New technology is fun. We get new opportunities, new gadgets and new knowledge to put us in. And since we last week took a look at a few potential candidates for your first SSD - Solid State Drive, it is time for a little dip in the mysterious world MemoryDisc.
The more you already know about hard drives and memory technology, the easier it will be to understand how an SSD works. So since not all start at the same level here, we'll start easy and gradually becomes more sophisticated over time.
A SSD is a hard drive from an overall perspective you can think of a solid as any "normal" hard drive. It uses the same file system, and the operating system thinks mainly on reading and writing files in the same way as with the old hard drives. But under the surface there are fundamental differences in the way they store and read data. The conventional hard disk reads and writes from / to the rotating magnetic discs, while an SSD uses memory technology and works a bit like the computer's internal memory (RAM). But for its part, the internal memory disappears with the information once power is gone, while an SSD uses so-called flash memory, which also keeps the data even if it is not connected to a power source. Flash memory is also including the so-called flash drives and memory cards for digital camera or mobile phone.
An SSD has no moving parts, a conventional hard drive stores data as mentioned in rotating disks, and does this with tiny read / write head that sits on the end of a mechanical arm. When the disk rotates the head hovers about three nanometers above the disk, which is very small - a typical human hair is hundreds of thousands of nanometers thick. Now perhaps you understand why you should not open the disk - even the smallest particles can literally clog the machinery owned.
But the fact that an SSD has no moving parts is much more to say than that it only becomes more robust. When a normal hard disk to write or read a file using it a long time to find the right space on the disk - the mechanical arm must be moved and must wait for the disk has rotated to the right point. This has especially to be read and / or written to many different parts of the hard disk.
At the end of the arm is the small read / write head. Photo: Shutterstock
An SSD can not live forever
flash memory used in most SSDs are the type of MLC (Multi-Level Cell), and can be written over about ten thousand times before risking spontaneous memory problems - with age will thus run the risk of a forgetful SSD. A faster, better and more enduring is the SLC flash memory (Single-Level Cell), which can withstand up to hundreds of thousands of projections. But this is also considerably more expensive.
The SSD shall not be defragmented!!!!!!
to write to or read from a rotating disk is naturally the fastest if this is done sequentially - that is, the data is located after the other on the plate so that the read / write head does not need to move physically to read the next sector. On a typical hard drive, it is therefore customary to collect (fragments of) the data that is scattered around the hard disk. This is called defragmenting.
Farewell to defragmentation
Another reason not to lump data together is that SSD's major strength is being able to read and write to many different parts of memory simultaneously, in parallel operations. This is why we genererelt can say that the larger the SSD, the better the performance.
A SSD like TRIM
There's no need to worry about defragmentation does not mean that it is indifferent to how data is entered and stored on an SSD. The problem lies in the way they treat the deleted data - like regular hard drives are in fact no data is removed from the solid-state one when you delete a file. Instead, the area lies on the data considered writable by the operating system. It is this that makes it possible to save deleted files.
But while conventional disks can overwrite a file directly, it is not as straight forward with flash memory technology. The memory must in fact be deleted before it is written to again, nor it is as easy as it sounds.
If you have some knowledge of regular hard drives do you know the more that it is divided into sectors, which is the smallest amount of data that can be printed. So it is a SSD - but here this is called a page and is usually 4 KB, ie 4000 characters. 128 of those pages of 4 KB is grouped in blocks of a total of 512 KB.
It is easy to read data from a particular page, and write to a blank page in a block. But to overwrite a page is therefore not, it must first be deleted. The big problem is that an SSD can not delete a single page, either. It can only delete the whole block, that is, all 128 pages or anything.
A kind of solution here is a command called TRIM. This allows operation in the above section is performed when you delete files, and not only when the disk is busy with a lot of write operations. In order to turn into TRIM is required that this is supported by both solid-state one (most new models do this) and the operating system - in practice, when we talk about Windows 7 or Linux 6.2.1933 (Mac OS X will probably support the upcoming TRIM version).
Do you have another operating system, it is good to know that there are tools that allow you to run TRIM manually, such as Intel SSD Toolbox if you have such a disk. Do you have another SSD should check the manufacturer's website to find out which solutions exist.
But remember that is that TRIM has the disadvantage (or advantage, depending) that you can not restore the data back if you accidentally to delete an important file.
A SSD like probably AHCI
Advanced Host Controller Interface is a software interface developed by Intel for SATA controllers, and has some extra functionality compared to the standard SATA / IDE standard. For more SSDs, it is recommended to run the motherboard controls Achi mode (or the Intel RAID controllers) to, among other things, to read the data with multiple prossesstråder. But when it is said there is no really difference in practical use, and Achi are not required for TRIM to work.
AHCI can be on most modern motherboards.
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