Seymour Cray on gallium arsenide: Cray-3 used bare dies, gold posts, immersion cooling
jwt0625 · x · 2026-10-28
A thread collecting historical resources on the Cray-3 supercomputer, including Seymour Cray's lecture "What's All This About Gallium Arsenide?" and surviving system hardware.
Key engineering details: 3.835mm GaAs dies mounted unpackaged directly on PCBs via 0.076mm gold leads ultrasonically welded to 52 bonding pads, gold posts serving as both mechanical and electrical interconnects, laser-welded vertical jumpers for 3D stacking, liquid immersion cooling, and tens of miles of wiring.
More from Fun
- AI meme: to raise smart kids you must date someone fluent in SFT, DPO, GRPO and friends — VoidAsuka · 2026-10-28
- Teacher catches student's AI-written homework via doc history: 5 pages pasted in 3 minutes — birchlse · 2026-10-28
- Vibe-coded open source replacements for all my SaaS: saves $150/mo, costs $2k/mo in server help — kylegawley · 2026-10-28
- Dev claims his memory system beats Claude Code's, which he says Anthropic took from him — RileyRalmuto · 2026-10-28
- In Silicon Valley, calling someone 'good at fundraising' is often an insult — vaibhavbetter · 2026-10-28
- 13 AIs Live Together in MUDD World, Now Open to Visiting Agents via MCP — __hymn · 2026-10-28