Software.

In the early 2000 IBM introduced z/OS, a 64-bit operating system for mainframe computers. MVS followed by OS/390 and now z/OS offers the attributes of modern operating system and yet provides backward compatibility to the older operating system. z/OS supports mainframe staple technologies such as CICS, IMS, DB2, RACF, SNA, WebSphere MQ, REXX, CLIST, SMP/E, JCL, TSO/E, and ISPF.

z/OS also supports 64-bit Java, C/C++, and UNIX (Single UNIX Specification) APIs and applications, with UNIX/Linux-style hierarchical HFS and zFS file systems. As a result, z/OS now can host Oracle database (RDBMS software) and SAP(ERP software). z/OS can communicate directly via TCP/IP and includes a standard HTTP server along with other common services such as FTP, NFS.