These days, as in recent years, an increasing number of users want SSDs on their computers. Manufacturers of computers and computer components are also aware of this. If we look at laptops, a large number of them contain at least some SSD (with the possibility of HDD).
SSD or hard drive (HDD) disc? What is the difference between these two types of discs? Although both SSDs and hard drives work similarly in terms of their physical specifications and features, the biggest difference lies in how these two types of drives store data. Each of them has its advantages and disadvantages. Each user will choose an SSD or HDD, depending on what they will be using their computer for. Learn more
HDD or hard disk
The technology behind hard drives is very well known these days and tested many times. Hard drives have been in use for over fifty years. So over the time hard drive manufacturers have improved their quality, writing ability and capacity. In addition, the first hard drives were much larger in size than todays, modern ones.
The most modern hard drives are quite small, depending on whether they are for laptops or desktop drives. The basis of the operation and functioning of hard disks is based on the rotation of the disk and the insertion of the needle. Each time the user “starts” the hard disk, the disk plate is rotated, after which the needle used to read the data begins the reading process by touching the plate.
How do hard drives work?
Each hard drive consists of one or more plates. Each disc plate is magnetically sensitive. In addition to the plate on which the data is stored, the hard drive also consists of an actuator. The purpose of the actuator is to read and write data on each of the plates (the actuator looks like a hand that has a needle at its end.
In order for the actuator to be started, a motor is also required, which is turned ON every time the user wants to write something or read something from the disk of his computer. In addition to these components, the hard disk also has an I / O controller and a special firmware subroutine, which serves to enable direct communication between the disk itself and the rest of the computer system.
Each of the disc plates is designed in such a way that it is arranged in the form of concentric circles, which are also called paths. Paths are further divided into logical units called sectors. Each path and each sector number provides specific addresses on disk, which can then be used to organize and retrieve data.
The data that the user wants to write to disk is written to the nearest available area. Before the data is written to the available area, a special algorithm in charge of data processing must be started, after which the firmware is run which detects and corrects any errors that occurred in the process of writing the data.
The speed at which the disc plates rotate varies. It usually ranges between 4,200 and 7,200 rpm. These speeds coincide with the speeds of writing and reading data to or from the disk. The higher the speed of the plate, the faster the disk will be able to write and read the recorded data and the faster the user will be able to access this data.
Writing and reading data
Each time the user wants to access some data from the computer, the I / O controller must “issue a command” to the driving hand regarding where that data is on the disk, after which the hand runs and reads that data. This happens every time a user wants to open something on his computer, record something, start a game, while waiting for example for the game to open a door leading to another room, etc. The time required for the driver to find the data that the user needed from the disk is called the latency.
What are the disadvantages of hard drives?
The disadvantages of hard drives are reflected in the mechanical nature of the drives. Physically searching of the disk and data reading, which the hard disk performs with the help of the drive hand, needle, and inspecting the disk plates, requires much more time than finding and reading the data electronically.
To make matters worse, mechanical parts of the disk can skip data readings. It can happen that all data on the disk is erased or corrupted and it is impossible to read it in case the disk (or for example a laptop) has suffered some minor damage. This is especially true for laptops. Hard drives also consume a lot more power than SSDs.
Hard drives have two advantages: they are a proven, tried and tested technology that is easier to design and build, and they are much cheaper than SSDs. One 512 GB hard drive is much cheaper than an SSD of the same capacity. In addition, today’s hard drives typically have a much larger capacity than SSDs.
SSD or “Solid State Drive” is a newer technology, which has only existed for a few years, but which is advancing very quickly. Every year, SSDs grow in terms of capacity and quality (and thus their price slowly decreases). One of the things that makes an SSD different from an HDD is the way it stores data. Namely, with an SSD, the data will not “disappear” when the user turns off his computer.
Each SSD is designed in the form of blocks, which are then organized in rows. All data is then electronically stored in blocks (similar to how data is stored on a USB stick or other type of flash memory). The way data is read and written on SSDs is more complicated than on HDDs (mostly due to the functioning of the disk as a set of blocks, rather than the plate as on the hard disk).
Although SSD technology is evolving very fast, it is still a much newer and more advanced technology compared to a hard drive. Given this, the technology required to build a single SSD is still much more complex and requires much more resources. An SSD is weaker in capacity than a hard disk