IBMmainframejcl义.docx

1) Disks or tape are most frequently used for storing data sets on a long term basis. Disk drives are known as direct access storage devices (DASD)2) An access method is an interface between an application program and the physical operations of storage devices3) Files in z/OS have a different name They are called data sets. When you create (allocate) a data set, you have to tell z/OS:1. The record length (how long each record will be) and block size.2. Volume Serial Number of the disk (label) that the data set will reside.3. How big (how many tracks/cylinders)? 4. Dataset type (sequential, partitioned, ).4) A data set name can be one name segment, or a series of joined name segments. Each name segment represents a level of qualification. For example, the data set name STU237.SEU.JCL is composed of three name segments. The first name segment on the left is called the high-level qualifier (HLQ), and the last name segment on the right is the lowestlevel qualifier (LLQ).5) Segments or qualifiers are limited to eight characters, the first of which must be alphabetic (A to Z) or special character (#, , $). The remaining seven characters are either alphabetic (a-z), numeric (0-9), special, or a hyphen (-). Name segments are separated by a period (.). Including all name segments and periods, the length of the data set name must not exceed 44 characters6) ?A logical record is a unit of information (for example, a customer, an account, a payroll employee, and so on). It is the smallest amount of data to be processed, and it is composed of fields that contain information recognized by the processing application program7) It is the smallest amount of data to be processed, and it is composed of fields that contain information recognized by the processing application program8) Logical records are grouped within physical records named blocks. BLKSIZE indicates the length of those blocks9)10) data set parameters :RECFM (Record Format):F, FB, V, VB, U LRECL (Logical Record Length):80, 140, etc. BLKSIZE (Block Size):800, 1400, etc. DSORG: PS, PO data set type11) Data set type Physical Sequential Data Set PS Partitioned Data Set (PDS) PO (Partition Organization) Partitioned Data Set/Extended POE12) A sequential data set (PS) consists of one or more records that are stored in physical order and processed in sequence. New records are appended to the end of the data set.13) A partitioned data set (PDS) is a collection of sequential datasets, called members. Each member is like a sequential data set and has a simple name, which can be up to eight characters long14)15)16) A catalog records the location of files. When a data set is cataloged, it can be referred to by name without the user needing to specify where the data set is stored17) To find a data set that you have requested, z/OS must know three pieces of information:1. Data set name.2. Volume name.3. Unit (the volume device type, such as a 3390 disk or 3590 tape) A catalog is used to store and retrieve the UNIT and VOLUME information of a data set.18) A typical z/OS system uses one master catalog and numerous user catalogs connected to it19) The master catalog usually stores only the system data sets and name of the user catalogs. The user catalog stores user data sets. This will make migration much easier20) JCL is used to tell the system whatprograms to execute, what datasetsthese programs will use, what is thedisposition of data sets when theprogram execution ends.21) JOB - Provides a name (jobname) to thesystem for this batch job. It can optionallyinclude accounting information and a few jobwide parameters.l EXEC - Provides the name of a program toexecute. There can be multiple EXECstatements in a job. Each EXEC statementwithin the same job is a job step.l DD - The Data Definition provides inputs andoutputs to the execution program on the EXECstatement. This statement links a data set orother I/O device to a ddname coded in theprogram.22) Format of JCL Statements1. Identifier field: Indicates to the systemthat a statement is a JCL statement ratherthan data. Columns 1 and 2 of all JCLstatements contain /.2. Name field: The name is 1 through 8alphanumeric or national characters($, #, ).3. Operation field: The operation fieldspecifies the type of JCL statement.4. Parameter, or operand field: Containsparameters separated by commas.23)24) When the total length of the fields on a controlstatement exceeds 71 columns, continue thefields onto the next line.1. Interrupt the field after a completeparameter or subparameter, including thecomma that follows it, at or before column 71.2. Code / in columns 1 and 2 and a blankcharacter in column 3 of the followingstatement.3. Continue the interrupted parameter or fieldbeginning in any column from 4 through 16.Continuing JCL Statements25) You enter a program into theoperating system to execute as a jobstep.lA job step consists of the JCLs thatcontrol execution of a program.lA job step is identified by an EXECstatement. The job step can alsocontain data needed by the program26) A job is a collection of related job steps. A jobis identified by a JOB statement.27) JCL Special Characters (cont.) & To identify a symbolic parameter.ex. &LIB& To identify a temporary data set name.ex. &TEMP128) (blank)29) 1 . Each jobname should be unique.(can have the same jobname)2. The jobname must begin in column 3.3. jobname is 1 through 8 alphanumeric(A-Z,0-9) or national ($, #, ) characters.4. The first character must be alphabetic ornational ($, #, ).5. The jobname must be followed by at leastone blank.JOB statement30)31)32) The EXEC statementmarks the beginning of each job step in ajob or a procedure33) A stepname is optional. When a stepnameis needed, it must be unique within the job.lThe stepname is 1 through 8 alphanumericor national characters ($, #, ).lThe first character must be alphabetic ornational character ($, #, ).lThe stepname must be followed by at leastone blank.lAn EXEC statement has two kinds ofparameters: positional and keyword.34) An EXEC statement must contain one ofthe positional parameters: PGM, PROC,or procedure name. Use the PGM parameter to name theprogram that the system is toexecute.lExample of the PGM Parameter:/STU278A JOB CLASS=A,/STEP1 EXEC PGM=LAB1Use the PROC parameter to specify thatthe system is to call and execute acataloged or in-stream procedureExamples of the PROC Parameter:1. /STEP1 EXEC PROC=MYPROC2. /STEP2 EXEC MYPROC35) What is JCL procedure (PROC)?lSome programs and tasks require a largeramount of JCL than a user can easilyenter. JCL for these functions can be kept in procedure librariesSuch a procedure is sometimes known asa cataloged procedure.36)37) The DD StatementlUse the DD (Data Definition) statementto specify the input and outputresources needed for the program.lDD statement Syntaxa) /ddname DD positional-parameter,keyword-parameter.38) The various DD Statement parameters1. ddname - DD statement name2. DSN data set name3. &name temporary data set4. DISP specification of actions on thedata that will be processed, or aftersuccessful execution of the job or afterunsuccessful execution of the job.39) The ddname specifies the name of theDD statement.l1 through 8 alphanumeric or national ($,#, ) characters.lThe first character must be alphabeticor national ($, #, )40) Temporary Data Sets: The namestarts with two ampersands (&)followed by 1 to 8 characters.ex. /step1 DD dsn=&temp0141) DISP= Data set disposition, such aswhether the data set needs to be created oralready exists, and whether the data setcan be shared by more than one job1. NEW - A new data set is to be created in this step.2. OLD - The data set exists before this step and that this step requires exclusive (unshared) use of the data set.3. SHR - The data set exists before this step and that other jobs can share it, that is, use it at the same time. 4. MOD - Indicates one of the following: a) The data set exists and records are to be added to the end of it. The data set must be sequential.b) A new data set is to be created. In either case, MOD specifies exclusive (unshared) use of the data set5. DELETE - the data set is to be deleted if this step terminates normally.6. KEEP - the data set is to be kept on the volume if this step terminates normally.7. PASS - the data set is to be passed for use by a subsequent step in the same job.8. CATLG - if the step terminates normally, the system is to place an entry pointing to the data set in the system or user catalog.9. UNCATLG - if the step terminates normally, the system is to delete (1) the entry pointing to the data set in the system or user catalog.42)43) SPACE= allocate storage space for new datasets on DASD.l The SPACE parameter has no meaning fortape volumes.44) Ex. Allocate a PS data set:/ SPACE=(TRK,(5,2)*Maximum allocation 35 tracks, nodirectory specified for PS.Ex. Allocate a PO data set:/ SPACE=(CYL,(2,1,5)*Maximum allocation 17 cylinders,5 is the directory block.45) The special DD parameter DUMMY - Results in a null input orthrowing away data written to thisddname.ex. /DD1 DD DUMMY46) Utilities are pre-written programs thatperform commonly needed functions. Useutility programs to assist you in organizingand maintaining data. Data Set Utility Programs: You can usedata set utility programs to copy, move,reorganize, change, or comp