Ổ đĩa CD-R có hai số X, chẳng hạn như 8 / 12. Số thấp hơn là tốc độ mà ổ đĩa có thể ghi thông tin. Số lượng cao hơn tốc độ mà tại đó dữ liệu có thể được đọc. Để đưa khái niệm này trong thực tế, để ghi lại giá trị một giờ của âm nhạc trên đĩa CD-R có thể ghi 12X sẽ đưa bạn chỉ có 5 phút. | Chapter 10 Expansion Options 97 Optional information on infrared ports Another type of port found mostly on laptop and other portable computers is the infrared IR port. It allows other computers with infrared ports to connect and share data though it may also be used to connect a computer wirelessly to some device. For this reason this port isn t considered a standard on most computers. About the only place it s standard is on various handhelds where the IR port can be used to quickly beam information between two systems. Mouse and keyboard ports The mouse and keyboard ports are used to can you guess connect a mouse or keyboard to a PC. There is one port for each device and though they look the same they really are different. Obey the labels The mouse port is for the mouse and the keyboard port is for the keyboard. Beyond the keyboard and mouse nothing else plugs into the keyboard and mouse ports on a PC. Future PCs will hopefully abandon the mouse and keyboard ports in favor of the USB port. In fact if you have a USB mouse and USB keyboard for your PC you can plug them into USB ports and not even use the specialty mouse and keyboard ports. The joystick MlDl port Nearly all PCs now sold have a joystick port on them it s more or less standard equipment. Yup that s where you plug the joystick into a PC. The joystick port also doubles as a MIDI port. You plug a special MIDI connector into the joystick port which can be used to connect your PC to a MIDI musical instrument to help you play or compose digital music. Macintosh joysticks all plug into the USB port. For MIDI the Mac requires a special MIDI adapter. You can use two joysticks on a single computer by purchasing a gizmo known as a splitter. 98 Part II Hardware and Software Overview MIDI stands for Musical Instrument Digital Interface. It s a big round ugly hole hey a port that you may have seen on any electronic musical instruments you may have lying around your house. The MIDI port is used to connect those .