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History
In 1979, Motorola was developing their new Motorola 68000 CPU and one of their engineers, Jack Kister, decided to set about creating a standardized bus system for 68000-based systems. The Motorola team brainstormed for days to select the name VERSAbus. Kister was later joined by John Black, who refined the specifications and created the VERSAmodule product concept. A young engineer working for Black, Julie Keahey designed the first VERSAmodule card the VERSAbus Adaptor Module used to run existing cards on the new VERSAbus. Sven Rau and Max Loesel of Motorola-Europe added a mechanical specification to the system, basing it on the Eurocard standard that was then late in the standardization process. The result was first known as VERSAbus-E but was later renamed to VMEbus, for VERSAmodule Eurocard bus (although some refer to it as Versa Module Europa). At this point, a number of other companies involved in the 68000's ecosystem agreed to use the standard, including Signetics, Philips, Thomson, and Mostek. Soon it was officially standardized by the IEC as the IEC 821 VMEbus and by ANSI and IEEE as ANSI/IEEE 1014-1987. The original standard was a 16-bit bus, designed to fit within the existing Eurocard DIN connectors. However there have been several updates to the system to allow wider bus widths. The current VME64 includes a full 64-bit bus in 6U-sized cards and 32-bit in 3U cards. The VME64 protocol has a typical performance of 40 MB/s. Other associated standards have added hot-swapping (plug-and-play) in VME64x, smaller 'IP' cards that plug into a single VMEbus card, and various interconnect standards for linking VME systems together. In the late 1990s, synchronous protocols proved to be favourable. The research project was called VME320. The VITA Standards Organization called for a new standard for unmodified VME32/64 backplanes. The new 2eSST protocol was approved in ANSI/VITA 1.5 in 1999. Over the years, many extensions have been added to the VME interface, providing 'sideband' channels of communication in parallel to VME itself. Some examples are IP Module, RACEway Interlink, SCSA, Gigabit Ethernet on VME64x Backplanes, PCI Express, RapidIO, StarFabric and InfiniBand. VMEbus was also used to develop closely-related standards, VXIbus and VPX. VME Early Years (from ANSI/IEEE Std 1014-1987 and ANSI/VITA 1-1994) The architectural concepts of the VMEbus are based on VERSAbus, developed in the late 1970s by Motorola. Motorola's European Microsystems group in Munich, West Germany, proposed the development of a VERSAbus-like product line based on the Eurocard mechanical standard. To demonstrate the concept, Max Loesel and Sven Rau developed three prototype boards: (1) a 68000 CPU board; (2) a dynamic memory board; (3) a static memory board. They named the new bus VERSAbus-E. This was later renamed "VME", short for Versa Module European, by Lyman (Lym) Hevle, then a VP with the Motorola Microsystems Operation. (He was later the founder of the VME Marketing Group, itself subsequently renamed to VME International Trade Association, or VITA). VME is the acronym for VERSA-module Europe. In early 1981, Motorola, Mostek and Signetics agreed to jointly develop and support the new bus architecture. These companies were all early supporters of the 68000 microprocessor family. John Black of Motorola, Craig MacKenna of Mostek and Cecil Kaplinsky of Signetics developed the first draft of the VMEbus specification. In October 1981, at the System '81 trade show in Munich, West Germany, Motorola, Mostek, Signetics/Phillips, and Thomson CSF announced their joint support of the VMEbus. They also placed Revision A of the specification in the public domain. In August 1982, Revision B of the VMEbus specification was published by the newly-formed VMEbus Manufacturers' Group (VITA). This new revision refined the electrical specifications for the signal line drivers and receivers and brought the mechanical specification further in line with the developing IEC 297 standard (the formal specification for Eurocard mechanical formats). In latter 1982, the French delegation of the International Electrotechnical Commission (IEC) proposed Revision B of the VMEbus as an international standard. The IEC SC47B subcommittee nominated Mira Pauker of Phillips, France, the chairperson of an editorial committee, thus formally starting international standardization of the VMEbus. In March 1983, the IEEE Microprocessor Standards Committee (MSC) requested authorization to establish a working group that could standardize the VMEbus in the US. This request was approved by the IEEE Standards Board and the P1014 Working Group was established. Wayne Fischer was appointed first chairman of the working group. John Black served as chairman of the P1014 Technical Subcommittee. The IEC, IEEE and VMEbus Manufacturers Group (now VITA) distributed copies of Revision B for comment and received the resulting requests for changes to the document. These comments made it clear that it was time to go past Revision B. In December 1983, a meeting was held that included John Black, Mira Pauker, Wayne Fischer and Craig MacKenna. It was agreed that a Revision C should be created and that it should take into consideration all the comments received by the three organizations. John Black and Shlomo Pri-Tal of Motorola incorporated the changes from all sources into a common document. The VMEbus Manufacturers Group labelled the document Revision C.1 and placed it in the public domain. The IEEE labelled it P1014 Draft 1.2 and the IEC labelled it IEC 821 Bus. Subsequent ballots in the IEEE P1014 Working Group and the MSC resulted in more comments and required that the IEEE P1014 draft be updated. This resulted in the ANSI/IEEE 1014-1987 specification. In 1989, John Peters of Performance Technologies Inc. developed the initial concept of VME64: multiprocessing address and data lines (A64/D64) on the VMEbus. The concept was demonstrated the same year and placed in the VITA Technical Committee in 1990 as a performance enhancement to the VMEbus specification. In 1991, the PAR (Project Authorization Request) for P1014R (revisions to the VMEbus specification) was granted by the IEEE. Ray Alderman, Technical Director of VITA, co-chaired the activity with Kim Clohessy of DY-4 Systems. At the end of 1992, the additional enhancements to VMEbus (A40/D32, Locked Cycles, Rescinding DTACK*, Autoslot-ID, Auto System Controller, and enhanced DIN connector mechanicals) required more work to complete this document. The VITA Technical Committee suspended work with the IEEE and sought accreditation as a standards developer organization (SDO) with the American National Standards Institute (ANSI). The original IEEE Par P1014R was subsequently withdrawn by the IEEE. The VITA Technical Committee returned to using the public domain VMEbus C.1 specification as their base-level document, to which they added new enhancements. This enhancement work was undertaken entirely by the VITA Technical Committee and resulted in ANSI/VITA 1-1994. The tremendous undertaking of the document editing was accomplished by Kim Clohessy of DY-4 Systems, the technical co-chair of the activity, with great help from Frank Hom who created the mechanical drawings and exceptional contributions by each chapter editor. Additional enhancements proposed to the VME64 Subcommittee were placed in the VME64 Extensions Document. Two other activities began in late 1992: BLLI (VMEbus Board-level Live Insertion Specifications) and VSLI (VMEbus System-level Live Insertion with Fault Tolerance). In 1993, new activities began on the base-VME architecture, involving the implementation of high-speed serial and parallel sub-buses for use as I/O interconnections and data mover subsystems. These architectures can be used as message switches, routers and small multiprocessor parallel architectures. VITA's application for recognition as an accredited standards developer organization of ANSI was granted in June 1993. Numerous other documents ( including mezzanine, P2 and serial bus standards) have been placed with VITA as the Public Domain Administrator of these technologies. VMEbus History Description |