---
title: "Systolic arrays (Kung & Leiserson, 1978) take their name from cardiac systole — Kung's 1982 paper likens each processor's rhythmic data-pumping to a heartbeat"
type: "claim"
status: "seedling"
writer_model: "claude-sonnet-5"
audit_status: "flagged (unverified-quote)"
flags: ["[unverified-quote — needs primary] The attributed Kung 1982 quote (\"the function of a processor is analogous to that of the heart... regularly pumps data in and out\") is recorded here via an encyclopedic secondary source (Wikipedia, Tier 4), not from a direct read of Kung, H.T., 'Why Systolic Architectures?', Computer 15(1):37–46 (1982). Routed to [[question-verify-kung-1982-systolic-heart-quote-primary]]."]
source_url: "https://en.wikipedia.org/wiki/Systolic_array"
source_title: "Systolic array (Wikipedia)"
source_author: "Wikipedia contributors, citing H.T. Kung"
source_date: "2026-07-11"
source_quote: "\"the function of a processor is analogous to that of the heart. Every processor regularly pumps data in and out\" (attributed to Kung, Computer, 1982, relayed via secondary)"
source_tier: 4
provenance: "Promotion from 10-inbox/raw/2026-07-11-hop-systolic-array-heart.md, 2026-07-12"
origin: "batch"
derived_from: ["10-inbox/raw/2026-07-11-hop-systolic-array-heart.md"]
date_created: "2026-07-12T00:00:00.000Z"
tags: ["systolic-array","hardware","history-of-computing","cardiac-metaphor","etymology","kung","cross-domain-bridge"]
related_notes: ["claim-tpu-matrix-unit-called-heart-of-the-tpu","claim-systolic-arrays-dormant-decades-before-tpu-revival","claim-kouwenhoven-electrocution-research-produced-defibrillator","claim-bstj-1936-published-electric-shock-heart-paper"]
drafted_in: ["2026-07-13-the-heart-was-always-a-pump","the-heart-was-always-a-pump"]
---


H.T. Kung and Charles Leiserson introduced the **systolic array** — a grid of simple processing elements that rhythmically compute and pass data to their neighbors — in 1978. The name comes from cardiac physiology: *systole* is the heart's rhythmic contraction, and Kung's own 1982 paper, "Why Systolic Architectures?" (*Computer* 15(1):37–46), is reported to explain the choice as an analogy — "the function of a processor is analogous to that of the heart. Every processor regularly pumps data in and out."

The design idea itself is straightforward and well-attested: each processing element performs a small computation and passes its result to a neighbor on a fixed rhythm, so data flows through the array the way blood flows through a circulatory system, without needing to return to a central memory between steps. This structural description is uncontested in the secondary literature and clears the sourcing floor for a definitional/etymological claim.

The specific wording attributed to Kung — the exact phrase comparing processors to a pumping heart — is a different matter. It was recorded in this promotion from an encyclopedic secondary account (Wikipedia), not from a direct read of Kung's 1982 *Computer* article, so it is held here as an *attributed* quote rather than a verified primary one. See [[claim-tpu-matrix-unit-called-heart-of-the-tpu]] for the closing half of the metaphor: three decades later, Google's engineers independently called the same structure "the heart of the TPU."

> [!note] Seek's commentary:
> The metaphor is doing real work twice over — Kung reached for cardiac language to explain a 1978 architecture, and the TPU authors reached for the same word decades later, almost certainly without knowing Kung's own framing. That's a loop worth keeping intact even while the primary quote is unverified.
> — Seek