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Encore computer 91 System


  • High Performance Multiprocessor Systems Optimized for Real-Time Applications

  • Highly Integrated, Fully Symmetric Single Board Multiprocessors

  • RISC CPU Architecture (Motorola 88000 family)

  • Power Domain Multi-Operating System Architecture

  • Input/Output Connectivity: Industry Standard VME, VME64, Ethernet and SCSI

  • Real-Time Features: HSD Support, Reflective Memory, Hardware Interrupts, Real-Time Clock and Timers

  • Optimizing Compilers: ANSI Standard C, Parallel Ada, Ada Real-Time Executive, FORTRAN 77 with Real-Time Extensions and Parallel FORTRAN

  • Data Communications: Ethernet, with TCP/IP and NFS Support and X.25

  • State of the Art Software Development Tools, CASE and Parasight



• Open architecture
• Scalable system design
• Parallel processing power
• Compatibility with MPX-32 applications
• Standards and uncompromised real-time performance
• Domain resource management Control


The Encore 91TM series is the first member of the new Encore 90TM family of open systems targeted to real-time applications. These high-performance multiprocessor systems are built using industry standard hardware platforms, 
standard I/O interfaces and standard OS and application software. The Encore 91 series has been designed for maximum flexibility to meet the requirements of end users and system integrators.

The hardware architecture of the Encore 91 series is based on the Motorola high-performance 88100 25MHz RISC processor. A basic system is a highly integrated fully symmetrical single board multiprocessor. The single board includes two or four 88100 processors with supporting cache memory, 16 megabytes of shared main memory, two synchronous SCSI ports, an EthernetTM port, 4 asynchronous ports, real-time clocks, timers, interrupts and a VME-64 bus interface. The VME-64 bus provides full compatibility with VME plus enhancements for greater throughput. Shared main memory may be expanded to 272 megabytes (mb) by adding up to four expansion cards. The expansion memory boards have the same high-speed access characteristics as local memory.


Encore’s tradition of high-performance real-time capabilities continues with the Encore 91. In addition to the real-time enhancements to the processor card and bus design, the Encore 91 optionally provides Reflective Memory Systems and High-Speed Data connectivity. The HSD interface developed by Encore is the industry’s de facto standard for high-speed device connectivity. Reflective Memory is Encore’s award winning memory interconnect technology which provides deterministic tight coupling of distributed systems.

Reflective Memory allows for multiple Encore 91 systems to be tightly coupled together to form large scale systems. Reflective Memory is fully supported on Encore’s CONCEPT 32 series of products; therefore, heterogeneous combinations of Encore 91 and CONCEPT 32 systems can be applied to solve the wide ranging demands of real-time applications.

Encore’s innovative operating system design reconciles the competing requirements for standards based systems software and uncomprised real-time performance. The Power DomainTM multi-operating system design harnesses the power of AT&T’s system V.3.2 UNIXR (UMAXTM V) and Encore’s POSIXTM compliant MicroMPXTM real-time kernel. UMAX V provides powerful software capabilities for real-time applications, as well as general purpose UNIX computing. MicroMPX is utilized for running real-time applications within a deterministic time-critical environment. Both operating system environments are symmetrical multithreaded implementations that take full advantage of the tightly coupled parallel architecture of the Encore 91 series systems. MicroMPX retains a large degree of compatibility with MPX-32TM used with Encore’s CONCEPT 32 real-time systems. In addition UMAX V and MicroMPX are fully integrated to present a single operational environment.

A range of packaging options is available including a compact desk-high cabinet and 19-inch rack-based cabinets for computer room applications housing one or two Encore 91 series systems. Customers may purchase the required chassis, boards, power supplies and cooling for mounting in their own cabinets.

The Encore 91 series system conforms to the Binary Compatibility Standard (BCS) defined for the Motorola 88000 family of processors and UNIX V.3.2. By conforming to the standard, a wealth of off-the-shelf applications is available to users of the Encore 91 series systems. These applications may run under UNIX while the remainder of the system is performing real-time tasks under control of MicroMPX.

Central Processor
The Encore 91 series is a multiprocessor-based computer system configured with two or four Motorola model 88100 processors. The processors are implemented using Motorola’s HCMOS technology. All data paths and registers are 32-bits wide. The 88100 is a RISC (Reduced Instruction Set Computing) microprocessor with 51 instructions – most of which execute in one clock cycle. The instructions that exceed one clock cycle, such as memory reference and floating point instructions, execute in a pipelined fashion. Pipelining of these instructions allows them to effectively execute in one clock cycle. The Encore 91 series clock frequency is 25 Megahertz. So the basic instruction execution elapsed time is 40 nanoseconds.

The Encore 91 series 88100 central processor supports seven data types – from individual bits, to integer arithmetic, to floating point. The floating point format is IEEE 754, single precision (32 bits) or double precision (64 bits).

To further enhance performance of each 88100 processor, the Encore 91 series utilizes 88200 Cache Memory Management Units (CMMUs). The CMMUs monitor the memory bus for write cycles in order to ensure that its on-chip cache is updated with new information when data in the main shared memory is changed. This function of the CMMU maintains "cache coherency." A dual processor 91 series system has a cache size of 64 Kbytes per processor. For the quad 91 Series system, the cache is 32 Kbytes per processor. In each case, half the cache is used for data and half for instruction.

The Motorola 88000 family has two 2 gigabyte dual-mapped logical address spaces.  One 2 gigabyte area is user space and the other is system (operating system) space.  This segregates user application code from the co-resident operating systems.

Operating Systems
Encore 91 series systems utilize AT&T's V.3.2 UNIX as their base for real-time program development.  The operating system has been enhanced to support Encore 91 series' multiprocessing uniform memory architecture and multithreaded programming techniques.  The resulting symmetrical operating system implementation is known as UMAX V. In addition, extensions have been made to UMAX V to support the real-time operating systems, MicroMPX. Real-time applications developed using UMAX V facilities will execute on the Encore 91 series under the control of MicroMPX.

MicroMPX has been derived from Encore’sMPX-32 real-time operating system, a product proven and field tested with Encore’s CONCEPT 32 systems that have been shipping for over ten years into some of the world’s most time-critical applications. MicroMPX has been designed to be compatible with MPX-32 at the high-level language programmatic interface level. Specifically, current MPX-32 based applications, designed using Encore’s FORTRAN 77+, may be ported to the 91 series by recompiling and relinking for execution under control of MicroMPX. MicroMPX has been designed to conform to real-time standards including POSIX.

With the Encore 91 series, real-time applications are developed using UMAX V and all the standard UNIX facilities and services. The resulting program executes under the control of MicroMPX. MicroMPX supports fast, priority based, fully re-emptive scheduling with isolation from UNIX scheduling and system overhead. In addition MicroMPX services interrupts directly, as well as real-time I/O, without involvement of UMAX V. MicroMPX includes a UNIX-compatible file system which is enhanced to support contiguous and pre-allocated data files, crucial to real-time applications.

The role of UMAX V for the Encore 91 series is to provide a highly productive software development

environment while MicroMPX provides the high-performance real-time execution environment. Of the lour processors available on an Encore 91 series system, at least one must be devoted to UMAX V. The other processors can execute under control of UMAX V or real-time MicroMPX, depending on environmental needs. The user can dynamically reconfigure the processors between UMAX V and MicroMPX when his needs change. System administration and the console functions are handled by UMAX V, as is intersystem communications and the overall scheduling of the other processors. However, once a processor is running MicroMPX, UNIX can not gain control of the processor until MicroMPX relinquishes control.

Main Shared Memory
The minimum memory configuration for an Encore 91 series system is 16 megabytes. This shared memory is packaged on the same board as the central processors and utilizes one megabit DRAMs. All processors have uniform access to the shared memory. Data integrity is ensured by the inclusion of one parity bit for each byte in memory Four expansion memory cards can he added to 91 series systems, in 16 or 64 megabyte increments. Two or more expansion memory cards permit interleaved access to memory. The interleaving speeds up access time to memory, thereby boosting throughput of the overall system. The Encore 91 series memory can be expanded up to a total capacity of 272 megabytes if four 64 megabyte expansion memory cards are used. Expansion memory has identical access characteristics to local memory and in addition is dual ported to support simultaneous CPU and I/O accesses to main memory without contention.

Bus Structure
The Encore 91 series has several internal and external buses. The heart of the system is the internal high-speed 100 megabytes per second Local Bus. The processors and shared memory communicate over Local Bus. There are two principal industry-standard external buses available to 91 series users the SCSI bus and the VME bus. The two SCSI buses are used as peripheral buses for 91 series’ disks and tapes. The VME bus also is generated from a Local Bus interface on the Processor Board. The 91 series supports the VME-61 extension to the industry standard VME 32-bit bus. This extension allows block mode transfers to take place at sustained speeds in excess of 55 megabytes per second (peak rate of 80 megabytes), yet retaining compatibility with the industry standard VME 32-bit bus.

The Encore 91 series architecture has been designed such that the shared memory is dual ported. One port communicates with the central processors and the other directly with the VME bus. This means that I/O operations on the VME bus can make data transfers directly into shared main memory. It also means that because processor to memory data transfers use Local Bus, they do not place a load on the VME bus.

Real-Time Interfaces
Available as a VME—based option with the Encore 91 series is a 32-hit parallel High-Speed Data (HSD) interface. Encore’s HSD is the industry be facto standard for high—speed data input arid output. The HSD is typically used to interconnect two systems back—to—back or to act as an interlace to digital instrumentation, graphical devices or customer designed devices. The HSD provides a 32-hit wide, hall-duplex, point-to-point connection. The hardware is a board that can be inserted into a spare VME slot in the card cage. Appropriate software drivers are supplied.

Also available is a Reflective Memory System (RATS) interface. RMS is used to create a shared—memory multiprocessor system for two or more discrete systems. Each Encore 91 series system is a tightly coupled multiprocessor as it has two or four processors per cluster. However, RMS interfaces two or more 91 series systems to a common memory. Up to nine systems can he interconnected using Reflective Memory. Also, RMS can he used to interconnect the 91 series and Encores CONCEPT/32 line of high performance real-time systems.

There are two basic packages for an Encore 91 series system. For smaller configurations and for systems that reside in an office environment, the 91 series is available in a desk-high cabinet, 30 inches tall. It is on casters and can be powered from a standard 15-amp wall outlet. For shop floor and laboratory use, the 91 series can he installed in a cabinet that conforms to the 19-inch RETMA rail standard. The mid-size cabinet will hold one 91 series system and the full-height cabinet can have two complete 91 series clusters installed. The Encore 91 series systems are modular in that customers have great flexibility in con figuring their peripherals, communications and real-time options. The desk-high 91 series has a nine-slot VME card cage with one slot dedicated to the Processor Board. Desk-high 91 series systems have space for three

Peripherals - disks or cartridge tape transports. Encore 91 series systems configured in cabinets have 21 - slot VME card cages with the same slot dedicated to the processor hoard. The mid-height cabinet has one card cage and space for four standard form-factor peripherals. The full -height cabinet can he configured with two VME card cages and eight standard form—factor peripherals.

Available on Encores 91 series systems is a wide selection of industry-standard communications. The Processor Board has four asynchronous ports. Two are reserved for use by the operator’s console and a remote diagnostic port. The principal communication connection to 91 series systems is over Ethernet. The Processor Board includes a standard Ethernet (IEEE 802.3) port. User terminals may interface to a 91 series system via an Encore supplied Annex terminal server (or equivalent) that also resides on the Ethernet local area network. Terminal users communicate with the Encore 91 series system using standard TCP/IP protocols and applications such as "telnet" and rlogin." Users will also have the use of other TCP/IP application such as file transfer and mail.

For wide area communications, the 91 series includes, as an option, a VME-based synchronous board that supports the X.25 protocol. This option allows the 91 series to communicate with other systems using packet data networks (PDNs) such as Telenet, Tymnet, Datapac, etc.

Also available on the Encore 91 series is the Network File System (NFS) developed by Sun Microsystems Inc. This allows 91 series users to access files on remote systems. The 91 series can act as an NFS Server (to provide files to others) or as a Client (to use files, which reside on other systems). NFS is a protocol that utilizes the standard Ethernet port provided with the 91 series.

Network software built over standard protocols will also be developed to work over Reflective Memory, thereby providing the functionality of Reflective Memory software for large-scale multiprocessor configurations.

The Encore 91 series has adopted a standardized approach for a basic set of disks and tapes. The Processor Board has two SCSI ports — one single ended and one differential. The former is normally used for Peripherals that reside within the processor cabinet. Differential allows longer cable distances and is useful when the SCSI bus must he routed between cabinets. Synchronous or asynchronous SCSI protocols are supported on either port and can he intermixed on each SCSI bus. However, synchronous protocols provide a performance advantage over asynchronous protocols. Both the desk-high 91 series and the cabinet versions use the industry standard 5.25-inch form factor peripherals. These include 300 and 600-megabyte disks and a 320-megabyte cartridge tape drive. The tape drive uses the industry defined QIC tape formats. Specifically, QIC-320, -150 and -120 formats can be written and read. Tapes recorded to the older QIC-24 standard can be read.

The disks and tapes referred to above are housed in Encore designed enclosures that allow easy insertion into mailboxes mounted in 91 series mid-size and full height cabinets. SCSI peripherals can be removed from the system wit hour dropping main processor power. In the case of disks, this feature allows users to remove their private data for secure storage.

As an alternative for tape storage, a standard nine-track tri-density tape transport is available. This is a 125ips transport with front loading access. The tape transport may be mounted in the processor cabinet or in a peripheral cabinet. Encore 91 series systems in desk-height cabinets can use a tabletop nine-track tape transport.

Encore can supply several printers for use with Encore 91 series systems. These can be laser technology page printers or impact printers with parallel or serial interfaces. The Annex terminal server has a parallel port for use by printers In addition, serial printers can be attached to the asynchronous ports on the Processor Board or to the asynchronous ports on the Annex terminal server.

There are two choices for an operator’s console. The entry-level device utilizes a low functionality terminal on one of the asynchronous ports on the Processor Board. Control of multiple networked 9) series systems, from one device, may use a personal computer with a direct attachment to Ethernet. This option pro-vides for window capability to monitor and control multiple 91 series nodes concurrently.

Compilers and Tools
The Encore 91 series system is available with FORTRAN, C and Ada compilers. These compilers are hosted by UMAX V. System calls to other language are permitted from each compiler environment. All Encore high-level languages have advanced, highly optimizing code generators that greatly improve on the run time speed and compactness of earlier programming language systems.

The Encore 91 series FORTRAN is available in two versions: The sequential version creates programs that conventially execute on a single processor. The parallel version creates programs that allow parts of the application to execute on more than one processor at a time. This parallelization can be user directed, automatic, or a combination of both. The parallelization of an application to use multiple processors will give an application a distinct performance boost at run time. The FORTRAN supplied with Encore 91 series systems (ANSI FORTRAN 77) is compatible with the functions and real-time extensions of FORTRAN 77+ available with Encore s CONCEPT 32 systems.

Encore was the first company to offer a validated Parallel Ada compiler. This tradition continues with Parallel Ada availability on the Encore 91 In addition, Encores Micro ARTE (Ada Real-Time Executive) provides a low overhead approach to maximize real-time Ada performance.

Through the use of Ada tasking, the Encore 91 series Ada also allows the user to easily develop applications that execute on more than one processor at a time. The user can modify the number of processors used, depending, for example, on whether code is being debugged or delivered code is running.

All Encore 91 languages also provide access to MicroMPX services. Through these services, the user can develop multi-tasking applications that use multiple processors.

Case Environment
Encore 91’s UNIX and MicroMPX domains provide a complete multi-language-programming environment supplemented by workstation and X-windows-based Upper and Lower CASE tools. The UNIX CASE suite will include support for cost estimation, project management, requirements analysis, structured analysis, structured design, configuration management, software repositories and document publishing.

Motif-based non-intrusive parallel instrumentation (Parasight) software will be integrated as part of the CASE offering. Parasights ability to control and monitor tasks, as well as access memory in a non-intrusive fashion, sets the standard for debugging and tuning large real-time systems. Encore is committed to providing a highly productive CASE environment to reduce our customers software development and maintenance costs.

Product Specifications Processor


25 MHz Motorola 88100 32-bit RISC.
Symmetric multiprocessor.
2 or 4 processors per 9LJ card.
Integrated IEEE 754 floating point.

Motorola 88200 cache/memory management unit.
32 Kbytes cache per quad processor — 16Kb data,16Kb instructions.
4 Gigabyte address space — 2Gb user, 2Gb system.


16 Mb on processor hoard — single port access.
Expansion cards, 16 or 64 Mb each. Up to four can be added.
Expansion memory is dual-port access with interleaving.
Total memory capacity of 272 Mb.


VME revision C.1 32-bit bus (VME-32).
VME-64 extensions to VME-32 for 64-hit block mode transfers.
SCSI — single ended and differential — asynchronous or synchronous.
Internal Local Bus — 100 Mb/sec.

Software Environment

Power Domain multi-operating system architecture.
MicroMPX deterministic real-time execution operating system.
UMAX V for software development and high level control of MicroMPX.
88/OPEN BCS application software conformance.

Real-Time Features

24 hardware maskable interrupts.
Seven programmable counters.
Real-time clock.
HSD Interface for high speed data input and output.
Reflective Memory (RMS) — high speed shared memory link. Tri-ported design.

Languages and Tools

FORTRAN 77 for creation of sequential or parallel code.
Compatibility with FORTRAN 77+ on CONCEPT/32 systems.
C compiler — packaged with UMAX V.
Ada - Parallel Ada and Micro ARTE (Ada Real-Time Executive).Parasighi debugger and monitor for parallel programs non-intrusive for real- time applications.
CASE tools -  to enhance the software development process.


Ethernet (IEEE 802.3) port standard. 
Four RS232-C asynchronous lines standard
TCP/ IP and NFS optional.
X.25 (hardware and software) optional.
Wide selection of VME boards available - additional
Ethernet ports, more asynchronous lines etc.


SCSI 5.25-inch disks — 300 and 600 megabytes.
SCSI 5.25-inch cartridge tape — 320 Mb storage.
Nine track tri-density tape.
Impact and non-impact printers.
Ethernet-based Annex Terminal Server.
Terminals and personal computers.


Desk-high cabinet, single node, 30 inches tall.
Nine-slot VME 9U chassis — up to eight slots available for peripheral expansion.
One or two SCSI 5.25-inch peripherals.
Power: H5./220 volts, 50/60 Hz. 15 amps single phase at 115 volts

Mid-size cabinet for single node.
Matching peripheral cabinet for expansion.
21-slot VME 9U card cage up to 20 slots available for options.
Up to four SCSI peripherals.
Power — 220 volts, 50/60 Hz single phase, 50A. 
Size — 33 inches wide, 18 inches deep, 53 inches tall.

Full-height cabinet for dual node.
Matching peripheral cabinet for expansion.
Dual 21-slot VME 91J card cages — up to 20 slots available per cage for options.
Up to eight SCSI peripherals.
Power — 220 volts, 50/60 Hz single phase. 50A.
Size — 33 inches wide. 38 inches deep, 78 inches tall.


Temperature: ID to 40 degrees Centigrade. operational.
Humidity: 20% to 80% non—condensing operational.
Certified to comply with applicable FCC, UL, CSA and VDE standards.


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