START r page of GC20-1807-7 As Updated April 1, 1981 by TNL GN25-0829
written to tape. When the buffer is written to tape, it is
written as a class 6 (DASTAP) record under monitor code 02. The MONITOR interval is reset to the default of 60 seconds
whenever any of the following occurs: The user issues MONITOR STOP, automatically
or the monitor stops The system stops the MONITOR because of an unrecoverable I/O error The end of tape or spool record limit is reached
, [To userid] [ BUFFS n] I I r , I ITAPE raddr '1I0DE{BOO }' I I I 1600 I [ BUFFS n] I I I 6250 , I I L .J I ICPTRACE I L .J
starts VM/370 Monitor data collection to the spool file or
tape, or starts the CP internal trace table. If no optional
parameter is provided, SPOOL is the default. KONITOR START SPOOL starts the VM/370 Monitor data collection using a spool
file for storage. When data collection is stopped and the spool is closed, the
spool file is added to the chain of reader files destined for
the virtual reader of the virtual machine defined by "userid." Userid may be an asterisk (*) if the recipient virtual machine
is to be the one from which the START command is issued. If
the TO USERID option is omitted, the userid specified in the SYSMON macro is used (See the VK/37Q The TO USERID option overrides the SYSMON specification and stays in effect until the system is
reinitialized or a new command is issued.
The monitor spool file is closed by a MONITOR STOP or MONITOR CLOSE command, or when the record count limit is reached (as
specified in the SYSMON macro), or when a system restart or
system shutdown occurs.
The filename and filetype is generated internally with the
filetype identifying date and time of starting.
The class of spool file is specified in the SYSMON macro and
defaults to "M". If no classes of data collection have been
specified with an ENABLE command, then those specified with
the SYSMON macro are used.
The number of monitor buffers used are as specified in the SYSMON macro, or as requested with the BUFFS option of the START command. The BUFFS option overrides the SYSMON specification only for the duration of the data collection
session. Future monitoring sessions subsequently return to
-t he - SY SftON-- sp-ec-i-fi-ea-t-io-n---- -u--nl-e-ss- --- -aija i n - o-verr-id-den. I-f - the
number of buffers specified in the SYSKON macro has been
defaulted, then the defaults described in the MONITOR START TAPE command are adopted. Part 2. Control Program (CP) 115
April 1, 1981
The START TAPE command starts the data collection by VK/370 Monitor onto a tape mounted on a 9-track tape drive. Specify "raddr" as the real hexadecimal address of the tape drive that
you want to use. It activates data collection for those
classes of MONITOR CALL previously specified in a KONITOR ENABLE command. The mask that was saved by the KONITOR ENABLE
command is moved into control register 8. The data is collected in two buffer pages in real storage. These pages
are separate from the internal trace table pages. As each
data page is filled, it is written onto the tape. Use BUFFS to specify the number of buffers to be used for
monit.orinq, where "nil may be 1 to 10 and specifies the number
of 4096-byte buffers to be used. If the option is omitted, VM/370 assigns a default. The value of the default depends
upon the model number or type of processor as follows: r -, Model or Processor Default I I Model 135, 138, or 145 2 buffersl I 4331 Processor 2 buffersl I Model 148, 155, or 158 3 buffersl I Model 165 or 168 4 buffersl I 3031, 3032, 3033, or I 4341 processor 4 buffersl It is valid to specify BUFFS 1 only if the PERFORM class of
data collection is the only one enabled with the MONITOR ENABLE command. Once monitoring is in progress with just one
buffer, it is not possible to issue a MONITOR ENABLE command
with other than just the PERFORM class of data collection
specified.
single-buffer operation is useful for basic performance
analysis in minimum main storage confiqurations. When the VM/370 Monitor is started, CP issues a REWIND command
followed by a Set Mode command for the reset value of tape
density.
The user can request a different mode setting by specifyinq
the MODE option in the MONITOR START TAPE command. Kode values of 800, 1600, or 6250 bpi may be specified. If a user specifies a density mode that the tape cannot
handle, the control unit may not return an error condition.
In this case, the mode setting is ignored, and the default
control unit settinq is used.
The START CPTRACE command starts the tracing of events that
occur on the real machine. The events are recorded in the CP internal trace t.able in chronological order. When the end of
the table is reached, recording continues at the beginning of
the table, overlayinq data previously recorded.
116 IBM System Programmer;s Guide
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