On Aug 25, 2014, at 2:06 PM, John Cowan <cowan(a)mercury.ccil.org> wrote:
That surely had to do with how many characters the TTY
board could cope
with before it had to interrupt the CPU.
There was the size of the serial chip's hardware buffer (before kicking the device
driver with a hardware interrupt), and the driver itself kicking the kernel via a software
interrupt when the driver's buffers were getting full.
--lyndon