IBM OS/390 User Manual
Understanding tool provides a graphical analysis of your VSE/ESA JCL job
stream. You can find further details at the following World Wide Web sites:
stream. You can find further details at the following World Wide Web sites:
http://www.software.ibm.com/ad/va2000
http://www.software.ibm.com/ad/cobol
http://www.software.ibm.com/ad/cobol
The JCL Analyzer is shipped as part of VSE Central Functions in VSE/ICCF
library 59. It consists of a number of members, including ARDWREAD, which is a
detailed description of the JCL Analyzer and its functions. All the other related
library member names begin with the characters ARDW.
library 59. It consists of a number of members, including ARDWREAD, which is a
detailed description of the JCL Analyzer and its functions. All the other related
library member names begin with the characters ARDW.
There is a brief description of this new function in the manual,
VSE/ESA
Enhancements Version 2 Release 3, SC33-6629
4.3.6 Device Address Specifications
In VSE, the Logical Unit Address, is the symbolic link between the program and
the external units (tape drive, printer, and so on) it uses. The Logical Unit
Address is a name in the form of SYSnnn, such as SYS004 or SYSLST. The
Logical Unit Address is specified by the programmer on the DTF using the
DEVADDR=SYSnnn keyword; for this reason, it is often referred to as the
the external units (tape drive, printer, and so on) it uses. The Logical Unit
Address is a name in the form of SYSnnn, such as SYS004 or SYSLST. The
Logical Unit Address is specified by the programmer on the DTF using the
DEVADDR=SYSnnn keyword; for this reason, it is often referred to as the
″
Device Address
″,
a term easily confused with
″
Unit Address
″,
which refers to
the external unit associated with the Logical Unit Address, such as the 3205
printer at address 00E.
printer at address 00E.
In other words, the terms Logical Unit Address and Device Address both refer to
the SYSnnn name, where Unit Address refers to the hardware device at address
CUU.
the SYSnnn name, where Unit Address refers to the hardware device at address
CUU.
In the VSE JCL, the ASSGN statement is used to associate a Device Address to a
Unit Address; for example:
Unit Address; for example:
// ASSGN SYS010,FEF
where SYS010 is the device address specified in the program, and FEF is the unit
address of a real or virtual printer device.
address of a real or virtual printer device.
An ASSGN statement is normally required for every non-disk file used by the
program, although Tape Management Software products generally remove the
requirement for tapes.
program, although Tape Management Software products generally remove the
requirement for tapes.
There is no exact equivalent for the Device Address in MVS JCL. The association
between a file and a particular device is established by Device Allocation, a
system function invoked by the initiator. The equivalent of the above ASSGN card
depends on what DDNAME is used in MVS for a particular file, which could be,
for example:
between a file and a particular device is established by Device Allocation, a
system function invoked by the initiator. The equivalent of the above ASSGN card
depends on what DDNAME is used in MVS for a particular file, which could be,
for example:
//SYS010 DD SYSOUT=...
or
//REPORT1 DD SYSOUT=...
One may wonder, when converting VSE JCL to MVS, what to do with the Device
Addresses, ASSGN cards, and what DDname should be used for card and print
files. Here are some guidelines:
Addresses, ASSGN cards, and what DDname should be used for card and print
files. Here are some guidelines:
•
For disk - the DEVADDR should be ignored, and the DTFname should be
used as MVS DDname.
used as MVS DDname.
•
For labeled tape - the DEVADDR should be ignored, except when the ASSGN
statement specifies a tape density, or when assigning several files to the
same unit. The DTFname should be used as MVS DDname.
statement specifies a tape density, or when assigning several files to the
same unit. The DTFname should be used as MVS DDname.
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VSE to OS/390 Migration Workbook