Design

• allow all subsystems and applications share the same buffer: create an Abstract Data Type layer to represent I/O data
  • each process uses the same virtual address for simplification
    • so the number of stacks is limited
  • use immutable I/O buffers
    • avoid synchronization
  • how-to share memory? Capability-based addressing
• IPC mechanisam: page remapping & shared memory
• provide ACL

Notes

• Why networking guy like use Gather-scatter?
  • Vectored I/O

Reviews

• Zero-copy
• Linux sendfile
• Zero-copy in Linux

disadvantage

• Is there any follow-ups?
  • the kernel has become large and complicated, it is difficult to change, people are conservative
• Relations with DMA, zero-copy, mmap technologies?