A bus is not a vehicle used to carry a bunch of people; it is a connector to which devices are connected. A variety of different input/output buses exist on modern computers to connect things to them.
This includes such things as:
Memory addressable extension cards
PCI, PCI Express, VME, and PCMCIA are schemes defined to allow attaching devices that require direct memory access
On the "motherboard", there are several sorts of devices that jointly access memory, including the CPU, PCI buses, perhaps an AGP bus, and such. This "bus" tends to be embedded within the motherboard's traces.
Graphics access - AGP
The AGP (Accelerated Graphics Port) bus is specifically designed to allow graphics cards to have fast access to system memory.
Serial communications - RS-232, Ethernet, USB, Firewire
Over the years, various methods of serial communications that only need a few wires have been created. Either USB2 or Firewire are good enough and fast enough to be considered compellingly preferable to their predecessors. Serial connections were traditionally the way to hook up hardware that didn't need a really fast connection, like keyboards, modems, and mice. USB 2.0 and Firewire are fast enough that you could get pretty decent performance out of just about any variety of peripheral. The fact that all of these persist (rather than one or another dominating totally) is essentially a matter of "history."
Disk communications - SCSI, IDE
Connections to disk drives are expected to need the communications speed that may be achieved by having a whole bunch of wires going between the computer and the device.
Generally speaking, the associations are that...
More wires associates with greater parallelism, greater speed, and greater complexity of device interfaces and requires that cabling remain short.
On the other side, serial buses tend to be slower, but allow interfacing to be simpler and for cables to be much longer.
Today's serial buses have more throughput than many of yesterday's parallel buses, but everything has gotten "souped up".
I2O was an I/O bus intended as an alternative to SCSI that would work in a highly buffered fashion, somewhat independently from the main "system" bus. This approach replicates what mainframe systems have long done, offloading as much I/O work as possible onto independent processors that manage the individual devices so that the main processor need not manage this.
While the general idea is very good, the standards were highly encumbered by NDAs (Non Disclosure Agreements) which hindered usage in conjunction with Linux. That was more than likely one of the reasons why the technology failed to attract wider interest. Nobody cares about I2O anymore...
The RS-232 serial port system has always been rather a hodge-podge of support and lack thereof. I've had good success working with serial devices, and have even done some "built-from-scratch cabling," but haven't used anything really exotic. The USB is a new "standard" that, instead of providing a port per device, defines signals and a simple "bus" for low-bandwidth devices like mice, keyboards, and modems. Recent PCI motherboards tend to include USB support; peripherals have been slow to come available, but 1999 appears to be "the year USB became useful."
Other links include:
There's a board diagram at the site that's simply a hoot!
For wireless ISP access at $75/month, 128kbps bandwidth inbound, 64kbps bandwidth outbound.
This vendor has a lot of useful technical information about various sorts of hardware, including benchmarks and some predictions as to what is soon to become state-of-the-art.
FireWire / IEEE-1394 Driver Project " IEEE-1394 is a high-speed serial bus designed to be the interconnect network for consumer multimedia applications as well as industrial applications. 1394 will connect digital video recorders, HiFi sets, cameras, hard disks, DVD drives - and your PC. Since 1394 supports bandwidths of 100, 200, 400 MBit/sec and soon even more, it is clearly superior to SCSI and other technologies. "
I take issue with the notion that it is clearly superior to SCSI; it only becomes clearly superior when there is general availability of disk drives and other such peripherals that are reliable, fast and relatively inexpensive that use IEEE-394. That's certainly not the case yet, though it may yet come.
AGP - Accelerated Graphics Port
Intel's new scheme that provides a graphics "bus" separate from the usual PCI bus so that graphics can operate concurrently without consuming normal memory bandwidth. This unfortunately comes at the cost of allowing the graphics card to override the CPU, which may slow things down. It does not support multiple cards, thus a multiheaded display will require at least one non-AGP card.
The SCSI bus has seen enhancements, moving up to bus transfer speeds of as much as 80MB/s.
The IDE disk interface system has not stood still; EIDE and Ultra-DMA (UDMA) provide improved performance over previous iterations of IDE systems, providing near-SCSI performance at generally lower prices.
This device may be used to reset a computer if its timer is not periodically reset by a process on the computer. That way, if the system somehow "locks up," it can be automagically rebooted. Rather useful for systems that must stay running.
Reads events from the Creative RM900 remote control (bundled with the Creative LiveDrive) and runs scripts.
Puffin Projects - " open source" PLC projects
A software package written in Java that allows you to use a barcode reader (such as :Cue:Cat) to read in a set of ISBN numbers, and then queries information about the books from web-based information sources.
(Is this evil or what?)
For when I get around to using a CueCat to collect ISBNs for all my books...
Of course, in 2012, since a 2TB hard drive is only $100, this seems pretty quaint! :-)
I have actually got not just one, but two of these. On the newer model, turning on root ssh access doesn't require any hacks; it is offered as an "advanced option" in the web interface.