System Generator (SysGen) is a two-stage process for installing or updating OS/360, OS/VS1, OS/VS2 (SVS), OS/VS2 (MVS) and cost systems derived from it. There is a similar process for, for example, DOS/360, which is not covered by this article. Also, some details have changed between the OS/360 release and many details are not brought to the newer system.
There are several reasons that IBM provides the process of making the system rather than simply providing a mechanism to restore the system from tape to disk. The/360 system does not have an I/O device that identifies itself, and the customer can request the installation of I/O devices at random addresses. As a result, IBM must provide a mechanism for customers to determine I/O configuration to OS/360. Also, OS/360 supports several different options; IBM needs a way for customers to choose the appropriate code for the required options on a particular installation.
The SysGen process runs as a series of jobs under the control of the operating system. For new installations, IBM provides a complete pre-configured driver system, intended only to prepare and run sysgen, not for production use.
Before running Sysgen, the customer must initialize a set of distribution volumes and return a set of distribution libraries from tape to that volume. These libraries include data that the sysgen process will be copied to the target library, input to the utility used by the sysgen process, the macro definitions used by the sysgen process and the load module that the sysgen process will include when connecting the load module into the target library.
Phase 1 is a compilation of a sequence of macro assembler instructions that describes the configuration to be installed or updated. Assembler does not actually compile any object code, but instead compiles a series of PUNCH pseudo-ops to generate a work stream for Phase 2. Because IBM changed the nomenclature for the OS/360 option, it also changed the Sysgen macro definition to use a new name for the option.
The TYPE keyword in the CTRLPROG macro in input Phase 1 specifies the type of control program. By Removing 13 old SSS , MSS and MPS were replaced by PCP , MFT > and MVT . The next M65MP type is the MVT variation.
The SCHEDULER macro in the Stage 1 input specifies the type of scheduler; Release 13 still uses the SEQUENTIAL and PRIORITY values, but it's then replaced by the value used for the TYPE keyword in CTRLPROG macro.
These types
- PCP
- Primary Control Program ( Option 1 )
- MFT
- Perform Multiprogramming with fixed Tasks (MFT) ( Option 2 )
- MVT
- Multiprogramming with Variable of Taskks (MVT) ( Option 4 )
- M65MP
- Model 65 Multi-Processing, special case MVT.
The GENERATE macros in the Sysgen input can be of several types:
- The full generation of the operating system.
- Generation of compilers and related libraries.
- I/O configuration update
For MVT (either TYPE = MVT or TYPE = M65MP ) with TSO, the macro TSOGEN plays the same role as GENERATE . Both macros analyze the options specified in the previous macro call and suppress the Stage 2 work stream.
Stage 2 workflow uses a variety of utilities, including assembler and link editor.
This process is now outdated; it was originally replaced by the use of SMP/E, IOCP and MVSCP, then by SMP/E and Hardware Configuration Definition (HCD).
Video System Generation (OS)
See also
- Software life cycle release
- Software installs
Maps System Generation (OS)
References
External links
- IBM. ESCON Channel-to-Channel Initial Programs Initial/Output User's Guide. GC38-0401-00. IBM. Planning HCD z/OS V1R1.0 . GA22-7525-00.
Source of the article : Wikipedia
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