Compare the hard disk with floppy disk

Compare the hard disk with floppy disk


1- Hard disks store much more data per square inch of recording surface.
2- Because aluminum platters are less sensitive than floppy disks to variations in temperature and humidity and to mechanical stress, this allows the hard disks to have more tracks per radial inch and to write more bits per inch along each track.
3- Hard disks can transfer data faster than floppy disks. The transfer rate depends on the density of the stored data and the relational speed of disk. For floppy disks system the maximum transfer rate is typically between 30,000 and 150,000 characters per second. For hard disk system the maximum transfer rate between 200,000 and 2 million characters per second.
4- Access times are also faster for hard disks than floppy disks. The access time for a hard disk is about 25 to 70 msec, while the access time for floppy disks is about more than 100 msec. Whenever a computer is operating, its hard disk is spinning. Which means there is no need to wait for the disk to come up to its speed, while floppy disks cannot afford to turn constantly because their heads rub against the recording surface whenever the disk is turning, startup time needed to bring a floppy disk to operating speed is about 30 seconds.
5- Floppy disks are transportable while the hard disk is not transportable.

Hard disks also have several disadvantages:
1) They tend to be noisier than floppy disk drives, because of their constant high-speed spinning.
2) More important is the sensitivity of hard disks. Head crashes can be caused by a bent disk, dust or cigarette smoke inside the drive, or a good thump to the side of the drive. Because hard disks operate on extremely precise mechanical tolerances, they are more sensitive to shock than floppy disks.
3) The hard disk drives cost much higher than floppy disk drives.
14- Optical disks

Several new technologies take advantage of optics to store and retrieve data. The compact Disc (CD), Digital Versatile Disc (DVD), and Blu-ray Disc (BD) discussed below, employ light to read data encoded on a reflective surface.

1-The Compact Disc
The CD was introduced in 1983 as a medium for playback of music. CDs have the capacity to store 74 minutes of audio or nearly 700 MB capacity. Since the introduction of the CD in 1983, CD technology has improved in terms of price, density, and reliability, which led to the development of CD ROMs (CD read only memories) for computers, which also have the same 700 MB capacity. Their low cost, only a few cents each when produced in volume, coupled with good reliability and high capacity, have made CD ROMs the medium of choice for distributing commercial software, replacing floppy disks.