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1、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 T
2、hey 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, par
3、titioned, ).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
4、(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
5、, 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
6、 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) Logica
7、l 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 Physi
8、cal 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 par
9、titioned 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 with
10、out 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 a
11、nd 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 easier2
12、0) 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 p
13、arameters. 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. DD - The Data Definition provides inputs andoutputs to the execution program on the EXECstatement. This statement links a data set orother
14、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.
15、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 com
16、pleteparameter 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. A job step consists of the JCLs thatcontrol execution of a program. A job step is
