IEEE 896.5

Description / Abstract: The initial work in development of the Futurebus+m specification was done under the auspices of the IEEE Computer Society Microprocessor Standards Committee. In 1988, both the United States Navy's Next Generation Computer Resources (NGCR) Backplane Standards Committee and the VFEA International Trade Association (VITA), a trade association of both VME64 manufacturers and users, agreed to join the IEEE in revising ISODEC 10857: 1994 [ANSVIEEE Std 896.1, 1994 Edition].¹ In early 1989, the Multibus Manufacturers Group (MMG), a trade association of both Multibus I and Multibus II manufacturers and users, also agreed to join this effort.

The primary goal of all four groups (IEEE, U.S. Navy, VITA, and MMG) was to provide a new microprocessor bus standard that would be commercially viable and that would be acceptable to the two manufacturer groups and the three user communities.

This work resulted in the IEEE 896 family of standards, of which two have become International Standards. ISOííEC 10857: 1994 defines the logical functionality of the set of signals that make up the bus. IEEE Std 896.2-1991 describes and specifies the physical layer (i.e., electrical characteristics, pinouts, connector locations, module sizes, etc.) required. It also contains the first three application environment profiles. IEEE Std 896.3- 1993 describes Futurebus+ recommended practices and specifies system-level concerns when using a Futurebus+ backplane in the design of a system. IEEE Std 896.4-1993 describes conformance test requirements for Futurebus+. IEEE Std 896.9-1994 [B3]² defines extensions to the base Futurebus+ standards that are used in extremely fault-tolerant systems. This International Standard describes and specifies the physical layer required for harsh environments that require rugged, fault-tolerant, survivable systems, as in military applications. The three profiles in this International Standard describe functional requirements with pointers to existing standards that select and bind options within those standards. It is these profiles, not the component standards, to which manufacturers may claim conformance. An end user who then purchases modules complying to a given profile from a range of suppliers has a higher assurance of interoperability.

Three physical form factors are incorporated into the military profiles included in this International Standard at the time of publication. Additional profiles that address other aspects of the Futurebus+ computer spectrum are being developed by the working group. These will appear in companion standards. As new physical SYSTEMSor electrical layer requirements (e.g., a different connector type or driver technology) emerge, new profiles wili be developed to address the enhanced capabilities available from newer technologies; this is part of the reason for layering the Futurebus+ standards.

The scope of this International Standard has been restricted to exclude some of the higher level system requirements associated with bus-based computer systems. These are addressed in companion standards such as IEEE Std 896.3-1993, IEEE Std 896.4-1993, and IEEE Std 896.9-1994 [B3]. The software interface to common-node capabilities as shared by Futurebus+ and Serial Bus (IEEE P1394) is defined by ISO/lEC 13213: 1994. This interface provides the framework for defining processor, memory, and VO nodes on the Futurebus+, as well as bridges to other buses (see IEEE P1014.1 [B4]).

¹Information on references can be found in clause2.

². b e numbers in brackets preceded by the letter B correspond to those of the bibliography in annex E.