The z/OS® operating system consists of base elements and optional features.

• The base elements (or simply elements) deliver essential operating system functions. Base elements include:

  The Base Control Program (BCP)

  The BCP provides essential operating system services. The BCP includes the I/O configuration program (IOCP), the workload manager (WLM), system management facilities (SMF), the z/OS UNIX® System Services (z/OS UNIX) kernel, the program management binder, and other components.

  Common Information Model (CIM)

  CIM is a standard data model for describing and accessing systems management data in heterogeneous environments. It allows system administrators to write applications that measure system resources in a network with different operating systems and hardware.

  Communications Server

  Communications Server (also known as CS z/OS) supports secure TCP/IP, SNA, and UNIX networking throughout an enterprise. It gives you the ability to connect subsystems and applications to each other, and to connect network devices (such as terminals and printers) to the system.

  Cryptographic Services

  Cryptographic Services provides the following base cryptographic functions: data secrecy, data integrity, personal identification, digital signatures, and the management of cryptographic keys. Keys as long as 56 bits are supported by this base element.

  DFSMSdfp™

  DFSMSdfp provides storage, data, program, and device management functions.

  Distributed File Service

  Distributed File Service provides:

  • The DCE file serving (DFS(TM)) component of the Open Group Open Software Foundation (OSF) DCE. The file serving support (the DFS™ client and server) is at the OSF 1.2.2 level.
  • The zSeries® File System (zFS). The zFS is a UNIX file system that can be used in addition to the hierarchical file system (HFS). zFS file systems contain files and directories that can be accessed with the z/OS hierarchical file system file APIs. zFS file systems can be mounted into the z/OS UNIX hierarchy along with other local (or remote) file system types (such as HFS, TFS, AUTOMNT, and NFS). The zFS does not replace the HFS; it is complementary to the HFS.

  Hardware Configuration Definition (HCD)

  HCD defines both the operating system configuration and the processor hardware configuration for a system.

  IBM® HTTP Server

  IBM HTTP Server is the Web server for z/OS. It provides scalable, high performance Web serving for critical e-business applications. It supports Secure Sockets Layer (SSL) secure connections, dynamic caching using the Fast Response Cache Accelerator, multiple IP addresses, proxy authentication, and double-byte character set characters.

  Integrated Security Services

  Integrated Security Services provides base security functions for z/OS. Its components include:

  • DCE Security Server, which uses the limited DES algorithm for encryption.
  • Enterprise Identity Mapping (EIM), which allows you to map a user's identity on one system to the user's identity on another system.
  • Network Authentication Service, which uses the DES algorithm for encryption.

  Interactive System Productivity Facility (ISPF)

  ISPF provides facilities for all aspects of host-based software development. ISPF has four major components: Dialog Manager, Program Development Facility, Software Configuration and Library Manager, and the Client/Server component.

  Job entry subsystem (JES)

  z/OS installations may use one of two job entry subsystems; a job entry subsystem accepts the submission of work for the BCP.

  • JES2 exercises independent control over its job processing functions.
  • JES3 exercises centralized control.

  JES2 is a base element of z/OS; JES3 is an optional feature.

  Language Environment®

  Language Environment provides the run-time environment for programs generated with C, C++, COBOL, Fortran, and PL/I.

  Network File System (NFS)

  NFS acts as a file server to workstations, personal computers, or other authorized systems in a TCP/IP network.

  System Modification Program Extended (SMP/E)

  SMP/E is a tool for installing and maintaining software, and for managing the inventory of software that has been installed.

  Time Sharing Option/Extensions (TSO/E)

  TSO/E allows users to create an interactive session with the z/OS system. TSO provides a single-user logon capability and a basic command prompt interface to z/OS.

  z/OS UNIX System Services (z/OS UNIX)

  z/OS UNIX provides the standard command interface familiar to interactive UNIX users.

• The optional features (or simply features) are orderable with z/OS and provide additional operating system functions. Optional features include:

  DFSMSdss™

  DFSMSdss copies and moves data for backup and recovery, and to reduce free-space fragmentation.

  DFSMShsm™

  DFSMShsm provides automated DASD storage management, including space management for low and inactive data, and availability management for accidental data loss caused by local and site disasters. DFSMShsm also lets you make effective use of tape media.

  DFSMS™ Transactional VSAM Services (DFSMStvs)

  DFSMStvs enables batch jobs and CICS® online transactions to update shared VSAM data sets concurrently.

  DFSORT™

  DFSORT provides fast and easy sorting, merging, copying, reporting, and analysis of your business information, as well as versatile data handling at the record, field, and bit level.

  Infoprint Server

  Infoprint Server allows you to print files on z/OS printers from any workstation that has TCP/IP access.

  Resource Measurement Facility (RMF™)

  RMF gathers data about z/OS resource usage and provides reports at any system in a sysplex.

  System Display and Search Facility (SDSF)

  SDSF provides you with information to monitor, manage, and control your z/OS system.