Many exotic computing solutions have been proposed, such as optical computing [1], reversible computing [2], computing using the native physics of materials [3], and computing using thermodynamics itself [4]. However, their extended time horizons and risks are problematic for venture investment. At the same time, ventures targeting near-term computing products based on the same CMOS and memory technology in mainstream use today will be very challenged in meaningfully differentiating themselves from those produced by large and powerful incumbents.

Both are compromised from a venture investment perspective- is there a middle way?

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Geoff Hinton coined the term Mortal Computing in 2022, speaking of a software program evolved to run on one specific instance of a hardware device, which he suggests would be composed of extremely efficient but not entirely reliable computing elements, and that this might be the only means of being able to realize practical computing devices based on revolutionary device technology. See his presentation on Youtube.

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This note explores the concept of Mortal Computing and finds that while the development of radically novel or unreliable computing technology is certainly one application for it, it is also broadly applicable to a spectrum of near-term computing innovation and therefore a candidate for new Deeptech ventures with a wide range of time horizons, strong differentiation against the prevailing computing paradigm, and long-term potential.

Immortal Computing

To properly define Mortal Computing, it is first necessary to define its ancestor, Immortal Computing - which is intentionally shackled by the following two constraints (of which the latter is by far the stronger one).

• Deterministic: A given program must produce Identical results with Deterministic Precision and Predictable Performance when run multiple times on the same device.
• Fungible: A given program satisfies the Deterministic Precision and Predictable Performance conditions when run on multiple devices of the same type and satisfies just the Deterministic Precision condition when run on different devices with compatible instruction set.

It is immediately apparent that the immortal component is the program and not the hardware - all physical things have finite lifetimes - but software that can be stored indefinitely and run anywhere is truly immortal.

The core design mechanisms of Immortal Computers are:

• Zero Defects: The part is offered for sale based on having no user visible defects, achieved via thorough testing and redundant hardware.
• Design Margin: Manufacturing and environmental variability is addressed via careful margining at design time plus assumptions/limits on range of variability.
• Static Compensation: Variability is further addressed by simple static settings for deployment, such as running fast and energy hungry parts at a lower voltage than slow and lower energy parts.
• Simple Automatic Adaptation: Basic control loops adjust just one or two system variables dynamically to keep operation within spec. Dynamic voltage and frequency scaling is a primary example.

These solutions generally outperform the spec sheet under almost all conditions, but this additional performance is not usable or monetised. As transistors shrink and advanced packaging introduces an array of challenges around thermal management, defectivity and cost, this over-margining becomes increasingly onerous. At the very same time, existing systems like large scale super computers [5], advanced robots operating in complex environments [6,7] or products that employ AI using lifetime learning [8] are already facing challenges in maintaining the determinism and fungibility demanded by the Immortal Computing paradigm.

Rather than seeing Hinton's Mortal Computing concept as being limited to development of future novel circuit structures, this article seeks to develop a broader and more widely applicable definition suitable for near term investment.

Weakly Immortal Computing

Some first steps towards Mortal Computing are present in existing mainstream devices, already eroding long-held assumptions about what attributes computers should and should not embody.