4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 00101: Critical TSO TIOC Buffer Level Detected

00101: Critical TSO TIOC Buffer Level Detected

FILE              TSO System Activity File
SAS FILE NAME     DETAIL.TSOTSO01
SOURCE LOCATION   sharedprefix.MICS.SOURCE(DYTSOEXC)

SEVERITY          Critical      (SEVERITY='C')
MANAGEMENT AREA   Performance   (MGMTAREA='PERFORMANCE')

PURPOSE      Identifies intervals during which all TSO
             terminals were locked out for input because of a
             buffer shortage.

RATIONALE    When the number of Terminal Input / Output
             Coordinator (TIOC) buffers falls below the
             Reserve Buffer (RESVBUF) value specified in
             SYS1.PARMLIB(IKJPRM00), all terminals are locked
             for input.  This is done to ensure a reserve of
             free buffers for output.  No external warning is
             given for this condition except that TSO users
             may experience long response times.  This
             condition may also be indicated by a higher than
             normal number of OWAIT swaps.  For a discussion
             of the use and meaning of the TIOC parameters,
             see OS/VS2 MVS SYSTEM PROGRAMMING LIBRARY:
             INSTALLATION AND TUNING GUIDE, GC28-0681, Part 3
             System Initialization, Member Name:  IKJPRM00.

DEFINITION   This exception is detected when the number of
             TIOC buffers falls within the range that causes
             terminal input lockup.

EXCEPTION    The SAS statements identifying the exception
STATEMENTS   situation and describing the condition are
             stored in the source member named in SOURCE
             LOCATION and are described below:

************************************************************;
*
** 00101
** CRITICAL TSO TIOC BUFFER LEVEL DETECTED
*;
IF TSOUPTM > 0
 AND (0<=TSOMTIOC AND TSOMTIOC<= tioc-buffers)
 THEN DO;
    EXCCODE='00101'; SEVERITY='C'; MGMTAREA='PERFORMANCE';
    EXCDESC1='CRITICAL TSO TIOC BUFFER LEVEL DETECTED';
    EXCDESC2='MINIMUM TIOC BUFFERS=' || PUT(TSOMTIOC,4.);
    LINK HIT;
END;

THRESHOLD     Modify the value for the number of TIOC
MODIFICATION  buffers, which is critical, according to the
              following conventions:

    tioc-buffer   The number of buffers or less which will
                  cause performance degradation.  A threshold
                  of 50, which would be the RESVBUF value,
                  would appear as:

                     (0<=TSOMTIOC AND TSOMTIOC<= 50)

                  NOTE:  The TIOC buffer number for this
                  exception should be coordinated with
                  exception number 00102, which is the
                  warning level exception.