Space is restarted.                          
                                                                        
                                                                        
 4.  Comparison of Seconds of CPUTM in PDB.TYPE72GO and PDB.SMFINTRV,   
     shows RMF and SMF interval data match very well.                   
                                                                        
           Startime     SYS1    SYS2    SYS3   SYS4     Total           
                                                                        
                                                                        
     SMF   05NOV09:00   4350     671    2641    212      7876           
     RMF   05NOV09:00   4339     665    2751    217      7974  +  96    
                                                                        
     SMF   05NOV09:01   3696     670    1473    201      6041           
     RMF   05NOV09:01   3802     678    1330    206      6016  -  25    
                                                                        
     SMF   05NOV09:02   5044     753    3041    204      9043           
     RMF   05NOV09:02   5050     761    3012    211      9036  -   7    
                                                                        
     SMF   05NOV09:03   7527     836    4359    213     12936           
     RMF   05NOV09:03   7507     856    4369    268     13002  +  66    
                                                                        
     SMF   05NOV09:04   4465     851    4411    278     10006           
     RMF   05NOV09:04   4752     868    4522    237     10380  + 374    
                                                                        
                                                                        
 3.  An interesting post on IBM-MAIN by John Eells, IBM z/OS Technical  
     Marketing, on what IBM can/can't do when a change is introduced:   
     We can't win on the default.  We can only pick which group of      
     customers to annoy:                                                
     - If we default a behavioral change we introduce a migration       
       action. Customers overwhelmingly tell us they hate migration     
       actions. "Look at this behavioral change, see if you care, and   
       change something if you don't want it to happen" is a migration  
       action.                                                          
     - If we don't default the behavioral change, people who want it    
       tell us that "everyone" would want it to be the default.         
      We have historically been poor predictors of which group will be  
      larger, so we are "defaulting" more and more to avoiding          
      behavioral changes that "just happen."                            
                                                                        
 2.  APAR OA30246 reports that XRC zIIP-eligible-work in Service Class  
     SYSTEM is not dispatched on a zIIP, but executes on the CP engines 
     when HiperDispatch is Enabled.  Pending a PTF, the APAR recommends 
     that zip-eligible work be moved to Service Class SYSSTC, or to     
     disable HiperDispatch.                                             
                                                                        
 1. Summary: "EXCP" counts recorded for access to HFS & ZFS filesystems:
                                                                        
    An  HFS file, 10,000 50-byte records, 496K, or 123 4096-byte blocks,
    & a ZFS file,  1,000 50-byte records,  49K, or  13 4096-byte blocks,
    was created/copied on z/OS 1.9 by different programs.               
     Total "EXCP"s were between 50 and 23,710 for HFS.                  
     Total "EXCP"s were between 37 and  5,416 for ZFS                   
                                                                        
     These "EXCP" counts are displayed on JOBLOG and are included in the
     SMF 30 Address Space Total EXCP count, EXCPTOTL (SMF30TEP).        
                                                                        
                                         HFS               ZFS          
                                        496K               49K          
         Job Description                EXCPTOTL         EXCPTOTL       
                                                                        
     TEST92LD -SAS92 LOAD             23710,23290         5416          
     TEST91LD -SAS91 LOAD             21856,21785         3867          
     TEST92RD -SAS92 READ             13364,13295         4464          
     TEST91RD -SAS91 READ             11787,11763         2891          
     TESTGENR -IEBGENER READ            309,  306          n/a          
     TESTFAST -FASTGENR READ            298,  285           65          
     TESTSORT -SYNCSORT READ            209,  209           70          
     TZOS92LD -SAS92 LOAD z/OS         3301               3324          
     TZOS91LD -SAS91 LOAD z/OS         1764               1771          
     TSTWGENR -IEBGENER WRITE           301                n/a          
     TSTWFAST -FASTGENR WRITE           268                 53          
     TSTWSORT -SYNCSORT WRITE           252                 62          
     ZOSCGENR -IEBGENER COPY            113                 53          
     ZOSCFAST -FASTGENR COPY             50                 28          
     ZOSCSORT -SYNCSORT COPY             46                 37          
                                                                        
                                                                        
All of the SMF records written for two of these test jobs were analyzed 
in detail: the SAS-TEST91LD and FASTGENR-TESTFAST are analyzed in       
detail below; the other job's SMF data will                             
                                                                        
SAS was used to create a 10,000 record text file of 50 byte records,    
 written to an dynamically allocated HFS1 Filename.                     
                                                                        
FASTGENR was then used to copy that hfs file, with a static SYSUT1 DD,  
 to a disk data set.                                                    
                                                                        
A. EXCP counts in DD Segments in SMF type 30 subtype 2, 3, 4, and 5):   
                                                                        
 1. There was no DD segment created segment for the dynamically         
      allocated HFS1 DDNAME in the SAS job.                             
                                                                        
 2. While there was a SYSUT1 DDNAME in the type 30 records for the      
      FASTGENR job, it contained ONLY the DDNAME; there were no EXCPs   
      recorded, and there was no DEVNR nor DEVCLASS/DEVTYPE information.
                                                                        
B. EXCP counts in the address space fields in the SMF 30 record:        
                                                                        
 1. HFS "EXCP" counts ARE captured in the SMF 30 record; but only in    
      in the address space total EXCP Count EXCPTOTL(SMF30TEP/TEX).     
    - RMFEXCP are the EXCPs counted in IO Service Units (SMF30IO/IOL),  
      and the HFS EXCP count IS included in RMF IO Service Units.       
    - EXCPTODD is the sum of all EXCPs in the DD segments.              
    - EXCPNODD is the EXCPs count NOT counted in the DD segments,       
      calculated as EXCPTOTL minus EXCPTODD.                            
    - EXCPDASD is the total DD EXCPs count to DASD devices.             
    - SMF30AIS is the total count of DASD SSCH's (NOT BLOCKS/EXCPs)     
    - IOTM variables are the IO Connect Time durations, as above.       
                                                                        
       JOB         EXCPTOTL RMFEXCP  EXCPTODD  EXCPNODD EXCDASD SMF30AIS
                                                                        
       SAS           21785   21778     1379     20406     1379    704   
       FASTGENR        285     280      101       184      101    213   
                                                                        
       JOB         IOTMTOTL RMFIOTM  IOTMTODD  IOTMNODD                 
       SAS           0.51     n/a      0.37      0.14                   
       FASTGENR      0.02     n/a      0.02      0.01                   
                                                                        
   Observations:                                                        
                                                                        
   a. SAS wrote 10,000 blocks of 50 bytes each, but counted 20,000 EXCP,
      and that count was also shown on the SAS log; why 20000 was the   
      count will be investigated with their HFS guy when he is back from
      vacation, but that count of 20000 was passed to IEASMFEX, as it   
      does show up in the EXCPTOTL and RMFEXCP.                         
                                                                        
   b. FASTGENR, the SYNCSORT replacement for IEBGENER, counted 101      
      "EXCP"s to the 3390 output disk device in the EXCP segment for    
      SYSUT2; the "EXCP"s reading the HFS file were counted as 184 in   
      the EXCPNODD (i.e., included in EXCPTOTL and RMFEXCP).            
      But FASTGENR and SYNCSORT have NEVER counted EXCPs, but, instead  
      count SSCHs, and that is what it passed to IEASMFEX.              
        (I was involved in legal issues between DFSORT and SYNCSORT     
         because SYNCSORT published false I/O comparisons that used the 
         SIOs for SYNCSORT but BLOCKS/EXCPs for DFSORT, many years ago. 
         There was a "Special Core Zap" from SYNCSORT that would change 
         their count to BLOCKS, but I don't know if it still exists, and
         I suspect no one uses is now!).                                
      In addition, the FASTGENR log shows that it read and wrote        
      10,000 logical records; however it shows a total size of          
      800,000 bytes, whereas only 500,000 bytes were written, so        
      even FASTGENR can't correctly count HFS activity.                 
                                                                        
   c. While HFS EXCP counts are in the EXCPNODD field, there are other  
      I/O counts included in EXCPNODD, for all file I/O that does not   
      have a DD:  Catalog I/O, LinkList I/O, and JES2 SPOOL I/O, and the
      JES2 Spool I/O count can be significant.                          
                                                                        
C. HFS-only EXCP counts do exist in the OMVS Segment of type 30s.       
                                                                        
   The old "OMVS" segment is now known as                               
   "z/OS UNIX System Services Process Section" in the SMF manual.       
                                                                        
   I LOVE the fact that UNIX is in CAPITAL LETTERS!                     
                                                                        
   MXG's first technical note on measuring unix, by Chuck Hopf,         
   was subtitled "or how i learned to type in lower case".              
                                                                        
  1. The SAS job created one "OMVS" segment, while the FASTGENR created 
      two segments, having apparently spawned/forked/whatever unix does 
      that created a second PID for their copy program.  The first three
      columns are the only block count fields that were non-zero; the   
      last columns are the only other metrics that were non-zero.       
                                                                        
                DIR     DATA    DATA        PATHNAME  PATHNAME SYSCALLS 
                READ    READ    WRITE       LOOKCALL  LOOKCALL REQUESTED
       JOB      BLOCKS  BLOCKS  BLOCKS      LOGICAL   PHYSICAL BY       
                                            FILES     FILES    PROCESS  
                                                                        
                OMVSODR OMVSOFR OMVSOFW     OMVSOLL   OMVSOLP   OMVSOSC 
                                                                        
      SAS          65       0    20000          8       37       21     
                                                                        
      FASTGENR-1   16       0        0          2        8        3     
      FASTGENR-2   26     125        0          3       13        4     
                                                                        
      FASTGENR     42     125        0          5       21        7     
                                                                        
      Comparing the type 30 with the type 30 OMVS segment:              
                                                                        
                   Total I/O Blocks OMVS   Total NODD IO COUNT          
      SAS                20065                  20406                   
      FASTGENR             167                    184                   
                                                                        
   Observations:                                                        
                                                                        
   a. The UNIX segment EXCP counts can indeed be subtracted from the    
      address space EXCP counts, for sites that do NOT want to include  
      HFS EXCPs in their billing, if they are using the EXCPTOTL field. 
                                                                        
   b. I polled MXG users, and most said that when EXCP counts were used 
      in chargeback, they used only the EXCPDASD and EXCPTAPE counts    
      (MXG sums DD EXCP counts by device type); the use of EXCPTOTL that
      includes HFS (and SPOOL) counts are not commonly used in billing. 
                                                                        
                                                                        
D. HFS-only EXCP counts do exist in the Type 92 records.                
                                                                        
   The jobs each created one subtype 10 and one subtype 11; only the 11 
   has resource metrics:                                                
                                                                        
         BYTES    BYTES    DIR I/O  DATA I/O DATA I/O READCALL WRITECALL
         READ     WRITTEN  BLOCKS   BLOCKS   BLOCKS   ISSUED   ISSUED   
                           RD/WR    READ     WRITTEN                    
         SMF92CBR SMF92CBW SMF92CDI SMF92CIR SMF92CIW SMF92CSR SMF92CSW 
                                                                        
  SAS:       0      498K      12        0     20000       0     20000   
  SYNC:    498K       0       10      125         0       9         0   
                                                                        
  Observations:                                                         
                                                                        
  a. While FASTGENR reported 800,000 bytes copied, the SMF 92 shows that
     FASTGENR is wrong (it used a default LRECL=80 times 10,000 logical 
     records), and that SAS was right (it showed 10,000 logical records 
     with the correct 50 byte LRECL).                                   
                                                                        
  b. The EXCP counts for HFS activity, 20012 for SAS and 135 for SYNC   
     in the SMF 92 are consistent with the counts in the OMVS segment   
     and the EXCP counts passed into the type 30 step records, but      
     the values are the counts passed by the application, blocks for    
     SAS, and SSCH for FASTGENR, and there's no way to tell which is    
     which.                                                             
                                                                        
E. No SMF 42 subtype 6 records were created for hfs for these jobs.     
                                                                        
   And I did NOT expect to see those records, as they are documented in 
   the SMF manual "records DASD data set level I/O statistics", and, for
   these two jobs, hfs was NOT a DASD data set.                         
                                                                        
   There were type 42 subtype 6 records created for the DASD DDnames for
   the two jobs, and they captured these counts, for comparison with the
   SMF 30s:                                                             
                                                                        
   JOB      TOTAL NUMBER CACHE       Sequential  Read        Sequential 
   TOTAL    OF IOS       CANDIDATES  blocks      Operations  I/O's      
            IOCOUNT                  read        to Dataset             
            (S42DSION)   (S42DSCND)  (S42aMSRB)  (S42DSRDT)  (S42DSSEQ) 
                                                                        
   SAS         442         187          27        431            5      
   FASTGENR    101           1                      1          100      
                                                                        
  Observations                                                          
                                                                        
  a. Whereas the EXCP counts in the TYPE 30 are whatever the application
     access method passed to SMF, type 42 subtype 6 counts are direct   
     from the hardware, independent of the access method, etc.          
  b. The FASTGENR SSCH count of 101 SSCHs in the type 42 is the same as 
     the SSCH count passed by FASTGENR into the SYSUT2 DD segment, and  
     that was the only DD allocated to DASD, since SYSUT1 points to the 
     hfs file.  But the (relatively new) SMF30AIS field, documented as  
     "DASD I/O Start Subchannel Count for address space and dependent   
     enclaves" count of 213 appears to me to be in error.               
     The SAS EXCPDASD count of 1379 is consistent with SMF30AIS of 704, 
     as half-track blocking is normally used by SAS.                    
  c. I believe there would be type 42 subtype 6 records created for the 
     z/OS VSAM file that "contains" the HFS file system, but those data 
     would have the JOB name of the address space from which the actual 
     physical I/O occurs, and those counts would be for all users of the
     file system, with no counts for the actual jobs that cause the I/O.
                                                                        
F. Data on the banner page may include HFS counts in the "EXCP Count"   
                                                                        
   This site uses the IBM "banner page" to print EXCP counts on Job Log;
   the EXCP count that is printed is, indeed, that EXCPTOTL/SMF30TEP    
   Address Space Total Count, and which we now know DOES include the HFS
   "EXCP"s, and those counts are only slightly larger than the two      
   products reported on their execution logs:                           
                                                                        
                   Banner        Product                                
                   Page          Log's                                  
                   EXCPs         EXCPs                                  
    SAS            21785         20240                                  
    FASTGENR         285           240                                  
                                                                        
   Observation:                                                         
                                                                        
   a. This is very likely the source of the large EXCP counts that have 
      been reported, since it requires no analysis of the SMF 30 records
      (and I think this is also the EXCP count displayed by SDSF).      
                                                                        
G. Conclusions                                                          
                                                                        
   1. Whatever is counted by the application as an "EXCP" for HFS access
      whether blocks or SSCHs (at the whim of the I/O programmer!) is   
      included in the EXCPTOTL field in the SMF 30 records, and is the  
      count that is displayed by banner pages and SDSF.                 
                                                                        
   2. The type 30 OMVS segments are now used in MXG 27.08 Change 27.213,
      to create the new USSEXCPS count variable that could be used to   
      "back-out" these large counts, if the site is actually using the  
      EXCPTOTL field in chargeback and has significant USS activity.    
      See MXG Newsletter FIFTY-FIVE, MXG Technical Note titled          
       1. Summary: "EXCP" counts recorded for access to HFS & ZFS ....  
       HFS "EXCP" counts ARE captured in the SMF 30 record, BUT....     
                                                                        
   3. With the inaccuracies in counting HFS and zFS EXCPs, and because  
      they are included in the RMF IO Service Units,  alternative ways  
      to count, including dividing the total bytes in the 92s by 4096   
      are under consideration by IBM.  This research is in progress and 
      this note will be updated is corrections are made.                
                                                                        
IV.   DB2 Technical Notes.                                              
                                                                        
 1.  X                                                                  
                                                                        
V.   IMS Technical Notes.                                               
                                                                        
 1.  X                                                                  
                                                                        
VI.  SAS Technical Notes.                                               
                                                                        
  9. SAS Note 32778 reports ABEND 413 Return Code 18 (413-18) can occur 
     with SAS V9.2, if you create a new library on tape, when the new   
     tape dataset is allocated in Job Control.  For example, this JCL   
     can cause this ABEND:                                              
                                                                        
      //CICSTRAN DD DSN=TAPE.CICSTRAN,DISP=(NEW,CATLG,DELETE),          
      //       UNIT=3590-1                                              
                                                                        
     The error message that results will be similar to the following:   
                                                                        
     IEC145I 413-18,IFG0194A,TAPEDD,V921M0,CICSTRAN,0470,,TAPE.CICSTRAN 
                                                                        
     The following error messages might also appear in the SAS log:     
                                                                        
      ERROR: OPEN of CICSTRAN failed. Abend code 413. Return code 18.   
      ERROR: An I/O error has occurred on file CICSTRAN.                
                                                                        
     To circumvent this problem, explicitly name the engine with which  
     the library should be assigned, as in the following example:       
                                                                        
       //SYSIN DD *                                                     
       LIBNAME CICSTRAN V9SEQ;                                          
                                                                        
  8. Exposure on Windows to FAIL/ABEND with LOCK NOT AVAILABLE ERROR.   
                                                                        
     SAS Technical Support confirms that execution of SAS under Windows 
     has ALWAYS been exposed to a LOCK NOT AVAILABLE error because any  
     file's lock can be "grabbed" by another process at any time, even  
     a SAS dataset file in the WORK data library!  MXG creates a dataset
     WORK.ZZdddddd with PROC SORT, reads it with SET ZZdddddd and then  
     PROC DELETE DATA=ZZdddddd.  But in several QA runs under Windows 7,
     SAS lost its file lock after the DATA step closed successfully,    
     causing the PROC DELETE to fail, terminating the QA job:           
       -"Lock held by another process" is probably caused by a backup   
        program, antivirus program, encryption, or an indexing          
        application like Google Desktop that is accessing or touching   
        the SAS temporary files while they are in use by SAS.  If a     
        backup program or virus scan is running on an interval, that    
        would explain why the problem is intermittent.                  
       -To fix the lock, add the file extensions used by SAS to the     
        exclude list of the interfering application; you should exclude 
          .lck , .sd2,  .sc2 , .SPDS, and .Sas*                         
        where the .SAS* wild card excludes these extensions:            
          .sas7bdat /* DATA */     .sas7bfdb /* FDB */                  
          .sas7butl /* UTILITY */  .sas7bitm /* ITEMSTOR */             
          .sas7bput /* PUTILITY */ .sas7baud /* AUDIT */                
          .sas7bcat /* CATALOG */  .sas7bbak /* BACKUP */               
          .sas7bpgm /* PROGRAM */  .sas7bdmd /* DMDB */                 
          .sas7bndx /* INDEX */    .sas7bods /* SASODS */               
          .sas7bvew /* VIEW */     .sas /* SAS program file */          
          .sas7bacs /* ACCESS */                                        
          .sas7bmdb /* MDDB */                                          
        Caution: careful when excluding non-temporary SAS data sets from
        a backup.  SAS Recommends that backups occur when SAS is not    
        running.                                                        
        Caution two: other applications can use those suffixes:         
            SC2 - windows scheduler                                     
            SD2 - sound designer                                        
            LCK - database control                                      
            SPDS - ACROBAT                                              
       -If the problem application is not a backup program or virus scan
        then the cause is still probably a third party program. A way to
        determine which program(s) are causing the lock is to use       
        utility from Microsoft Sysinternals called Process Monitor. You 
        can download Process Monitor for free from Microsoft at         
                                                                        
          http://technet.microsoft.com/en-us/sysinternals/              
                    bb896645.aspx?PHPSESSID=d926                        
                                                                        
          Open Process Monitor, click filter and make these 3 changes:  
            1)Path "begins with" "%temp%\SAS Temporary Files"           
              (Click ADD) (use your work path name, if different).      
            2)Process Name is Sas.exe then Exclude (click Add)          
            3)Process Name is Explorer.exe then Exclude (click Add)     
            Click Apply and OK.                                         
                                                                        
          Then clear the log.                                           
                                                                        
          Then start SAS and run the SAS program that creates the lock  
          error. What Process Name(s) are listed in Process Monitor?    
                                                                        
          This particular filter doesn't always find the problem.       
          Usually the best advice is to ask your internal support team  
          for help using this tool to find the problem                  
                                                                        
     We have not yet been able to identify what process grabbed the file
     lock, because the lock conflict is intermittent.                   
                                                                        
     BUT: The pathname of the WORK data library was NOT the SAS default:
          it did NOT contain the text "TEMP" nor "SAS Temporary"        
     We have changed that pathname to the SAS default, and there has not
     (YET!) been a lock conflict, so we presume/assume that the process 
     causing the conflict automatically excluded scanning of directories
     with "TEMP" in their name.                                         
                                                                        
  7. SAS USER U1319 ABEND if EXITCICS/CICSIFUE and /VIEW=_WCICTRN used, 
     OR WITHOUT SAS HOT FIX 37166 for SAS 9.1.3 SP4.  Fixed in SAS 9.2. 
                                                                        
     Using a VIEW for CICSTRAN with the CICSIFUE decompression INFILE   
     user exit caused a USER ABEND U1319 error, that is now corrected in
     the SAS HotFix for SAS Note 37166.                                 
                                                                        
     This SYSIN input caused the U1319 abend :                          
                                                                        
        %LET SMFEXIT=CICS;                                              
        %INCLUDE SOURCLIB(VMACSMF,VMAC110,VMXGUOW,IMACKEEP);            
        DATA                                                            
        _VAR110                                                         
          /VIEW=_WCICTRN;                                               
        _SMF                                                            
        _CDE110                                                         
        _S110                                                           
                                                                        
     with these cryptic messages on the SAS log:                        
                                                                        
        +No MKLEs found                                                 
        +ERROR: VM 1319: The PCE address= 1848CB54                      
                         and MEMORY address=000D98D8                    
        IEA995I SYMPTOM DUMP OUTPUT  749                                
        USER COMPLETION CODE=1319                                       
                                                                        
     Removing /VIEW=_WCICTRN, the execution works fine with the Exit.   
     Also using TYPS110 worked fine (because it doesn't have a /VIEW).  
                                                                        
     But the same error message will occur with BUILDPDB due to the view
     for VMACID.  This error can be circumvented by inserting this      
     statement in your //SYSIN                                          
         %LET VWVMACID=;                                                
     which disables that sole VIEW in the BUILDPDB.                     
                                                                        
     Change 27.260 is a VERY-EXPENSIVE-ON-Z/OS-alternative to EXITCICS. 
                                                                        
  6. You can NOT concatenate DSNAMEs behind //LIBRARY DD on z/OS; the   
     job will die with a 0C4 ABEND, as documented in SAS Note 12807 or  
     SAS Note 16096. The SYSMSG shows these z/OS messages:              
       IGD103I SMS ALLOCATED TO DDNAME LIBRARY                          
       IGD103I SMS ALLOCATED TO DDNAME                                  
       And subsequently we see this:                                    
       IGD104I SYSDPCP.SL9.BILLPROJ.LBL4MATS RETAINED,DDNAME=SYS00004   
       IEC131I 1,MXGDAY,MXGSASV9,RDJFCB ISSUED FOR DCB WITH BLANK DDNAME
     And the SAS log has this error message:                            
     +ERROR: SYSTEM ABEND00C4 OCCURRED IN MODULE SASVC FUNCTION VVCLCHK.
                                                                        
  5. The use of WHERE ALSO statement and OPEN=DEFER with a SET statement
     with multiple datasets does not work as expected; while the WHERE  
     and WHERE ALSO are applied to the first dataset in the SET, only   
     the WHERE expression is applied to all other datasets in the SET   
     statement.  Removing OPEN=DEFER causes the WHERE ALSO to be used   
     for all data sets, or, if OPEN=DEFER is required (when datasets    
     in the SET statement are on tape), then the WHERE and WHERE ALSO   
     expressions must be combined (with an AND) into a single WHERE.    
                                                                        
  4. SYSTEM COMPLETION CODE=EC6 REASON CODE=0000FD1D is actually a USS  
     ABEND, because SAS 9 is now a thread running as a USS process,     
     but that REASON is the old SYSTEM 322 ABEND, CPU Time Exceeded.    
                                                                        
     It can be a little cumbersome finding the appropriate doc for the  
     particular failure. However, for the FD* reason codes on the SEC6  
     abend here is what is documented:                                  
                                                                        
     FDxx                                                               
     If xx is in the range of X'01' to X'7F', a signal was received     
     causing termination and a dump to be taken.  This condition is     
     usually the result of an application programming exception. For a  
     description of the signal represented by the value xx, check the   
     appropriate appendix "BPXYSIGH - Signal Constants" or "Signal      
     Defaults" in z/OS UNIX System Services Programming: Assembler      
     Callable Services Reference.                                       
                                                                        
     In that referenced document, not very pleasant to read, the FD is  
     fixed, and the 1D is the signal constant in Hex. The doc shows the 
     decimal. So convert x'1d' to decimal and it is 29.  For 29 we see: 
                                                                        
     SIGXCPU#   EQU  29   CPU time limit exceeded                       
                                                                        
     SAS 9 with the threading is the cause of these new USS type ABENDS,
     rather than what we are accustomed to.  So when executing within a 
     thread and a failure such as the CPU timeout occurs it will surface
     the SEC6 system abend code.  From this type of abend code it is the
     REASON CODE which has the information needed to further determine  
     the cause.  While MXG sets OPTION NOTHREADS (See Change 22.207),   
     that simply disables thread enabled PROCs from using threads.  SAS 
     itself is running as a thread; in SAS V9, the entry points were    
     changed from the earlier SASHOST/SASXA1/SASXAL to SAS/SASB/SASLPA, 
     which are the wrapper programs for TK environment, which makes SAS 
     itself run as a thread. Hence the system requirement for an OMVS   
     segment sufficient that the user environment can be "dubbed".      
                                                                        
 3. ERROR: SYSTEM ABEND 0C4 OCCURRED IN MODULE SASXKERN FUNCTION YPCDO2 
    was caused by a back-level DSNAME for the SASMSG file.              
                                                                        
 2.  SAS Hot Fix for SN-35332 is REQUIRED for z/OS 1.10 with SAS V9.1.3,
     because  ERROR: LIBNAME XXXXXXXX IS NOT ASSIGNED  can occur for    
     jobs with a completely valid //XXXXXXXX DD statement.  Jobs that   
     run without error on z/OS 1.9 can fail on z/OS 1.10 using the same 
     JCL and SAS/MXG datasets.  If LIBNAME is LIBRARY, there may also be
     a separate message ERROR: FORMAT MGBYTES COULD NOT BE LOADED.      
                                                                        
     The error has NOT occurred with SAS V9.2.                          
                                                                        
     The error can be circumvented with addition of a LIBNAME statement 
     that explicitly specifies the engine name:   LIBNAME LIBRARY V9  . 
                                                                        
     But, INSTALL the Hot Fix (or, better, INSTALL SAS V9.2), as adding 
     a source statement to PROD Source libraries may not be possible!   
                                                                        
     In z/OS 1.10 IBM increased the internal work area required for its 
     OBTAIN service call to 140 bytes (from 101), but SAS's work area   
     was the old size; OBTAIN in 1.10 validates that now-required size, 
     which caused an OBTAIN failure, which SAS surfaced with the above  
     error message. The LIBNAME with ENGINE circumvention works because 
     SAS doesn't need to issue an OBTAIN when the ENGINE is known.      
                                                                        
     SN-35332 is dated March, 2009, but only one MXG site saw the error,
     and not until September, and only on one of their several z/OS 1.10
     systems!                                                           
                                                                        
 1.  Out of Space conditions running MXG jobs on WINDOWS may need to be 
     examined by issuing DOS DIR commands at various points in the job. 
     You can use                                                        
        systask command "dir d:\*.* >> d:\mxg\dirsize.txt" nowait;run;  
     to APPENDed each execution to the single file dirsize.txt, or      
        systask command "dir d:\*.* > d:\mxg\atstart.txt" nowait;run;   
        systask command "dir d:\*.* > d:\mxg\aftersort.txt" nowait;run; 
     etc to send each dir command to a separately named file.           
                                                                        
    -You can run out of space on an empty volume if Disk Quotas have    
     enabled by your System Administrator.  You can view if quotas      
     are enabled and their size with these steps:                       
      1. Open My Computer.                                              
      2. Right click the volume you want to enable disk quotas and click
         Properties.                                                    
      3. Click the Quota tab.                                           
      4. Click the Enable Quota Management option.                      
      5. To limit the amount of disk space for new users click the Limit
         disk space to option.                                          
      6. Set the appropriate values for the Limit disk space to and the 
         Set warning level to options.                                  
      7. Click OK.                                                      
                                                                        
                                                                        
VI.A.  WPS Technical Notes.                                             
                                                                        
 1.  X                                                                  
                                                                        
VII. CICS Technical Notes.                                              
                                                                        
 1.  CICS Capacity was limited by the single QR TCB.                    
                                                                        
     In the old days, a CICS subsystem's capacity was limited by the    
     amount of CPU TCB time needed for that single QR TCB.              
                                                                        
     Based on my analysis when OTE was brand new, of the CPU time       
     consumed by each of these new CICS TCBs, I planned this post to    
     argue that going to OTE didn't help much, because most of the CICS 
     CPU time was still being spent under the QR TCB.                   
                                                                        
     I could NOT have been more wrong!                                  
                                                                        
     Analyzing new CICS/TS 4.1 Open Beta data from a VERY aggressive OTE
     exploiter site shows (from their SMF 110, subtype 2 Dispatcher     
     Statistics segments, MXG CICDS and CICINTRV datasets):             
                                                                        
     Total TCB CPU in Dispatcher Records  = 13,080 seconds              
     Total TCB CPU in QR TCB              =  2,776 seconds              
     Total TCB CPU in L8 TCB              = 10,298 seconds              
     Total TCB CPU in all other TCBs      =      6 seconds              
                                                                        
     Aha, you say, OTE still doesn't help; the CPU time just moved from 
     the QR TCB to the L8 TCB, so the capacity limit just moved from one
     TCB to the other, right?                                           
                                                                        
     Wrong again.                                                       
                                                                        
     While the QR TCB can attach only a single TCB, these new TCBs can  
     attach multiple TCBs; in fact, the SMF data shows that the L8 TCB  
     attached a maximum of 22 TCBs, each of which is a separate         
     dispatchable unit.                                                 
                                                                        
     So, it REALLY does look like that these multiple OTE TCBs do       
     eliminate the old "one-TCB" CICS capacity limitations, and does    
     indeed spread your CICS time across MANY TCBs.                     
                                                                        
     (Total SRB time in the Dispatcher Records was only 65 seconds.)    
                                                                        
                                                                        
                                                                        
VIII. Windows NT Technical Notes.                                       
                                                                        
 1.  X                                                                  
                                                                        
IX.  z/VM Technical Notes.                                              
                                                                        
 1.  X                                                                  
                                                                        
X.    Email notes.                                                      
                                                                        
 1.                                                                     
                                                                        
                                                                        
                                                                        
XI.   Incompatibilities and Installation of MXG vv.yy.                  
                                                                        
 1. Incompatibilities introduced in MXG 27.yy (since MXG 26.26):        
    See CHANGES.                                                        
                                                                        
 2. Installation and re-installation procedures are described in detail 
    in member INSTALL (separate sections for each platform, z/OS, WIN,  
    or *nix), with examples of common Errors/Warnings messages a new MXG
    user might encounter, and in member JCLINSTT for SAS V9.2 or member 
    JCLINSTW for WPS. INSTALL also shows how to read SMF data on PCs/nix
    using the FTP ACCESS METHOD.                                        
                                                                        
XII.  Online Documentation of MXG Software.                             
                                                                        
    MXG Documentation is now described in member DOCUMENT.              
                                                                        
                                                                        
XIIV. Changes Log                                                       
                                                                        
--------------------------Changes Log---------------------------------  
                                                                        
 You MUST read each Change description to determine if a Change will    
 impact your site. All changes have been made in this MXG Library.      
                                                                        
 Member CHANGES always identifies the actual version and release of     
 MXG Software that is contained in that library.                        
                                                                        
 The CHANGES selection on our homepage at http://www.MXG.com            
 is always the most current information on MXG Software status,         
 and is frequently updated.                                             
                                                                        
 Important changes are also posted to the MXG-L ListServer, which is    
 also described by a selection on the homepage.  Please subscribe.      
                                                                        
 The actual code implementation of some changes in MXG SOURCLIB may be  
 different than described in the change text (which might have printed  
 only the critical part of the correction that need be made by users).  
                                                                        
 Scan each source member named in any impacting change for any comments 
 at the beginning of the member for additional documentation, since the 
 documentation of new datasets, variables, validation status, and notes,
 are often found in comments in the source members.                     
                                                                        
Alphabetical list of important changes after MXG 26.26 now in MXG 27.yy:
                                                                        
  Dataset/                                                              
  Member   Change    Description                                        
                                                                        
  See Member CHANGES or CHANGESS in your MXG Source Library, or         
  on the homepage www.mxg.com.                                          
                                                                        
Inverse chronological list of all Changes:                              
                                                                        
Changes 27.yyy thru 27.001 are contained in member CHANGES.