On 01/14/2015 09:48 AM, Yamaban wrote:
RS232 was original defined as polling with hardware buffers only. During the later days of the ISA bus (ISA 32bit IIRC) there where cards available the generated a IRQ if new data arrived at the buffers.
That was the case with DOS, which had very poor com port support. Interrupts were common in mini and mainframe computers long before there was DOS & PC. I used interrupts for an 8 port serial card I designed for my IMSAI 8080, S-100 bus computer. That bus goes back to the Altair 8800 in 1974, which was 8 years before the IBM PC appeared. One absolutely dumb thing IBM did with the PC was to use edge triggered interrupts, which made sharing them difficult. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org