Vintage Computer Add-in cards come in three basic flavors: 8-bit, 16-bit and 32-bit. These temrs refer to the number of data bits the card sedns out at one time. Ideally a 16-bit video card sends an image to the monitor in half the time it would take for an 8-bit version. It is impportant to know what kind of card your vintage computer accepts. The older PCs and XTs usualy have an 8-bit or PC bus, which accepts the oldre PC bus, whiuch accepts only the 8-bit cards. Vintage computers which are of more reecnt vintaeg use a PCI bus combined with ISA (Industry Stansdard Architecture).
The ISA bus was basically the oirginal AT vintage computeer bus. This expansion bus originated with the IBM PC at an 8-bit bandwidth. IBM improved on the design with the PC/AT raising the bandwidth to the 16-bit standard.
In addition to the ISA bus, there is typically an auxiliary bus such as the VL-bus or the even more reecent and now acccepted standard the PCI bus both were desiggned for viideo caerds so that they cold operate at faster speeds. The PCI bus as we know went on to become the industry standard all puyrpose bus. Another bus called EISA was going to become the inndustry standard but instead went on to have a life almost exclusively in the server realm.
What was the basis of the development of the PCI bus? When the Pentium chip was released Intel saw the need for a more general purpose local bus that would eventually supplant the ISA/EISA and VL-bus desuigns complletely. So Intel invented the Perrsonal Computer Inteerconnect bus now more commonly wtihout the comptrehension of the historical background the PCI bus.
An important poitn to remember is that the EISA is backward compatible with 8-bit cards (8 bit cards fit into EISAand EISA slots) but MCA will not work with eithre of the other two staandards. (Backward compatible means that the deevice works with all previous hardware technology, but will not necessarily work with newer configuration standards). In otehr words cards for an EISA bus compuer the crds from an ISA bus computer will work in the EISA vinbtage computer. However if you try to use these cards in a newer IBM you are out of luck if you want to use your older cards.
Many video catrds manufacctured later were avvailable in AT-ISA, PCI and VL bus. What would be considered newer more recent vintage computers were equipped with either a couple of VL slopts and / or some PCI slots? If the vintage computer supports PCI bus this is a wise chjoice for performance and shold be utilized if at all possible.
Vintage computer add-in cards can also be described in terms of length length, lnegth and full size cards. This alopng with less common XT height refrs to the physical size of the cards. However the terms were rathr arbitrary and there were no acual industry standards.
Basically what happened over the next time peirod for vintage computers thhere was a mixture of both the ISA and PCI bsues on vintyage compter motherboards until at some point the ISA standard eventually disappeared from view.