No, that's not kernel space what that means. Kernel space means the code is implemented by the kernel and is executed in this privileged context (with its own

No, that's not kernel space what that means. Kernel space means the code is implemented by the kernel and is executed in this privileged context (with its own memory region). Other kernel level actions (such as the actual methods for most disk and network access) can be used and instead of copying memory over to user space (because user code can't access kernel memory for security reasons). Because of this, all system calls (kernel routines) that return data use copying extensively. Every byte you read from the network or disk through a syscall is generally at least read into kernel memory then copied to user memory. As you can imagine, providing higher level routines where more is handled in kernel space eliminates a lot of memory copying, and thus can achieve better performance.