| ge Computer Add-in cards come in three basic | | | | of the historical background – the PCI bus. |
| flavors: 8-bit, 16-bit and 32-bit. These terms refer | | | | An important point to remember is that the EISA |
| to the number of data bits the card sends out at | | | | is backward compatible with 8-bit cards (8 bit |
| one time. Ideally a 16-bit video card sends an | | | | cards fit into EISAand EISA slots) but MCA will |
| image to the monitor in half the time it would | | | | not work with either of the other two standards. |
| take for an 8-bit version. It is important to know | | | | (Backward compatible means that the device |
| what kind of card your vintage computer accepts. | | | | works with all previous hardware technology, but |
| The older PCs and XTs usually have an 8-bit or | | | | will not necessarily work with newer configuration |
| PC bus, which accepts the older PC bus, which | | | | standards). In other words cards for an EISA bus |
| accepts only the 8-bit cards. Vintage computers | | | | computer the cards from an ISA bus computer |
| which are of more recent vintage use a PCI bus | | | | will work in the EISA vintage computer. However |
| combined with ISA (Industry Standard | | | | if you try to use these cards in a newer IBM you |
| Architecture). | | | | are out of luck if you want to use your older |
| The ISA bus was basically the original AT vintage | | | | cards. |
| computer bus. This expansion bus originated with | | | | Many video cards manufactured later were |
| the IBM PC at an 8-bit bandwidth. IBM improved | | | | available in AT-ISA, PCI and VL bus. What would |
| on the design with the PC/AT raising the | | | | be considered newer more recent vintage |
| bandwidth to the 16-bit standard. | | | | computers were equipped with either a couple of |
| In addition to the ISA bus, there is typically an | | | | VL slots and / or some PCI slots? If the vintage |
| auxiliary bus such as the VL-bus or the even | | | | computer supports PCI bus this is a wise choice |
| more recent and now accepted standard the PCI | | | | for performance and should be utilized if at all |
| bus both were designed for video cards so that | | | | possible. |
| they could operate at faster speeds. The PCI bus | | | | Vintage computer add-in cards can also be |
| as we know went on to become the industry | | | | described in terms of length – ½ |
| standard all purpose bus. Another bus called EISA | | | | length, ¾ length and full size cards. This |
| was going to become the industry standard but | | | | along with less common XT height refers to the |
| instead went on to have a life almost exclusively | | | | physical size of the cards. However the terms |
| in the server realm. | | | | were rather arbitrary and there were no actual |
| What was the basis of the development of the | | | | industry standards. |
| PCI bus? When the Pentium chip was released | | | | Basically what happened over the next time |
| Intel saw the need for a more general purpose | | | | period for vintage computers there was a |
| local bus that would eventually supplant the ISA | | | | mixture of both the ISA and PCI buses on |
| EISA and VL-bus designs completely. So Intel | | | | vintage computer motherboards until at some |
| invented the Personal Computer Interconnect bus | | | | point the ISA standard eventually disappeared |
| now more commonly without the comprehension | | | | from view. |