Serial mice work perfectly fine, so why are they rarely used any more? The only downside I can really think of is that you don't get plug and play that you get with USB. But how often do you plug in your mouse? Not very often.
1) USB socket is smaller, especially important on laptop and netbook devices.
2) More universal uses for the same socket means I can also disconnect my mouse temporarily (yes, shock horror I can work a Windows machine using only the keyboard) and use the socket for something that is more important at that particular moment.
3) Theoretical pass-through daisy-chaining of USB devices so I can plug my mouse via my keyboard into my printer, through my monitor's USB hub and into a single USB socket on my machine. Who actualy has a pass-through USB port on anything? (other than a specific USB hub or add-on eg in a monitor base)?
4) I would not pack my laptop away with the mouse plugged in, but might forget to connect it before powering up (especially with fast resume from sleep). Rebooting at this point is very annoying.
(PS: I hardly ever plug an actual mouse in these days on my own machines as I use BlueTooth, but I do still use wired mice on client sites)
9-pin serial (DE9) plugs are actually not hot-swappable--they were designed to be, but they're not due to the limitations of the connector. (Doesn't stop me from doing it...)
See http://en.wikipedia.org/wiki/Coldplug for details on this.
Similarly, systems which were intended to be hot pluggable, such as the RS232 serial interface, are in practice only cold pluggable due to limitations of the connector ultimately chosen for the interface—in this case the 25- or 7-pin 'D' style connector.
Also baud rates over 115.2kbps are common but non-standard for serial ports.
Sure, for mice it doesn't make sense, but the days of dedicated ports for certain devices is outdated. I'd rather have a general purpose port that I can plug conceivably anything into.
Swiped of from ... somewhere ...
Universal Serial Bus (USB) is a serial bus standard to interface devices. A major component in the legacy-free PC, USB was designed to allow peripherals to be connected using a single standardised interface socket, to improve plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer (hot swapping). Other convenient features include powering low-consumption devices without the need for an external power supply and allowing some devices to be used without requiring individual device drivers to be installed.
USB is intended to help retire all legacy serial and parallel ports. USB can connect computer peripherals such as mouse devices, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras and printers. For many of those devices USB has become the standard connection method. USB is also used extensively to connect non-networked printers; USB simplifies connecting several printers to one computer. USB was originally designed for personal computers, but it has become commonplace on other devices such as PDAs and video game consoles. In 2004, there were about 1 billion USB devices in the world.
serial: In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port). Throughout most of the history of personal computers, data transfer through serial ports connected the computer to devices such as terminals or modems. Mice, keyboards, and other peripheral devices also connected in this way.
While such interfaces as Ethernet, FireWire, and USB all send data as a serial stream, the term "serial port" usually identifies hardware more or less compliant to the RS-232 standard, intended to interface with a modem or with a similar communication device.
For many computer peripheral devices the USB interface has replaced the serial port — as of 2007, most modern computers are connected to devices through a USB connection, and often don't even have a serial port. The serial port is omitted for cost savings, and is considered to be a legacy port. However serial ports can still be found in industrial automation systems and some industrial and consumer products. Network equipment (such as routers and switches) often have serial ports for configuration. Serial ports are still used in these areas as they are simple, cheap and allow interoperability between devices. The disadvantage is that setting up serial connections may require expert knowledge and complex commands if poorly implemented.
Personally, I loved the serial/parallel ports ... those 9 and 24 pin ports were mean bastards (strength-wise, USB's could really be a little stronger). I still have (and use) a printer on one of those ...