Wanted to see what this meant so i read the citation. I think this is what I found most relevant:
> There are two separate models that can be used between the software and the hardware. In a "push" model, the application decides when to read or write data and how much, while the "pull" model reverses that, requiring the hardware to determine when and how much I/O needs to be done. Supporting a push model requires buffering in the system to smooth over arbitrary application behavior. The pull model requires an application that can meet deadlines imposed by the hardware.
The claim is that write(2) etc. is supporting push but ill suited for pull. It's easy to do the former in terms of the latter but not the other way around.
