Alliant Computer Systems
| Company type | Private |
|---|---|
| Industry | Computer hardware, Parallel computing |
| Predecessor | Dataflow Systems |
| Founded | May 1982 |
| Founder | Ron Gruner, Craig Mundie, Rich McAndrew |
| Defunct | 1992 |
| Fate | Bankruptcy |
| Headquarters | United States |
Area served | Worldwide |
| Products | Parallel computing hardware (FX series, FX/2800 series, CAMPUS/800) |
Alliant Computer Systems Corporation was a technology firm focused on the creation and production of parallel computing hardware. Together with companies like Pyramid Technology and Sequent Computer Systems, Alliant played a key role in establishing the symmetric multiprocessing industry. Having manufactured more than 650 units, it ranked among the leading companies in this field before encountering financial setbacks that led to bankruptcy in 1992.
1980s
Originally established as Dataflow Systems in May 1982 by Ron Gruner, Craig Mundie, and Rich McAndrew, Alliant aimed at scientific and engineering professionals who required smaller, cost-effective alternatives to premium suppliers such as Cray Computer. This market segment later became recognized as the minisupercomputer category. During that period, a notable price-to-performance disparity existed between machines like the VAX 11/780—offering approximately 1 MIP and MegaFLOP for $1 million—and Cray systems priced above $10 million.
The company’s initial lineup, the FX series released in 1985, consisted of four distinct 18" x 18" circuit boards: Computational Elements (CEs), System Cache, Interactive Processor (IP) Cache, and Memory Modules. These components interconnected through an active backplane featuring an 8 x 4 crossbar switch, facilitating a high cache bandwidth of 376 MB/s. The CEs integrated Weitek 1064/1065 floating-point units with custom vector processors based on a Motorola 68000 scalar instruction set complemented by proprietary co-processor instructions for floating-point, vector, and parallel operations. A low-latency concurrency bus enabled efficient data-parallel processing optimized by advanced compiler technologies. The scalar processor operated with a cycle time of 170 ns, while vector processing achieved twice that speed at 85 ns.
Interactive Processors utilized Motorola CPUs starting with the 68012 and advancing to the 68020 and 68030 models, each equipped with 4 MB of local memory on Multibus cards. Memory modules were configured as 8 MB units with four-way interleaving and ECC protection, providing a read bandwidth of 188 MB/s.
The FX series operated on a tailored version of 4.2 BSD Unix named Concentrix, which incorporated features such as multiprocessing support, enhanced virtual memory management, advanced I/O systems, a striped Track File System (TFS), and real-time scheduling capabilities (FX/RT). The product range included FX/1, FX/4, and FX/8 models distinguished by their maximum number of CEs. The FX/1 delivered performance near 2.5 MIPS—surpassing the VAX-11/780's approximate 1 MIPS—while the FX/8 could achieve up to fivefold improvements on tasks amenable to parallelization.
In early 1988, Alliant unveiled the Advanced Computational Element (ACE), which replaced the CE with a pin-compatible module incorporating Bipolar Integrated Technology floating-point chips and an updated vector processor featuring expanded registers and a reduced cycle time of 42 ns. Systems based on ACE included the FX/40, FX/80, and VFX models. Existing FX/4 and FX/8 machines were upgradeable by exchanging CEs for ACEs alongside microcode updates; however, mixed configurations were not supported. The smaller FX/1 model could not be upgraded due to thermal constraints.
Additionally, Alliant developed complementary software such as the FX/Skyline Solver designed for linear equation solutions, the FX/C compiler, and scientific libraries including FX/Linpack and FX/Eispack to enhance compatibility with their hardware platforms.
1990s
In 1990, the FX/2800 series succeeded the CE/ACEs and IPs by introducing modules built around the Intel i860 RISC processor, one of the earliest superscalar CPUs providing direct pipeline access. Leveraging specialized programming, the i860 delivered exceptional speed suited for supercomputer tasks. The Super Computational Element (SCE) and Super Interactive Processor (SIP) each contained up to four i860 processors, with a crossbar interconnecting as many as seven units, allowing a fully configured FX/2800 to operate with 28 i860 chips.
In July 1988, Alliant acquired Raster Technologies, a company specializing in high-resolution graphics terminals and custom expansion cards for Sun Microsystems workstations. Their GX4000 system integrated PHIGS+ software with dedicated graphics hardware designed for rapid vector rendering and display, incorporating hardware-based Z-buffering to enhance 3D visualization. This graphical technology was incorporated into the FX/40 and FX/80 systems, creating the VFX—the first fully integrated graphical minisupercomputer produced by Alliant.
The CAMPUS/800 represented Alliant’s final product line, featuring a massively parallel architecture composed of ClusterNodes similar to FX/2800 units that shared up to 4GB of unified memory. Each ClusterNode could connect with as many as 32 others through an intra-ClusterNode switch offering 1 μs latency and 1.12 GB/s throughput; an inter-ClusterNode HIPPI switch provided 30 μs latency and bandwidth of 2.56 GB/s. The most extensive CAMPUS configuration included 192 ClusterNodes, achieving a peak performance of 4.7 GFLOPS.
Introduced in 1991, the CAMPUS/800 was released during a period of financial difficulty for Alliant, culminating in bankruptcy in 1992. Nonetheless, numerous Alliant systems continued to operate reliably for many years following.
Alliant played a role in advancing High Performance Fortran, demonstrating its impact on evolving industry standards.
The Computer History Museum preserves examples of the FX/8 and FX/1 (the latter originating from Convex Computer Corporation after acquiring Alliant), while actively seeking to acquire FX/80 and FX/2800 models.