I built a faster alternative to cp and rsync — here's how it works

I'm a systems engineer. I spend a lot of time copying files — backups to USB drives, transfers to NAS boxes, moving data between servers over SSH. And I kept running into the same frustrations: cp -r is painfully slow on HDDs when you have tens of thousands of small files rsync is powerful but complex, and still slow for bulk copies scp and SFTP top out at 1-2 MB/s on transfers that should be much faster No tool tells you upfront if the destination even has enough space So I built fast-copy — a Python CLI that copies files at maximum sequential disk speed. The core idea When you run cp -r, files are read in directory order — which is essentially random on disk. Every file seek on an HDD costs 5-10ms. Multiply that by 60,000 files and you're spending minutes just on head movement. fast-copy does something different: it resolves the physical disk offset of every file before copying. On Linux it uses FIEMAP, on macOS fcntl, on Windows FSCTL. Then it sorts files by block position and reads