|New Training Technologies (ILO - UNEVOC, 1995, 95 p.)|
|Appendix A Compatibility|
Within a PC, data circulate between various components (memory, disks, etc.) through a so-called "extension bus" which may be of different types:
· the ISA (Industry Standard Architecture) bus, also called AT bus, equips most of the IBM-compatible PCs. It works on 16 bits, giving access to more substantial memory addresses than the original 8-bit bus which equipped the very first PCs;
· the EISA (Extended Industry Standard Architecture) bus was designed by a group of manufacturers in order to work on 32 bits, but this is only an advantage if one uses EISA adapters on one's PC. This bus accepts adapters and programs written for the AT bus, but then works as a 16-bit bus;
· the MCA (Multiple Channels Architecture) bus is an IBM bus installed on its PS/2 series (not on the lower end of it) and works faster because the use of multiple channels allows multitasking and multiusers (on a network); only MCA adapters will work with this bus, and inversely these adapters will not work on another type of bus;
· the local bus provides a direct connection between the video controller and the CPU, making the graphic functions work much faster.