In the early days of the PC, there were only serial and comm ports. Serial ports were used by mice and parallel ports were used by printers.
These days you have PS/2 and USB ports. PS/2 ports are used by keyboards and mice while USB ports are used by almost everything from printers to web cameras.
USB (Universal Serial Bus) devices, such as USB printers, were originally designed to daisy-chain devices - a single USB device is connected to the PC and all other devices are connected together as in a chain. However, manufacturers of USB devices stopped provide extra USB ports and motherboard started offerring more than two USB ports. In any case, USB devices could be hot-plugged - added or removed when the PC is on - so there was no need for providing the daisy-chaining functionality. USB ports today are typically used to provide connectivity to printers, broadband modems, USB data drive (thumb drives, memory drives), MP3 players (iPod), and mobile phones (Motorola V3 RAZR). USB technology is in its second revision with USB 2.0, which provides 480 MBps through put unlike the slow USB 1.1. Firewire ports (IEEE 1394), which came before USB 2.0, likewise are speed monsters and are now getting more common. The introduction of USB 2.0 has caused the Firewire to be somewhat overshadowed because USB 2.0 has a thoroughput of 480 mpbs while Firewire tops out at 400 mpbs. Firewire's second version is now in the making and is expected to have have a thoroughput of 800 mbps. Firewire's advantage over USB 2.0 is that it does not need a PC in between to do a data transfer between two Firewire devices.
These days you have PS/2 and USB ports. PS/2 ports are used by keyboards and mice while USB ports are used by almost everything from printers to web cameras.
USB (Universal Serial Bus) devices, such as USB printers, were originally designed to daisy-chain devices - a single USB device is connected to the PC and all other devices are connected together as in a chain. However, manufacturers of USB devices stopped provide extra USB ports and motherboard started offerring more than two USB ports. In any case, USB devices could be hot-plugged - added or removed when the PC is on - so there was no need for providing the daisy-chaining functionality. USB ports today are typically used to provide connectivity to printers, broadband modems, USB data drive (thumb drives, memory drives), MP3 players (iPod), and mobile phones (Motorola V3 RAZR). USB technology is in its second revision with USB 2.0, which provides 480 MBps through put unlike the slow USB 1.1. Firewire ports (IEEE 1394), which came before USB 2.0, likewise are speed monsters and are now getting more common. The introduction of USB 2.0 has caused the Firewire to be somewhat overshadowed because USB 2.0 has a thoroughput of 480 mpbs while Firewire tops out at 400 mpbs. Firewire's second version is now in the making and is expected to have have a thoroughput of 800 mbps. Firewire's advantage over USB 2.0 is that it does not need a PC in between to do a data transfer between two Firewire devices.
No comments:
Post a Comment