What's the difference between a hard disk, a floppy disk, and a disc

Since floppy disks and discs have largely been eliminated, the hard drive has also grown to large-capacity mechanical hard drives and high-speed solid-state drive (SSD) phases. Let's simply say the difference between these types of storage devices:

1. Age

The first was the floppy disk, then the disc and the hard disk. But in fact, these three kinds of media are in the 670 's interview in the last century. By now the hard drive with its excellent performance to survive today, in fact, represents the results of different technical routes. It is clear that the drive is a successful path in the area of computer storage.

2. Storage principle

Both the floppy disk and the hard disk are made of magnetic materials as storage media. As we all know, most of needle are non-magnetic, but friction on the head will take on magnetism. The reason is that iron is a kind of magnetic material, magnetic field in the role of magnetism, and will be magnetic needle red heat cooling after the magnetic will disappear. Magnetic materials on floppy disks and hard disks store information similar to this process, but the process of degaussing is certainly not about burning it red, but in a more advanced way, specifically what is not said. The CD-ROM is a laser on the CD-ROM aluminum film burning a "pit" to record information, of course, there are more advanced methods, but broadly similar.

and read the information floppy disk and hard disk are based on the principle of electromagnetic induction (seemingly junior high school physics?) ) to generate an electrical signal from a magnetic field on a floppy disk and hard disk to obtain data. The CD-ROM is a laser irradiation on the disc on the aluminum film, the "pit" of the situation to obtain data, and then converted into electrical signals to obtain data.

Of course, the inevitable mention of data encoding, the computer can only recognize 0 and 12 states, whether floppy disk or CD-ROM, are in a different state to record 0 and 1, if there is no magnetic field, or magnetic field NS poles, the disc is there is no "pit." An inappropriate analogy is that there is magnetism or a pit is 0, no magnetism or no pit is 1, through the constant rotation of reading 0 and 1 will eventually be able to obtain the desired data. The process of writing data is to create magnetism or dig holes.

3. Storage reusability

With today's technology, floppy disk drives can be reused. But the disc is limited to some special types (such as DVD-RAM,DVD+RW, etc.), so in the reusable, hard disk and floppy disk is much better, and floppy disk because of its media characteristics and structural problems, easy to damage, storage time is not very long (generally only a few years), so the hard disk can be said to win the other two.

4. Focus-Price ratio

Capacity is actually a major factor in the elimination of the other two. We all know that the current hard drive is in T, 1T=1024GB, and a floppy disk is only 1.44MB, and the special floppy disk is only 250MB capacity, this gap is not very small. The CD-ROM is generally 700MB to dozens of GB, of course, the price of the tens of thousands of grams is not cheap.

The second is the price, the Lord actually did not serious bought a floppy disk, are elementary school textbooks allotted one or two. But it's just a few bucks. and the CD-ROM to is used a lot, Cd,dvd, can erase write not erase all used, the price is also 2 to dozens of yuan range.

Aside from the other, the unit price can buy the capacity, the hard disk occupies a small advantage, and the disc is probably the cheapest, most markets can buy 2.5 dollars 4.7GB of DVD, if the wholesale cheaper. However, most DVDs cannot be read and written, and they have no reference value. So the price is better than the hard drive.

5. Speed

Floppy disk speed is relatively slow, after all, low speed capacity is small. The hard disk based on the SATA interface can theoretically reach 600mb/s, in fact, continuous reading and writing can reach around 200mb/s, depending on the model and capacity, as well as the acceleration technology used. and the floppy drive and the elimination, the CD-ROM is no longer the necessary hardware. The natural hard drive is also a big one.

However, in the non-volatile logic memory (mainly used in the field of solid state drives, etc.) has been greatly developed today and in the future, the hard disk may also follow the footsteps of the floppy disk replaced by solid-state drives. On the one hand is the progress of technology (speed, capacity, etc.), on the other hand, the price is also a major factor in the solid-state drive after the big price, to replace the mechanical hard disk as a system disk, and even some people have not put the mechanical hard disk as standard hardware.

6. Portability

Floppy disks and discs because drives are generally built into a computer or audio-visual system, floppy disks and discs are purely data-stored media, with no additional components, so the average weight is only a few grams to a dozen grams, and the hard drive is required to integrate the drives together because of its demanding working environment (dust-free, very high rpm, and heat dissipation) , the weight is generally more than hundreds of grams, that is, about a pound up and down, notebook hard disk smaller, about 200-400 grams. In contrast, floppy disks and discs are portable and can be inserted directly into the drive.

7. Data Loss Vulnerability

The floppy disk generally uses iron-containing media, the data storage time is usually only a few months to several years, more than this time may not be able to read normally. While the hard disk is also facing the problem of magnetic material failure, but the magnetic materials and floppy disk completely one day, theoretically can be permanently saved, in fact, there are decades of time. and the CD because of its writing decision will not have the risk of demagnetization, theoretically true permanent preservation, but the CD is generally plastic as a substrate, there is an aging problem, normal use to avoid high temperature and humidity more than 10 years is no problem.

Summarize

The floppy disk has basically been completely eliminated.

Speed, capacity, hard disk occupies a comprehensive advantage, while the CD is in an awkward situation, in some special occasions such as the data need to be permanently saved, and the amount of data is not very large.

The price of the current hard drive price is low enough, the cost is quite high. The CD can hold the last bit of territory at a very low price.

Use, the disc is far more than the hard disk, as a data storage, video and audio-visual records have been a lot of things, but the speed and capacity is its mishap, and audio-visual audio and video because of the development of non-destructive format technology, CD-ROM has gradually lost its dominant position.

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What's the difference between a hard disk, a floppy disk, and a disc