I need a compact, USB4-compliant USB-C switch that lets one external hard drive move seamlessly between two PCs. Rather than pressing a physical button, I want to trigger the changeover from a small software utility—CLI or lightweight GUI—that can run on LINUX and exposes a simple command for scripting. Key expectations • Full USB4 / 40 Gb s data integrity so the drive performs exactly as if it were plugged in directly. • Safe hand-off: the inactive PC must see the drive cleanly disconnected while the active PC gains it with no enumeration errors. • Power distribution handled internally, with over-current protection. • Latency from software click to successful hand-off under two seconds. Deliverables 1. Hardware schematic, PCB layout, and complete BOM using readily available parts. 2. Firmware for any on-board controller or mux used to manage the switching logic. 3. Cross-platform control software (source code + compiled Windows binary) that: – Lists current host ownership. – Allows switch command via GUI click or CLI call. 4. Assembly guidance and testing procedure. 5. Proof-of-concept video or log showing the hard drive moving between two live PCs. I’m happy to iterate on form-factor, but the first milestone is a working prototype that satisfies the data-rate and safe-disconnect requirements. If you have prior experience with USB4 retimers, PD negotiation, or similar high-speed switching designs, I’d love to see it.