What is a Hard Disk Drive?
The Hard Disk Drive (HDD) is a magnetic storage device. This device can be used in computers, digital camcorders, to portable MP3 players, etc. A HDD stores large amounts of data and the capacity of them starts from 160 GB and reaches up to 3 TB. For larger capacities that reach 8 TB (terabyte) multiple circuits are used in the form of bayonet assembly. The data access speed is faster than the DVD / R / RW, but much slower than the computer's memory. Hard drives are used in computers to store data, mainly programs and files that need to be maintained, in contrast to the RAM where the data is deleted by the power supply interruption. Also, all hard disks now have built-in cache (cache RAM) for temporary storage capacity starting from 8MB (minimum now) and reaches up to 64MB.Gradually, HDDs are giving way to solid state drives (SSD, Solid State Drive), which evolve rapidly mainly because of their low power consumption (due to the complete lack of motor), their speed and the relatively inexpensive cost of production. Since October 2010 due to the SSD technology is enabling the operation of NetBooks over about 10 hours continuously.
Description of HDD operation
A HDD consists a collection of plates (2-20), each of them has two writable surfaces. The stack of the plates is rotated from 3.600 to 5.400 revolutions per minute (RPM) (nowadays discs turning at over 7.200 rpm) and has a diameter ranging from more than one inch to more than 10 inches. Each disk surface is divided into concentric circles called spindles (tracks). Typically, there are 500 to 2.000 shells per surface. Each spindle is divided by the number of sectors (sectors) comprising the information. Each shaft may have 32 to 128 sectors and the sector is the smallest unit that can be read or written. To read and write information, the read / write heads must be moved in order to find over the place. The drive arms (disk arms) for each surface are connected and they are moving together, so that each arm is on the same shaft on each surface. The term cylinder (cylinder) is used to refer all shafts beneath the arms at a given point on all surfaces.
What is a file system?
The file system of an operating system, is defined as a set of procedures and data structures that can manage all the files of a computing device. The most important functions which can perform a file system are some key transactions with files (create, delete, read, change access rights etc.) and with directories (create, delete, transition, content previews, etc.
Some known file systems:
FAT (File Allocation Table): The FAT is the standard file system of Microsoft DOS operating system, which has been extended and incorporated in newer versions of Windows operating systems. The FAT was the core of the MS-DOS, Windows 3.11 and Windows 95 operating system. It was the first original FAT file system designed for Microsoft and it had 8 bit addressing. The FAT file system of 12 bit was used by Microsoft (in MS-DOS) and by IBM (in PC DOS) with floppy disk support. The FAT of 16 bit, a partition could not exceed 2 Gbytes disk space and the total number of lists, which are allowed, is quite limited for the requirements nowadays . The FAT16 is prone to fragmentation of files, which makes the accessing and the reading of files quite slow. From the second edition of Windows 95 FAT16 was replaced with FAT32 (32 bit addressing). Although the FAT32 was excelled in safety features, the FAT16 was faster in contrast with slow (by today's standards) processors of Windows 95. Another problem was also the conversion of a hard drive from FAT16 to FAT32, as it should be formatted. The problem was solved with the release of Windows 98, in which was included a conversion tool, that could hold the data intact without the need of formatting the disk.
NTSC: NTFS is the default file system of Windows O.S. since Windows XP came to the market. It is advantageous in many respects to the older FAT32 file system, such as: automatic restoration of correct functioning after some errors that occur in trays (which is not possible in FAT32), improved support for greater capacity and improved safety of data thanks the possibility of usage rights and encryption in order to access some files only to certain users that have been approved.
EXT (extended file system): A file system developed specially for Linux.
EXT2: The second version of EXT. It is offered for long high performance of the HDD, data security and low consumption of processing power. The disadvantages are the long duration to repair the disk errors in case of failure, and the increased system boot time.
ReizerFS: It was the first system with the "Journaling" function incorporated into the Linux kernel. It is used in applications where performance with small files is significant (eg HTML). The main disadvantage is the difficulty of data recovery in case of loss.
EXT3: The third version of EXT integrated with the "Journaling" function. The EXT3, is the basic system for the latest Linux distributions available today. A great advantage is the compability with the EXT2 file system and the ability to convert an existing file system from EXT2 to EXT3 and the opposite. It provides high security, advanced reading algorithms and data recording outperform in even more specialized file systems.
What is the disk defragmentation?
The term "disk defragmentation" describes the process of consolidation of fragmented files that exist on your computer's hard drive. The fragmentation is a phenomenon that occurs naturally in a disk over time as you save, change, or delete files. During the save of the changes that have been made to an existing file, the new file is usually "placed" somewhere in the disk in a different place than the original file is located. As you continue to make changes, they are saved to even more different places. Over time, both the file and the hard disk itself become fragmented, resulting in the computer operation to slow as to open a file to be searched in many different places. Ie lose speed even wear of the disk (we have mechanical parts - magnetic read head and recording, where each search and the two heads, then operate and unnecessarily wear out the mechanism). Disk Defragmenter is a tool that makes rearranging the data on the hard disk and unites the fragmented files back to work more efficiently your computer.
The Hard Disk Drive (HDD) is a magnetic storage device. This device can be used in computers, digital camcorders, to portable MP3 players, etc. A HDD stores large amounts of data and the capacity of them starts from 160 GB and reaches up to 3 TB. For larger capacities that reach 8 TB (terabyte) multiple circuits are used in the form of bayonet assembly. The data access speed is faster than the DVD / R / RW, but much slower than the computer's memory. Hard drives are used in computers to store data, mainly programs and files that need to be maintained, in contrast to the RAM where the data is deleted by the power supply interruption. Also, all hard disks now have built-in cache (cache RAM) for temporary storage capacity starting from 8MB (minimum now) and reaches up to 64MB.Gradually, HDDs are giving way to solid state drives (SSD, Solid State Drive), which evolve rapidly mainly because of their low power consumption (due to the complete lack of motor), their speed and the relatively inexpensive cost of production. Since October 2010 due to the SSD technology is enabling the operation of NetBooks over about 10 hours continuously.
Description of HDD operation
A HDD consists a collection of plates (2-20), each of them has two writable surfaces. The stack of the plates is rotated from 3.600 to 5.400 revolutions per minute (RPM) (nowadays discs turning at over 7.200 rpm) and has a diameter ranging from more than one inch to more than 10 inches. Each disk surface is divided into concentric circles called spindles (tracks). Typically, there are 500 to 2.000 shells per surface. Each spindle is divided by the number of sectors (sectors) comprising the information. Each shaft may have 32 to 128 sectors and the sector is the smallest unit that can be read or written. To read and write information, the read / write heads must be moved in order to find over the place. The drive arms (disk arms) for each surface are connected and they are moving together, so that each arm is on the same shaft on each surface. The term cylinder (cylinder) is used to refer all shafts beneath the arms at a given point on all surfaces.
What is a file system?
The file system of an operating system, is defined as a set of procedures and data structures that can manage all the files of a computing device. The most important functions which can perform a file system are some key transactions with files (create, delete, read, change access rights etc.) and with directories (create, delete, transition, content previews, etc.
Some known file systems:
- FAT, FAT16, FAT32, NTSC (WINDOWS support)
- ext, ext2, ext3, reiserFS (LINUX support).
FAT (File Allocation Table): The FAT is the standard file system of Microsoft DOS operating system, which has been extended and incorporated in newer versions of Windows operating systems. The FAT was the core of the MS-DOS, Windows 3.11 and Windows 95 operating system. It was the first original FAT file system designed for Microsoft and it had 8 bit addressing. The FAT file system of 12 bit was used by Microsoft (in MS-DOS) and by IBM (in PC DOS) with floppy disk support. The FAT of 16 bit, a partition could not exceed 2 Gbytes disk space and the total number of lists, which are allowed, is quite limited for the requirements nowadays . The FAT16 is prone to fragmentation of files, which makes the accessing and the reading of files quite slow. From the second edition of Windows 95 FAT16 was replaced with FAT32 (32 bit addressing). Although the FAT32 was excelled in safety features, the FAT16 was faster in contrast with slow (by today's standards) processors of Windows 95. Another problem was also the conversion of a hard drive from FAT16 to FAT32, as it should be formatted. The problem was solved with the release of Windows 98, in which was included a conversion tool, that could hold the data intact without the need of formatting the disk.
NTSC: NTFS is the default file system of Windows O.S. since Windows XP came to the market. It is advantageous in many respects to the older FAT32 file system, such as: automatic restoration of correct functioning after some errors that occur in trays (which is not possible in FAT32), improved support for greater capacity and improved safety of data thanks the possibility of usage rights and encryption in order to access some files only to certain users that have been approved.
EXT (extended file system): A file system developed specially for Linux.
EXT2: The second version of EXT. It is offered for long high performance of the HDD, data security and low consumption of processing power. The disadvantages are the long duration to repair the disk errors in case of failure, and the increased system boot time.
ReizerFS: It was the first system with the "Journaling" function incorporated into the Linux kernel. It is used in applications where performance with small files is significant (eg HTML). The main disadvantage is the difficulty of data recovery in case of loss.
EXT3: The third version of EXT integrated with the "Journaling" function. The EXT3, is the basic system for the latest Linux distributions available today. A great advantage is the compability with the EXT2 file system and the ability to convert an existing file system from EXT2 to EXT3 and the opposite. It provides high security, advanced reading algorithms and data recording outperform in even more specialized file systems.
What is the disk defragmentation?
The term "disk defragmentation" describes the process of consolidation of fragmented files that exist on your computer's hard drive. The fragmentation is a phenomenon that occurs naturally in a disk over time as you save, change, or delete files. During the save of the changes that have been made to an existing file, the new file is usually "placed" somewhere in the disk in a different place than the original file is located. As you continue to make changes, they are saved to even more different places. Over time, both the file and the hard disk itself become fragmented, resulting in the computer operation to slow as to open a file to be searched in many different places. Ie lose speed even wear of the disk (we have mechanical parts - magnetic read head and recording, where each search and the two heads, then operate and unnecessarily wear out the mechanism). Disk Defragmenter is a tool that makes rearranging the data on the hard disk and unites the fragmented files back to work more efficiently your computer.
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