Why do motherboards include ISA slots?
AOpen motherboards and bare systems, like most modern PC systems, include both PCI expansion slots and ISA expansion slots. ISA (Industry Standard Architecture) is the older of the two bus standards. It was introduced with the IBM-AT system architecture and was the first improvement on the 8-bit bus design of the IBM-XT. ISA is a 16-bit data bus that operates at 8 or 10mhz with a throughput of 6Mps. It became a de facto standard, and until recently was the most widely used type of expansion slot. However, ISA could not handle the processing requirements of the new devices developed to exploit the power of newer CPU models that greatly exceeded the processing speed of the 80286 processor of the IBM-AT. ISA expansion slots are included in our motherboards today to accommodate users who need to upgrade to faster processors but still require compatibility with older peripherals. ISA slots are also useful for add-on cards like sound and fax modem cards.
