z / OS
| z / OS | |
|---|---|
| developer | IBM |
| License (s) | Proprietary , Monthly License Fee (MLC); Payment based on current usage (VWLC, EWLC, AWLC, EAWLC, IWP); Reduced payment (zELC, zNALC, "Solution Edition") for many applications |
| First publ. | 2001 |
| Current version | Version 2.4 (V2R4) (September 30, 2019) |
| Kernel | Monolithic |
| ancestry |
OS / 360 ↳ OS / MFT ↳ OS / MVT MVS ↳ MVS / XA ↳ MVS / ESA OS / 390 |
| Architecture (s) | z / Architecture (2817, 2818, 2827, 2098, 2097, 2096, 2094, 2084, 2066, 2064) |
| Languages) | English and other languages |
| Others | mainly written in PL / X , HLASM , and C / C ++ . Usable programming languages: Java , C , C ++ , COBOL , PL / I , HLASM , FORTRAN , REXX , Pascal and others |
| IBM z / OS | |
z / OS is an operating system for IBM - mainframe , distributed since 2,001th Its roots go back to the 1950s. Only the third generation of the then IBM mainframe operating systems from the 1960s could be used for both scientific and business purposes and was named in association with the 360 degrees of the compass rose OS / 360 due to its versatility .
properties
S / 360 , S / 370 , ESA / 390 etc. were actually more like the hardware components on which different operating systems (including MVT , MVS , MVS / ESA , OS / 390 and VM ) could run. The most important development stages in the software sector were the introduction of MVS in the 1970s (24 bit) and MVS / XA in the 1980s (31 bit - the 32nd bit was used for downward compatibility) and the successor OS / 390. Around the turn of the millennium, the 64-bit architecture was introduced with z / OS. As the youngest generation in over 40 years of development history, z / OS still occupies a dominant position among mainframe operating systems.
In the parallel Sysplex network, a closely coupled cluster of IBM mainframes, z / OS still exceeds the availability rate of 99.999% specified for the previous generation OS / 390 (so-called five-nines, which corresponds to a downtime of five minutes per year) : The z in the name stands for zero downtime . According to the definition of IBM, a downtime is always an unplanned business interruption.
Scalability
The operating system supports the scalability of a mainframe with up to 640 64-bit IBM processors and almost all high-level programming languages . Various subsystems enable simultaneous operation in dialog and in batch ( batch processing ). The integrated z / OS UNIX (component z / OS Unix System Services ) ensures the connection to the Unix world and the open systems world. (z / OS UNIX should not be confused with zLinux. zLinux can be installed independently of z / OS as an independent operating system on IBM Z hardware.)
The connection to other computers or to the Internet takes place both via proprietary protocols and via TCP / IP . Extensive cryptography functionality with support not only for standards such as TLS , SET , VPNs , and hardware isolation allow the creation of secure application systems.
The interaction of z / OS with the System z hardware is optimized for very high I / O volumes (see inputs and outputs , transactions ) with a large number of users and with the greatest possible security (data integrity, access protection).
Components or standard software that is frequently used under z / OS
- System for entering program calls and for sequence control
- JES ( Job Entry Subsystem ) for executing JCL scripts
- JCL ( Job Control Language ), a control language for batch processing
- OPC ( Operation Planning and Control ), a tool for job flow control
- JES ( Job Entry Subsystem ) for executing JCL scripts
- Access control
- RACF (Resource Access Control Facility) for authentication , authorization and auditing
- Alternative: ACF2
- Databases and transaction monitors
- CICS ( Customer Information Control System ), a transaction system
- DB2 , a relational database system
- IMS ( Information Management System ), an information system that contains, among other things, a transaction monitor (IMS / DC)
- Interactive access with command line or menu access
- TSO ( Time-Sharing Option ), an interactive command line interpreter
- ISPF ( Interactive System Productivity Facility ), a menu-driven user interface for use under TSO
- UNIX shell via SSH (or telnet, rlogin). Various UNIX shells are available with sh, tcsh or bash.
- TSO ( Time-Sharing Option ), an interactive command line interpreter
- Other components
- WLM ( Workload Manager ) and SRM ( Systems Resource Manager ) for managing resources
- RMF ( Resource Measurement Facility ) and SMF ( System Management Facility ) for the collection and evaluation of operational data
- SMP / E (System Modification Program / Extended) for the installation and maintenance of the operating system and the components
- Special hardware
- Assist Processors , special processors for the execution of partial tasks (e.g. Java VM )
literature
- Mike Ebbers, Bill O'Brien, Bill Ogden: Introduction to the New Mainframe. z / OS basics . IBM, International Technical Support Organization, Poughkeepsie NY 2006, ISBN 0-7384-9597-2 , ( IBM redbooks , SG 24-6366-00).
- Wolfram Greis: The IBM mainframe architecture . Open Source Press, Munich 2005, ISBN 3-937514-05-8 , (A practice-oriented and compact introduction).
- Paul Herrmann, Wilhelm Gustav Spruth: Introduction to z / OS and OS / 390. Web services and Internet applications for mainframes . 3rd edition, Oldenbourg, Munich 2012, ISBN 978-3-486-70428-0 .
- Michael Teuffel, Robert Vaupel: The z / OS operating system and the zSeries , Oldenbourg Verlag, Munich 2004, ISBN 3-486-27528-3 .