Background Information on POSIX and XPG

• Microsoft Windows NT operating system version 3.1

SUMMARY

The portable operating system interface (POSIX) standard was developed by the Institute of Electrical and Electronics Engineers (IEEE). The POSIX kernel interfaces (IEEE 1003.1) provide a basic set of application programming interface (API) functions for the development of applications that are portable across UNIX and other POSIX- compatible operating systems.

Microsoft plans on supporting POSIX.1 with an application subsystem built into Windows NT version 3.1. Microsoft plans to have this subsystem certified for compliance with the FIPS 151-1 test suite. (FIPS refers to the Federal Information Processing Standards Publication Series published by the National Institute of Standards and Technology [NIST].)

The POSIX subsystem allows customers with investments in POSIX applications to use the Windows NT operating system. While this system is provided for compatibility reasons, Microsoft fully expects most development for Windows NT to use the native Win32 API.

The POSIX.2 specification is expected to be released soon. Microsoft is tracking this specification for possible future compliance. Possible options include third-party extensions to the POSIX.1 subsystem in Windows NT.

Information on other POSIX specifications is not currently released. Microsoft will track their requirements and will supply those components in the future. The goal is to have an open system within the Windows Open Services Architecture (WOSA) framework.

Certification encompasses both the hardware and the operating system. For more information on certification, query on the following in the Microsoft Knowledge Base:

   Windows NT and certification and POSIX

MORE INFORMATION

XPG stands for X/Open Portability Guide (begun in 1989). It is a guide developed by X/Open, which was founded in 1984 by Amdahl, Bull, DEC, Fujitsu, HP, Hitachi, IBM, Olivetti, ICL, NCR, NEC, Oki, Siemens Nixdorf, Sun, Unisys, and Unix Intl. X/Open's mission statement is:

   To bring greater value to users from computing through the
   practical implementation of open systems.

There is also an X/Open user council that includes Andersen, Bell, Boeing, British Telecom, Kodak, McDonnell Douglas, IRS, Swedish Telecom, and others. Microsoft is a member of the X/Open Independent Software Vendors along with Novell, Micro Focus, Informix, SCO, and others.

XPG is made up of many components, which form the Common Applications Environment (CAE). X/Open would like vendors to have their XPG pieces branded. Note that branding is different than certification. Branding does not require specific hardware.

Currently, XPG is in revision 4 (XPG4). It differs from XPG3 (1989) mostly in the inclusion of interoperability pieces (for example, the transport interface, file transfer, and mail messaging).

XPG4 is broken down into the following components:

• Operating system and languages
• Data management
• User interface
• General internetworking
• Mainframe internetworking
• PC internetworking
• Media

Operating System and Languages

• Internationalization support in the operating system (Microsoft currently does not have this)
• Portability with POSIX.1 (Microsoft's POSIX.1 is going through NIST certification)
• Standard commands and utilities (either SV utilities or POSIX.2; they expect in the future to make POSIX.2 required)
• ANSI C, ANSI COBOL, Pascal, FORTRAN, and Ada (Microsoft supports all of these except Ada)

Data Management

• ISAM support (Microsoft does not support ISAM)
• Relational ANSI SQL (Microsoft has SQL Server)

User Interface

• X-Windows (supplied for NT by DEC)
• Terminal interface (included with Terminal)

General Internetworking

• BSFT (Byte Stream File Transfer)... "is a command line interface to provide Internet Protocol Suite (IPS) File Transfer Protocol (FTP) functionality as an initiator using OSI FTAM..."
• X.400 (Microsoft Mail version 3.0)
• NFS (available from third parties for MS-DOS, Windows, and OS/2--third parties are working on a solution for NT)
• XTI (possible inclusion in NT)

Mainframe Internetworking

• CPI-C (no support is planned)

PC Internetworking

• (PC) NFS (available)
• LMX Server (SMB 2.0 support)

Magnetic Media

• Available through third parties