I.
z/os
1. data set name, temporary dataset, symbolic variable
1) Data sets are the files that contain programs and data
2) 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 lowest level qualifier (LLQ).
3) 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 (.).
4) Including all name segments and periods, the length of the data set name must
not exceed 44 characters 5) in jcl:
& To identify a symbolic parameter. ex. &LIB
&& To identify a temporary data set name. ex. &&TEMP1
6) Temporary Data Sets: The name
starts with two ampersands (&&) followed by 1 to 8 characters. ex. //step1 DD dsn=&&temp01
2. IBM utility program: IEFBR14, IEBGENER, IEBCOPY, IDCAMS
1) Utilities are pre-written programs that
perform commonly needed functions. Use utility programs to assist you in organizing
and maintaining data. Data Set Utility Programs: You can use data set utility programs to copy, move, reorganize, change, or compare data at the
data set or record level. Data Set Utilities start with IEBxxxxx 2) IEBCOPY: to copy, compress, or merge
partitioned data sets or PDSEs. IEBGENER: Copy records from a
sequential data set or convert a data set from sequential organization to partitioned organization.
IEFBR14: Dummy utility
a. IEBCOPY (Library Copy) Program:
- Copy partitioned data set(PDS). (ISPF 3.3 in batch mode)
- Copy partitioned data set members. - Compress partitioned data sets in place. - Make a copy of a partitioned data set.
- Merge partitioned data sets.
- Create a sequential form of a PDS for backup or transport.
- Copy and re-block load modules b. IEBGENER
?Use IEBGENER to copy one sequential file to another. (ISPF 3.3 in batch mode) ?To print sequential data sets or members of partitioned data sets.
?To create partitioned data set members c. IEFBR14
?IEFBR14 is a null program. It does nothing， it executes a single
statement, which specifies the end of program.
?It’s used as a dummy step, or to allocate/delete data sets
3) IDCAMS：主要用于创建和操作VSAM数据集和目录操作 3. LPAR is what? Why use it?
1) Logical PARtition
2) 实际上是指通过虚拟手段一组逻辑上独立的资源可以用来运行一个系统，逻
辑上可以看成一个独立的计算机。大型机操作系统总是在LPAR模式中运行，即使一台大型机只运行一个OS。LPAR可以运行各种系统，不必是z/OS 3) why?
a. Logical partitions are, in practice, equivalent to separate mainframes. Each LPAR runs its own operating system (OS). b. Reduce number of servers(mainframes). c. Running different OS.
d. Running different versions of OS
4. z/os subsystem and component: JES, TSO, ISPF, SDSF, RACF
1) RACF (Resource Access Control Facility) is a z/OS security subsystem 2) TSO/E(Time Sharing Option/Extensions).
? ISPF(Interactive System Productivity Facility).
? TSO/E and ISPF allow you to log on to the z/OS system, run programs, and manipulate data files
3) JCL (Job Control Language) is used to submit batch job to z/OS to execute 4) JES (Job Entry Subsystem)receive jobs into the operating system, to schedule
them for processing by z/OS, and to control their output processing 5) SDSF:IBM的“系统显示与查询工具”（简称SDSF）是OS/390的可选产品，可
以向用户提供大量的信息以协助用户监测、管理以及控制MVS/JES2系统
5. logical record, physical record, why blocking? why a physical record contains many
logical records
1) A record is a fixed number of bytes containing data and is the basic unit of
information used by a program running on z/OS
2) 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 program
3) Logical records are grouped within physical records named blocks. BLKSIZE
indicates the length of those blocks 4) block为了节省io and save space
6. z/os master and user catalog, what kind of information saved in catalog?
1) 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 stored
2) 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.
3) A typical z/OS system uses one master catalog and numerous user catalogs
connected to it
a. The master catalog usually stores only the system data sets and name of the user catalogs.
b. The user catalog stores user data sets.
c. This will make migration(迁移) much easier
7. characteristic of sequential data set and partitioned data set, directory block
1) 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.
2) 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 long
3) directory block stores the entry of each members
8. JCL coding rules, how to continue to next line
1) JCL is used to tell the system what programs to execute, what datasets these
programs will use, what is the disposition of data sets when the program execution ends.
2) Format of JCL Statements(no period)
a. Identifier field: Indicates to the system that a statement is a JCL statement rather than data. Columns 1 and 2 of all JCL statements contain //.
b. Name field: The name is 1 through 8 alphanumeric or national characters($, #, @).can’t appear at Columns 1 and 2
c. at least one space between name field and operation field
d. Operation field: The operation field specifies the type of JCL statement. e. at least one space between operation field and parameter field
f. Parameter, or operand field: Contains parameters separated by commas.
