Connection Machine

Thinking Machines Corporation
Company type	Private
Industry	Computer hardware, Supercomputing
Founded	1983 in Waltham, Massachusetts, United States
Founder	Danny Hillis, Sheryl Handler
Headquarters	Cambridge, Massachusetts, United States
Products	Connection Machine series (CM-1, CM-2, CM-2a, CM-200, CM-5, CM-5E)

The Connection Machine (CM) represents a line of massively parallel supercomputers created by Thinking Machines Corporation. Originating from Danny Hillis's doctoral work at MIT during the early 1980s, the Connection Machine was engineered to move beyond conventional von Neumann architecture by utilizing thousands of microprocessors simultaneously. While its initial focus was on artificial intelligence and symbolic computation, later iterations found significant application within computational science.

Origin of idea

In 1983, Danny Hillis and Sheryl Handler established Thinking Machines Corporation in Waltham, Massachusetts, before relocating the company to Cambridge, MA in 1984. Hillis spearheaded the creation of the CM-1, which featured a massively parallel hypercube configuration encompassing thousands of microprocessors. This design was grounded in his 1985 MIT PhD dissertation in Electrical Engineering and Computer Science. His thesis—recipient of the ACM Distinguished Dissertation award—outlined the system’s architecture, mechanisms for data routing and memory management, as well as the application of Lisp programming for parallel computing. The original concept anticipated scaling up to over one million processors interconnected via a 20-dimensional hypercube, although this ambition was eventually moderated.

Designs

Thinking Machines Connection Machine models
	1984	1985	1986	1987	1988	1989	1990	1991		1992	1993	1994
	Custom architecture								RISC-based (SPARC)
Entry	—				CM-2a				—
Mainstream	—	CM-1		CM-2			—		CM-5		CM-5E
Hi-end	—				CM-200				CM-5		CM-5E
expansions
Storage	—			DataVault						—

Each processor within the CM-1 contains 4 kilobits of memory and is interconnected through a 12-dimensional hypercube network supporting up to 65,536 elementary 1-bit processors performing SIMD tasks. Both the CM-1 and its successor, the CM-2, are cubic in shape (approximately 1.5 m per side), segmented into eight subcubes. Each subcube holds sixteen circuit boards equipped with routers, processors, and memory modules. The architecture incorporates a principal RAM alongside an input-output processor. Individual chips link to a central switching node; routers include five buffers inspired by Richard Feynman’s theoretical work, optimizing both chip dimensions and operational efficiency. The CM-1 employs Feynman’s logarithmic algorithm, facilitating high-speed calculations such as those required in quantum chromodynamics (QCD), outperforming dedicated specialized hardware.

To boost market viability, the 1987 CM-2 introduced Weitek 3132 floating-point coprocessors shared among clusters of processors and expanded memory capacity up to 512 MB. It also debuted the DataVault RAID storage system capable of holding up to 25 GB. Variants encompassed the smaller-scale CM-2a with either 4,096 or 8,192 processors and the enhanced-performance CM-200.

Rooted in artificial intelligence origins, early software development utilized Lisp dialects such as *Lisp on the CM-1*, with system-level tools crafted in *Lisp* and many applications implemented using C*, a data-parallel ANSI C extension.

The release of the CM-5 in 1991 marked a pivotal transition from SIMD hypercube configurations to a MIMD design based on a fat-tree network architecture employing RISC SPARC processors. This design simulated SIMD execution to simplify programming complexity. The upgraded CM-5E featured SuperSPARC CPUs. In 1993, the CM-5 attained top ranking on the TOP500 list by delivering peak performance of 131.0 Gflops across 1024 cores and remained among the leading supercomputers for several subsequent years.

Visual design

The Connection Machines stood out due to their unique aesthetic. The design teams for the CM-1 and CM-2 were headed by Tamiko Thiel. The chassis for the CM-1, CM-2, and CM-200 adopted a cube-of-cubes structure, symbolizing the machine's 12-dimensional hypercube network topology. Each cube’s doors revealed red light-emitting diode (LED) indicators that displayed the operational status of individual processors.

Typically, an LED illuminated when its corresponding processor was executing an instruction. In SIMD applications, peak efficiency was achieved when numerous processors operated concurrently, resulting in a steady glow of LEDs. Some users preferred dynamic LED effects such as blinking or displaying messages, prompting software to include additional instructions solely to manipulate these lights.

The CM-5 featured a distinctive stepped configuration complemented by large panels of blinking red LEDs. The design benefited from the artistic input of sculptor and architect Maya Lin.

Permanent exhibits

The inaugural CM-1 is permanently showcased at the Computer History Museum in Mountain View, California, which also maintains several other CM-1 units and a CM-5.
At the Karlsruhe Institute of Technology’s computer science department, a retired CM-1 or CM-2 is on display and has been modified by students into a Bluetooth-enabled LED matrix for games and artistic purposes.
A CM-2 equipped with flashing red LEDs alongside its DataVault storage system is a permanent fixture at the Mimms Museum of Technology and Art located in Roswell, Georgia.
A CM-200 is part of the exhibition at the École Polytechnique Fédérale de Lausanne in Switzerland within the Musée Bolo gallery.

Past exhibits and museum collections

In 2018, the Museum of Modern Art in New York City exhibited a CM-2 and continues to retain it within their collection.
The Swedish National Museum of Science and Technology (Tekniska Museet) in Stockholm holds a CM-2 in its collection.
Although not complete, several components of a CM-1 are preserved by the Smithsonian Institution’s National Museum of American History.
Prior to its closure in 2020, the Living Computers: Museum + Labs in Seattle displayed a CM-2 with active flashing LEDs. This unit may have transitioned into private ownership but was not listed in Christie's auction.

Private collections

As reported in 2007, the Corestore—an online-only museum—possessed a preserved CM-2a.

References in popular culture

A CM-5 appeared on screen in Jurassic Park within the island’s control room, replacing the Cray X-MP supercomputer depicted in Michael Crichton’s novel. The visible setup included two banks: one containing four units and another single unit positioned separately to the right.

The design of mainframes featured in Fallout 3 was heavily influenced by the CM-5’s appearance.

Multiple units resembling the CM-1/CM-2 style are present throughout the environments in Cyberpunk 2077.

The b-side track to Clock DVA's 1989 single "The Hacker" is entitled "The Connection Machine," paying homage to the CM-1.

External links