Diff — CDC 6600

{{infobox

| title = CDC 6600

| designer = Seymour Cray / Control Data Corporation — Chippewa Falls lab

| released = September 1964 · ~$2.37M · 100+ sold

| cooling = Freon refrigerant — liquid-cooled before it was fashionable

| fame = the first supercomputer — ~10× the IBM 7090 it obsoleted

}}

# CDC 6600

The **CDC 6600** was built by a man who left town to build it. Seymour Cray, frustrated with corporate interference at Control Data's Minneapolis headquarters, decamped to a lab in **Chippewa Falls, Wisconsin**, and — with a team of just **34 people** — produced in 1964 a machine roughly **ten times faster** than the IBM 7090 that defined the previous era's peak. It was the first computer the industry called a **supercomputer**, and for five years there was no argument about which machine was the world's fastest.[[cite: [CDC 6600](https://en.wikipedia.org/wiki/CDC_6600) and the [bitsavers archive](https://bitsavers.org/pdf/cdc/) — the Chippewa Falls retreat, the team size, and the performance gap]]

The engineering was architectural minimalism taken to its extreme: a 60-bit central processor at 10 MHz with a **RISC-like, small instruction set**, cooled by circulating **Freon** refrigerant so the circuits could be packed tighter than air allowed. The key structural move was the **ten peripheral processors** — small dedicated machines that handled all I/O, leaving the central processor to do nothing but compute. The division of labor meant the 6600's CPU never waited on a card reader — the architecture that later every supercomputer and, eventually, every DMA engine and coprocessor would re-invent.[[cite: [CDC 6600 description](https://en.wikipedia.org/wiki/CDC_6600#Description) — the 10 PPUs, Freon cooling, and the RISC-like CP instruction set]]

# What it obsoleted

The 6600 made the previous generation's flagships look silly — IBM's own STRETCH project had just shipped the 7030, far slower and at far greater cost and team size. Cray's response to bureaucracy was thirty-four people and a drawing board; the result outperformed IBM's flagship programs by an order of magnitude and sold over a hundred units at $2.37 million each. The machine ran SCOPE and KRONOS — operating systems almost as legendarily difficult as the hardware was brilliant.[[cite: [CDC 6600](https://en.wikipedia.org/wiki/CDC_6600) — the IBM contrast, the sales figures, and the OS pair]]

```fact

The 6600's ten peripheral processors are the reason "supercomputer" exists as a word: the central processor never did I/O at all — it computed; the PPs did everything else. Cray had figured out, in 1964, that the fastest machine isn't the one that computes fastest — it's the one that never stops computing.

```

# Where it sits

The 6600 is the machine the supercomputer era starts with — and its design method (small team, remote lab, no compromise) became the Cray legend that produced the 7600, the Cray-1, and the entire vector-supercomputing genre. It also closed the loop Whirlwind opened: a machine so fast it made speed itself a product category.

## Check your understanding

- [ ] Who designed the 6600 — and where did he build it to escape corporate interference?

- [ ] What did the ten peripheral processors do?

- [ ] How much faster was it than the era's previous flagship?

- [ ] What cooling technology kept it dense enough to be fast?

```hide Show answers

1 — **Seymour Cray**, at a deliberately remote lab in **Chippewa Falls, Wisconsin**, with **34 people**.

2 — all the **I/O** — freeing the 60-bit central processor to do nothing but compute.

3 — about **10× the IBM 7090** — instantly creating the "supercomputer" category.

4 — **Freon refrigerant** — liquid cooling for tighter packing in 1964.

```

[[Category:Hardware]]

[[Category:Computing]]

[[Category:History]]