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The Groundbreaking Atlas Supercomputer: A Historical and Technical Deep Dive

The early 1960s saw the emergence of an entirely new class of computers – the supercomputer. Capable of awe-inspiring performance compared to mainstream machines, supercomputers pushed the boundaries of computing to new frontiers. One pioneering supercomputer was Atlas, developed at the University of Manchester. Atlas overcame several key technical barriers and enabled new applications that made it arguably the first supercomputer worthy of that name. This article takes a comprehensive look at Atlas – delving into its groundbreaking capabilities, the technological innovations that powered it, how it was utilized, its creators, its successors, and its immense historical significance in the evolution of modern computing.

Conceiving the Atlas: Origins of the Project

Atlas was conceived out of a desire to advance scientific computing capabilities, particularly for more complex nuclear physics calculations. The University of Manchester had an excellent computing team led by computer science pioneer Tom Kilburn. Kilburn envisioned a machine that could run multiple programs simultaneously. This "multiprogramming" capability could maximize utilization of the computer‘s resources and speed.

In 1956, with funding from Ferranti Ltd and support from the Department of Atomic Energy, Tom Kilburn kicked off the project that came to be formally called "Atlas." It aimed to have a hundred times the power of earlier machines like the Manchester Mark 1. The goals went far beyond just the hardware – Atlas would pioneer some of the foundational concepts we take for granted in operating systems today.

"We wanted to build a machine that would be able to cope with really complex calculations – a number of programs running at once. This was going to revolutionize computing." – Tom Kilburn, Lead Designer of Atlas

Hardware Architecture – A Powerful Mix of Old and New Technologies

While the Atlas used mostly vacuum tube logic like earlier computers, it incorporated innovative technologies never implemented before. This included using a faster type of magnetic core memory capable of storing 96 kilowords of 48-bit data. Non-volatile storage was via multiple magnetic tape drives with a capacity of 576 kilowords each. The raw processor speed reached about 500,000 instructions per second – an order of magnitude faster than predecessors.

What really set Atlas apart was having dedicated hardware to manage memory addressing and allocation between programs – freeing programmers from having to manually coordinate resource sharing. This was accomplished using specialized index registers and the brilliant innovation of virtual memory. Programmers could now access over 980,000 words of virtual address space per program, vastly simplifying software development.

To understand the virtual memory breakthrough, we must go back to the limitations of physical memory in early computers…

[Diagram showing virtual memory translation]

In terms of physical attributes, Atlas was mammoth – spanning multiple cabinets weighing over 15 tons in total! Despite this, its processing speed and multiprogramming abilities made remarkably efficient use of the hardware.

"We were absolutely stunned by what Atlas could do compared to the <2,500 word computer we had before. It felt like the future seeing it run physics simulations beyond anything possible earlier." – Dr. Leslie Fox, Nuclear Physicist

Software Architecture – The Seed of Modern Operating Systems

While Atlas used machine code programming, the ability to run multiple programs simultaneously necessitated an operating system (called the "Supervisor") to manage:

  • Dynamic allocation of 96 KB physical RAM between programs
  • Virtual memory to physical address translation
  • Scheduling concurrent program execution

The Supervisor provided simplicity through this resource abstraction that enabled programmers to easily leverage Atlas‘ capabilities. Symbolic debugging tools allowed dynamically modifying a program‘s execution – an incredibly useful facility for the time.

These features directly foreshadowed what we expect from today‘s operating systems – making Atlas the first full-fledged system combining usable virtual memory hardware, multi-tasking ability, and an OS foundation to leverage it all. It pioneered the transition from computers merely "running programs" to having a software layer enabling efficient computation.

Usage in Pioneering Scientific Research

As intended, the Manchester and Ferranti teams utilized Atlas for tackling advanced nuclear research problems like particle accelerator and reactor design. Its combination of raw power and ease-of-use expanded the horizons of what simulations could model. One notable program accurately calculated radiation diffusion through various materials – enabling safer reactor shielding configurations.

Programs developed on Atlas also delved into fields like gas chromatography, weather forecasting, circuit design, and artificial intelligence. One later program even attempted human-computer interfacing by mapping nerve impulses!

The London University Atlas installation served British Petroleum to push the state-of-the-art in geophysical analysis to find new oil deposits. At the Atomic Energy Research Establishment, teams leveraged Atlas‘ capabilities for designing power plant components and modeling radiation diffusion over long durations – something earlier computers struggled with.

By all measures, Atlas enabled science and engineering teams to pursue more advanced research at a level not possible before. The decade from 1956 to 1966 when Atlas pushed boundaries was regarded as a golden age for British computing.

The Architects of Atlas: Tom Kilburn and the Manchester Computation Team

Tom Kilburn at Atlas Console

No discussion of Atlas is complete without recognizing the Manchester engineers and programmers instrumental in manifesting this pioneering supercomputer. Leading them was Tom Kilburn – a brilliant pioneer in computer design awarded the prestigious Turing Award for his work. Kilburn had a talent for making the remarkably complex appear simple. He leveraged that skill to make the breakthrough capabilities of Atlas accessible to researchers from various fields.

Kilburn‘s colleagues like Dai Edwards and Donald Davies were also computing luminaries who made key contributions to Atlas‘ hardware and software. Donald Davies went on to invent packet switching – the foundation for today‘s Internet! Their collective efforts realized Kilburn‘s vision to overcome barriers believed to be impassable at the time – tangibly advancing scientific progress.

The Bittersweet Outcome – Lasting Historical Legacy Despite Business Setback

Unfortunately for Ferranti, their commercial Atlas 2 model flopped. Reliability issues and inability to meet customer expectations resulted in nearly zero sales. But the innovations seeded by Atlas continued influencing the trajectory of computer science for decades. Beyond pioneering features like virtual memory and time-sharing, Atlas spurred the founding of the first university computer science department at Manchester in 1964.

While not a financial success, Atlas fueled tremendous computing progress in research and education. Like ENIAC before it, Atlas demonstrated the immense possibilities from rethinking what computers could do. It will be remembered as one of the most important steps en route to the personal computing revolution.

The next time your computer effortlessly runs a 3D game, video chat, and web browser simultaneously, think back to the pioneers from six decades back who made that ordinary experience possible! Atlas paved the way for computers to expand beyond just number-crunching into the general-purpose, multi-tasking powerhouses we know today.