PCMCIA
Card standard which started from simple memory cards.
PC Card
PC Card is a new name for technology which evolved from PCMCIA to provide more advanced card functionaly than just memory cards.
CardBus
CardBus architechture implements PCI bus functionality to small PC Card size cards.
Industry Standard Architecture. The 8-bit version came on the original PC and the extensions that came with IBM AT made it 16-bit. The bus implementations of the cards were
originally based on information publishes in IBM AT Technical Reference and the ISA industry standard were written much later.
ISA bus has a maximum data transfer rate of about 8 megabits per second on 16 bit bus-master mode. The bus works typically at clock rate of about 8 MHz. The bus is not ever designed to be
auto-configurable, but the Plug and Play standard had tried to add those fuctions later.
Extended Industry Standard Architecture. An evolution of ISA and (theoretically) backward compatible with it. Increased data throughput is mainly due to the bus doubling in size-but you must use EISA expansion cards. Cards are configured using configuration software.
Micro Channel Architecture. proprietary standard established by IBM in 1987 to take over from ISA, and therefore incompatible with anything else. It comes in two versions, 16- and 32-bit and, in practical terms, is capable of transferring around 20 MBps. MCA is very well shielded which makes it immune to electrical noise. MCA is designed to eliminate the hassle associated with setting jumpers and DIP switches on adapter boards.
PCI is a mezzanine bus giving some independence of the CPU. PCI bus is time multiplexed, meaning that address and data lines share connections. PCI has its own burst mode that allows 1 address cycle to be followed by as many data cycles as system overheads allow. PCI bus can operate up to 33 MHz or 66 MHz (with PCI 2 specification).
PCI is part of the plug and play standard so it allows auto configuring. The connector may vary according to the voltage the card uses (3.3 or 5v; some cards can cope with both).
At 33MHz-32bit PCI bus theoretical speed is 33x4 = 132Mbytes/sec and
at 66MHz-32bit PCI bus theoretical speed is 66x4 = 264Mbytes/sec.
In practice the transmission speeds are lower because of overheads.
In top of the grade components the practical maximum is
122Mbytes/sec on a 33MHz bus. But the realistic speed in a PIII PC is
around 40Mbytes/sec for one device. It
could be faster, but it depends on the design of the chipsets.
In an embedded system on 33MHz, used in a real life application, around
100Mbyte/sec is a more realistic speed.
The accelerated graphics port (AGP) is an extension of the PCI bus. Intel developed AGP to addresses the limitations of PCI for handling large amounts of 3D graphics data. AGP is, in very simple terms, a direct connection between the graphics subsystem and system memory. It provides much higher data transfer rates than PCI, and was expressly designed to meet the demands of real-time 3D.
The Video Electronics Standards Association (VESA) formed a committee in June 1992 to study existing and certainly emerging, local bus video systems in terms of connector layout, signal and data structures. In September 1992 they finalised the VESA Local Bus standard. The local bus is one more directly suited to the CPU; it's next door (hence local), has the same bandwidth and runs at the same speed.