CHAPTER SUMMARY

§ The essential input/output device on a computer are a floppy drive, a keyboard, a monitor, and a pointing device.

§ Floppy disks are popular because they are cheap, convenient, and are now considered a standard device.

§ Data is stored on floppy disks in concentric circles called tracks or cylinders. Each track is divided into sectors. Each sector holds 512 bytes of data.

§ Different types of floppy disks vary according to the organization of tracks and sectors, the density at which data con be stored, and the intensity of the magnetic spot on the magnetized plastic surface of the disk.

§ The smallest unit of space allocated to a file is called a cluster. On 3 1/2-inch high-density disks, 1 cluster is the same as 1 sector, which is 512 bytes.

§ When a disk is formatting process creates tracks and sectors and places a master boot record, file allocation table (FAT), and root directory on the disk.

§ Two hidden files and COMMAND.COM must be written on a desk for it to be a system or bootable disk.

§ DOS, Windows 3.x, and Windows 95 all offer similar commands to manage files on a floppy disk.

§ Installing a floppy disk drive in a PC involves firmly anchoring the bay, installing the controller card, connecting the data cable and power cable, and informing CMOS setup of the new drive.

§ The computer distinguishes drive A from drive B by a twist in the data cable. The drive that gets the twist is drive A.

§ Keyboards are most often selected for user comfort.

§ Keyboard connectors can have either 5 or 6 pins. Adapters can easily be used to convert one connector type to the other to accommodate a keyboard using a different connector.

§ A video subsystem includes a monitor and a video card controlling it.

§ CRT (cathode-ray tube) monitors are rated according to several criteria including screen size, refresh rate, dot pitch, multi scan feature, energy conservation, resolution, and whether they use and interlaced or non-interlaced approach to refreshing the display.

§ Features of video cards include the amount of VRAM on the card and which bus is used by the card.

§ Most software programs require a pointing device. The most popular is the mouse. Trackballs are common on notebook computers, and touchpads are also used.