FAQ on the choice of components for the PC
FAQ on the choice of components for the PC
The choice of components for the PC пїЅ | FAQ
Rubricator
Post has been editedGloomy - 13.01.12, 12:48
The choice of components for the PC пїЅ | FAQ
Rubricator
Post has been editedGloomy - 13.01.12, 12:48
Rubricator
HDD
Power Supply
Video card
Motherboard
RAM
Keyboard
Uninterruptible Power Supply (UPS)
How to assemble a computer
Post has been editedGloomy - 13.01.12, 12:48
HDD
- HDD introductory article
- External HDD Standard Size
- External HDD case design
- HDD capacity
- Interface to connect external HDD
- Speed ​​and HDD Cache
- Cooling
- The most important thing in choosing an external HDD is the purpose of the device.
- Typical hard drive problems
- useful links
- SSD
- Hdd manufacturers
- HDD device
Power Supply
- What is a PC power supply?
- What should I look for when choosing a Power Supply?
- Power Supply Power
- Connectors on the power supply
- What you should not overpay
- Power Supply Power Calculators
- useful links
Video card
- Video card - introductory article.
- Video card device.
- Video card manufacturers.
- Some basic concepts in the world of three-dimensional graphics
- Video card selection
Motherboard
RAM
- What is RAM?
- Computer RAM - device and principle of operation
- Type of RAM
- Principles of memory selection
Keyboard
- Computer keyboard - general concepts
- Types of keyboards by type of connection.
- Multimedia Keyboards
- Key mechanism
- Keyboard selection
Uninterruptible Power Supply (UPS)
- Uninterruptible Power Supply (UPS) - general concepts
- How does an uninterruptible power supply (UPS) work?
- Types of Uninterruptible Power Supply (UPS)
- Characteristics of Uninterruptible Power Supply (UPS)
- Battery life
- Power factor. How to choose an uninterruptible power supply (UPS)?
How to assemble a computer
Post has been editedGloomy - 13.01.12, 12:48
HDD introductory article
How to choose a hard drive? What models are most reliable?
"Users often ask the question: what brand of hard drives (HDD) is better and more reliable, which one should be given preference when buying? Let's try to answer from the point of view of a repairman.
First of all, no brand is leading in terms of reliability. All rail manufacturers on the market have reached a roughly equal level of quality. This was facilitated by many years of intense competition, as well as related technologies and components (mechanical parts - heads, plates, etc. - are mostly purchased from third-party manufacturers). Companies that have faced serious problems have long since left the market, and the rest have given priority to reliability.
Huge efforts are spent on designing for fault tolerance. Firmware any railway actually is a real-time operating system, which is one of the main tasks - handling error conditions in the first place, tracking emerging surface defects (it is estimated that up to 80% of the code the firmware - is the realization of a defect-management algorithms). When positioning heads for writing and reading data used sophisticated error-correcting coding scheme and numerous locked loop with feedback. With regard to production, there reigns accounting and control (input validation components out functional assembly control, the output testing of finished railway with a record of each instance in the history database, and much more).
Moreover, companies are sharing technology! Many solutions that improve the reliability and performance of railways are not kept secret, and with the consent of the developer, they become the property of competitors. All this actually removes the question of choosing a brand. Another thing - the choice of the model range. Under the same brand today, you can find rulers for various purposes, in different price categories and, consequently, of unequal performance and reliability.
Descriptions of families, up to detailed specifications, are published on the official websites of manufacturers. Thus, the choice of the disc is primarily influenced by the needs and financial capabilities of the buyer. Often makes adjustments to the situation in the local market (not all models may be available), as well as changes in the production program. For all brands, it is updated at least twice a year, and already released lines are constantly being updated.
Further development includes both the debugging of the production process and change firmware versions. In some cases, the detection of serious problems in the firmware, manufacturers make a new version of the public, so that users self-stitched Railway bought before (nothing supernatural do not need, just run the downloaded file for execution). The new firmware will be corrected seen "bugs", but more often it serves to increase the performance and stability of the drive, including in difficult conditions (heat, vibration, etc.).
It follows the first piece of advice: do not take no great need the latest model just entering the market. New products may contain untested solutions in the design and firmware, and most importantly - are unstable in quality. There is considerable variation in the characteristics of the different batches, and frequent cases of direct marriage. On finishing process usually takes 3-4 months, so the first buyers perceived risk. Given that the railway has descended from the conveyor is on our shelves in an average of 3 months, it is wiser to look at the models that are available at least six months (to the same and the price had come down).
Do not neglect the Internet: it makes sense to look at the opinions of users in the thematic forums and guest books of computer companies. If the model of interest has problems over and over again, this is a reason to think about it. Equally alarming is the lack of feedback. In general, the experience of others is the best teacher.
Second Board - choose range suitable for the characteristics (productivity, heat, noise, etc.) to the requirements of a given job. Most manufacturers, aiming to cover all market segments, released specialized family optimized for a specific entry at the expense of others. Thus, the growing popularity of "green" hard disk drives with low power consumption - they do not differ quick access (spindle rotation speed of 5400 rev / min.), But a little heated and virtually no noise. This is the optimal solution for extremely quiet and compact PCs and consumer electronics (video recorders and so on.). At the other end of the spectrum - drives 7200 r / min with a powerful drive unit of magnetic heads and prefetching algorithms, "sharpened" by placing databases and system operating files, and unique WD VelociRaptor 10,000 rev / min with almost server performance...
Enterprise-class drives are designed for round-the-clock high load, they are resistant to overheating and have a high mean time to failure. This is achieved as a more stringent production control, and many new technologies, such as controlled altitude of the heads or the test read just recorded data. The considerable price in this case pays off high reliability.
Among the 2.5 ″ HD form factor, there are automobile models that are resistant to shocks and vibrations, can withstand temperatures from -30є to + 85є and elevations from -300 to 5000 m. An example is the Hitachi Endurastar family. The discs are focused on use as part of the onboard systems of cars, but they can be safely put in any portable device. Of course, high reliability costs money: “auto-drives” are three times more expensive than usual.
The third council - choose HDD capacity, based on their current and future needs. The form factor of 3.5 "can be divided into three categories of storage: single-platter, two-platter, trohplastinnye and more. The first category is best suited for placement of the operating system and application programs, with good performance, these drives are heated less than others and less likely to fail. Drive of the second category is worth to put in second PC and specifically to allocate to the database, gaming, and multimedia files. Finally, high-capacity drives - solution for special occasions not to mention the disproportionately high cost, they are quite capricious in operation. The refusal of the drive immediately block access to a wealth of data and backup understandably complicated.
The fourth and last tip - buy new discs in legal trading companies offering a full factory warranty (usually 3 or 5 years). Doubtful places (radio markets, etc.) are a haven of gray imports, used disks or after repairs. The reliability of such products is much lower, and warranty obligations are elusive. Minor savings can "
Post has been editedGloomy - 17.10.11, 21:08
How to choose a hard drive? What models are most reliable?
"Users often ask the question: what brand of hard drives (HDD) is better and more reliable, which one should be given preference when buying? Let's try to answer from the point of view of a repairman.
First of all, no brand is leading in terms of reliability. All rail manufacturers on the market have reached a roughly equal level of quality. This was facilitated by many years of intense competition, as well as related technologies and components (mechanical parts - heads, plates, etc. - are mostly purchased from third-party manufacturers). Companies that have faced serious problems have long since left the market, and the rest have given priority to reliability.
Huge efforts are spent on designing for fault tolerance. Firmware any railway actually is a real-time operating system, which is one of the main tasks - handling error conditions in the first place, tracking emerging surface defects (it is estimated that up to 80% of the code the firmware - is the realization of a defect-management algorithms). When positioning heads for writing and reading data used sophisticated error-correcting coding scheme and numerous locked loop with feedback. With regard to production, there reigns accounting and control (input validation components out functional assembly control, the output testing of finished railway with a record of each instance in the history database, and much more).
Moreover, companies are sharing technology! Many solutions that improve the reliability and performance of railways are not kept secret, and with the consent of the developer, they become the property of competitors. All this actually removes the question of choosing a brand. Another thing - the choice of the model range. Under the same brand today, you can find rulers for various purposes, in different price categories and, consequently, of unequal performance and reliability.
Descriptions of families, up to detailed specifications, are published on the official websites of manufacturers. Thus, the choice of the disc is primarily influenced by the needs and financial capabilities of the buyer. Often makes adjustments to the situation in the local market (not all models may be available), as well as changes in the production program. For all brands, it is updated at least twice a year, and already released lines are constantly being updated.
Further development includes both the debugging of the production process and change firmware versions. In some cases, the detection of serious problems in the firmware, manufacturers make a new version of the public, so that users self-stitched Railway bought before (nothing supernatural do not need, just run the downloaded file for execution). The new firmware will be corrected seen "bugs", but more often it serves to increase the performance and stability of the drive, including in difficult conditions (heat, vibration, etc.).
It follows the first piece of advice: do not take no great need the latest model just entering the market. New products may contain untested solutions in the design and firmware, and most importantly - are unstable in quality. There is considerable variation in the characteristics of the different batches, and frequent cases of direct marriage. On finishing process usually takes 3-4 months, so the first buyers perceived risk. Given that the railway has descended from the conveyor is on our shelves in an average of 3 months, it is wiser to look at the models that are available at least six months (to the same and the price had come down).
Do not neglect the Internet: it makes sense to look at the opinions of users in the thematic forums and guest books of computer companies. If the model of interest has problems over and over again, this is a reason to think about it. Equally alarming is the lack of feedback. In general, the experience of others is the best teacher.
Second Board - choose range suitable for the characteristics (productivity, heat, noise, etc.) to the requirements of a given job. Most manufacturers, aiming to cover all market segments, released specialized family optimized for a specific entry at the expense of others. Thus, the growing popularity of "green" hard disk drives with low power consumption - they do not differ quick access (spindle rotation speed of 5400 rev / min.), But a little heated and virtually no noise. This is the optimal solution for extremely quiet and compact PCs and consumer electronics (video recorders and so on.). At the other end of the spectrum - drives 7200 r / min with a powerful drive unit of magnetic heads and prefetching algorithms, "sharpened" by placing databases and system operating files, and unique WD VelociRaptor 10,000 rev / min with almost server performance...
Enterprise-class drives are designed for round-the-clock high load, they are resistant to overheating and have a high mean time to failure. This is achieved as a more stringent production control, and many new technologies, such as controlled altitude of the heads or the test read just recorded data. The considerable price in this case pays off high reliability.
Among the 2.5 ″ HD form factor, there are automobile models that are resistant to shocks and vibrations, can withstand temperatures from -30є to + 85є and elevations from -300 to 5000 m. An example is the Hitachi Endurastar family. The discs are focused on use as part of the onboard systems of cars, but they can be safely put in any portable device. Of course, high reliability costs money: “auto-drives” are three times more expensive than usual.
The third council - choose HDD capacity, based on their current and future needs. The form factor of 3.5 "can be divided into three categories of storage: single-platter, two-platter, trohplastinnye and more. The first category is best suited for placement of the operating system and application programs, with good performance, these drives are heated less than others and less likely to fail. Drive of the second category is worth to put in second PC and specifically to allocate to the database, gaming, and multimedia files. Finally, high-capacity drives - solution for special occasions not to mention the disproportionately high cost, they are quite capricious in operation. The refusal of the drive immediately block access to a wealth of data and backup understandably complicated.
The fourth and last tip - buy new discs in legal trading companies offering a full factory warranty (usually 3 or 5 years). Doubtful places (radio markets, etc.) are a haven of gray imports, used disks or after repairs. The reliability of such products is much lower, and warranty obligations are elusive. Minor savings can "
Ilya Zaydel, R.LAB
Post has been editedGloomy - 17.10.11, 21:08
External HDD Standard Size
External hard drives are mainly available in two sizes: desktop 3.5-inch and 2.5-inch portable. There are also over-portable and 1.8-inch, but they are not widespread.
3.5-inch devices contain one (or even several) standard hard drives for desktop PCs. Their main advantage is a larger volume. At the moment, the most common are models with capacity from 160 GB to 2 TB. Among the shortcomings it is necessary to note the need for an external power supply, large dimensions and weight.
2.5-inch external HDDs are carried inside the case of a hard disk in a “notebook” format, due to which they often do without an external power supply and are quite compact. The disadvantage is the higher cost of 1 GB of data and not a record maximum capacity. It is also believed that external 2.5-inch HDDs are generally more reliable than their larger counterparts.
Post has been editedGloomy - 17.10.11, 20:24
External hard drives are mainly available in two sizes: desktop 3.5-inch and 2.5-inch portable. There are also over-portable and 1.8-inch, but they are not widespread.
3.5-inch devices contain one (or even several) standard hard drives for desktop PCs. Their main advantage is a larger volume. At the moment, the most common are models with capacity from 160 GB to 2 TB. Among the shortcomings it is necessary to note the need for an external power supply, large dimensions and weight.
2.5-inch external HDDs are carried inside the case of a hard disk in a “notebook” format, due to which they often do without an external power supply and are quite compact. The disadvantage is the higher cost of 1 GB of data and not a record maximum capacity. It is also believed that external 2.5-inch HDDs are generally more reliable than their larger counterparts.
Post has been editedGloomy - 17.10.11, 20:24
External HDD case design
Given that the presence of the case and the interface unit is most often the only thing that distinguishes an external hard drive from an internal one, it is worthwhile to stay more closely when choosing these issues.
Cases of cheap external hard drives are made of plastic. They are lightweight, and are a simple protection from scratches and a small impact, which is enough for home use. However, for road conditions it is better to choose a stronger option.
The metal case adds weight to devices, but it significantly protects its insides from mechanical damage. Of course, this does not negate the need to handle the HDD carefully, especially during operation, but in any case gives a little more confidence in data integrity.
Most protected model for use in difficult conditions are made from combinations of metal and rubber. Inside the case there is padding that reduces the impact of shocks and bumps on a thin HDD mechanism. There device models, maximally protected from various impacts as dust, dirt, water, or falling. By purchasing this disc, with it you can safely go to a campaign, freely use it on the train, plane or car, or simply in the nature, without worrying too much for his safety. However, the cost of such models is much higher.
Given that the presence of the case and the interface unit is most often the only thing that distinguishes an external hard drive from an internal one, it is worthwhile to stay more closely when choosing these issues.
Cases of cheap external hard drives are made of plastic. They are lightweight, and are a simple protection from scratches and a small impact, which is enough for home use. However, for road conditions it is better to choose a stronger option.
The metal case adds weight to devices, but it significantly protects its insides from mechanical damage. Of course, this does not negate the need to handle the HDD carefully, especially during operation, but in any case gives a little more confidence in data integrity.
Most protected model for use in difficult conditions are made from combinations of metal and rubber. Inside the case there is padding that reduces the impact of shocks and bumps on a thin HDD mechanism. There device models, maximally protected from various impacts as dust, dirt, water, or falling. By purchasing this disc, with it you can safely go to a campaign, freely use it on the train, plane or car, or simply in the nature, without worrying too much for his safety. However, the cost of such models is much higher.
HDD capacity
Given the choice between 3.5 and 2.5-inch HDD in the first place determine what is more important to you: the compactness or volume. For infrequent backups, store the most important information and use as an additional drive on a trip or journey features a 2.5-inch HDD will be enough. If it is required the maximum amount, as well as the ability to connect to the network interface, then look at the so-called "external storage" on the basis of 3.5-inch drives. These systems have their own cooling, and support high-speed network interfaces and have the ability to replace hard drives to more capacious.
Small note:
Among users there is a perception that hard drive manufacturers "cheat" their customers, instead of the promised 500 GB of memory selling "only" 465 GB. At one time it even became a pretext for legal proceedings.
In fact, this is a feature of the binary system of calculus and habits of computer users. The prefixes "kilo", "mega", "giga" and "tera" in the C system are standardized, and are used to denote 1000, 1 000 000, 1 000 000 000, 1 000 000 000 000 units, respectively. In full compliance with them, hard drive manufacturers believe that 1 GB = 1,000,000,000 bytes.
At the same time, in computer technology the terms “kilo”, “mega” and “giga” are historically considered to be the powers of 2:
1 kilobyte = 210 = 1024 bytes;
1 megabyte = 220 = 1048576 bytes;
1 gigabyte = 230 = 1073741824 bytes;
etc.
It is in these values ​​that the operating systems are understood. As a result, when you purchase a disc that says “500 GB”, keep in mind that, from a software point of view, the amount of available space on it will be 465 GB. However, this convention has long been accustomed to, and do not pay attention to it.
Given the choice between 3.5 and 2.5-inch HDD in the first place determine what is more important to you: the compactness or volume. For infrequent backups, store the most important information and use as an additional drive on a trip or journey features a 2.5-inch HDD will be enough. If it is required the maximum amount, as well as the ability to connect to the network interface, then look at the so-called "external storage" on the basis of 3.5-inch drives. These systems have their own cooling, and support high-speed network interfaces and have the ability to replace hard drives to more capacious.
Small note:
Among users there is a perception that hard drive manufacturers "cheat" their customers, instead of the promised 500 GB of memory selling "only" 465 GB. At one time it even became a pretext for legal proceedings.
In fact, this is a feature of the binary system of calculus and habits of computer users. The prefixes "kilo", "mega", "giga" and "tera" in the C system are standardized, and are used to denote 1000, 1 000 000, 1 000 000 000, 1 000 000 000 000 units, respectively. In full compliance with them, hard drive manufacturers believe that 1 GB = 1,000,000,000 bytes.
At the same time, in computer technology the terms “kilo”, “mega” and “giga” are historically considered to be the powers of 2:
1 kilobyte = 210 = 1024 bytes;
1 megabyte = 220 = 1048576 bytes;
1 gigabyte = 230 = 1073741824 bytes;
etc.
It is in these values ​​that the operating systems are understood. As a result, when you purchase a disc that says “500 GB”, keep in mind that, from a software point of view, the amount of available space on it will be 465 GB. However, this convention has long been accustomed to, and do not pay attention to it.
Interface to connect external HDD
To connect external HDD to a computer, several interfaces are used, each of which has its own advantages and disadvantages. But before trying to make a choice between them, find out which of the following interfaces are supported by your PC or laptop, to which you will connect the drive.
If the HDD will be used with only one computer, then you can bet on the fastest of the interfaces for maximum performance. But for compatibility with any other computer, choose the most common interface (such as USB 2.0).
Usb
The USB 2.0 interface, originally developed for connecting peripherals to PCs, is currently supported by the vast majority of computers and laptops, as well as multimedia players, televisions, and other consumer electronics devices. Its theoretical bandwidth is 480 MB / s (about 60 MB / s), but in practice the data exchange rate does not exceed 30 MB / s. Despite this, such a value is still quite sufficient for data transfer or backup tasks.
The USB port on the main device has a USB Standard A connector. On the hard disk itself, it is made in a smaller format, most often USB Mini B. An adapter cable for connecting one device to another is supplied with an external HDD. Some models have a USB cable built into the case, which can be convenient (it’s just impossible to forget to take it along with the disk).
In 2008, a new version of USB ports appeared - high-speed USB 3.0 interface, which is 10 times faster than its predecessor, but still supports USB 2.0-compatible devices. By purchasing an external USB 3.0 hard drive, you can use both a regular USB 2.0 port and a high-speed USB 3.0, depending on which connector it is connected to. If necessary, and in the speed of work, and in compatibility such a choice may be the most justified.
LAN (Ethernet 10/100/1000).
The Ethernet network interface standard 10/100/1000 (the numbers indicate the maximum speed in MB / s) provides data access speed of 1.25 / 12.5 / 125 MB / s, respectively. But its main feature is not this. Unlike other interfaces, it is used to connect the drive to a local or external network as a standalone device that is accessible to all other PCs. This is very convenient when organizing a network or home media storage.
External hard drives with a LAN interface are usually more expensive than their counterparts, but this is fully justified, given that a computer is available for autonomous work in a local network inside the drive housing, even if it is rather simple. Managing such disks can be done from any PC on the network, using special software, or even just a web browser window. Some models even support remote control over the Internet from outside the local network.
Firewire.
The FireWire interface in its functions is in many ways similar to USB, and once upon a time was its competitor. It is a little less common, provides the speed of data exchange at the same level, however, it is designed to transfer large amounts of information and most often it can be found on Macintosh computers.
The FireWire 400 and 800 types, also referred to as IEEE 1394a and 1394b, provide data transfer rates of 400 and 800 MB / s, respectively. The peculiarity of these interfaces is the uniform distribution of the speed of information transfer when connecting multiple devices.
eSATA.
If all previous interfaces are quite versatile and were originally designed to connect a variety of devices, then eSATA is intended only for connecting hard drives. It provides a high maximum data transfer rate of 157 MB / s, but it requires an additional power adapter. This flaw is fixed in the eSATAp protocol - externally the connector of this interface is a “hybrid” of eSATA and USB ports.
Both eSATA and eSATAp have one major drawback - the maximum cable length is only 2 m. For USB and FireWire, the maximum length without loss of speed is about 5 m, and for Ethernet LAN it can be measured in tens and hundreds of meters.
Video connectors (HDMI, VGA, Composite).
Among the connectors on the external HDD can be found and quite unusual, for example, video interfaces HDMI, VGA or Composite. They are designed to transfer video stream in different resolutions to the display or TV, and the hard drive itself combines the functions and storage, and media player.
For users using an external HDD as a media library, this option can be convenient if it is necessary for its mobile use. In other cases, it will be more practical to have two separate devices for these purposes.
To connect external HDD to a computer, several interfaces are used, each of which has its own advantages and disadvantages. But before trying to make a choice between them, find out which of the following interfaces are supported by your PC or laptop, to which you will connect the drive.
If the HDD will be used with only one computer, then you can bet on the fastest of the interfaces for maximum performance. But for compatibility with any other computer, choose the most common interface (such as USB 2.0).
Usb
The USB 2.0 interface, originally developed for connecting peripherals to PCs, is currently supported by the vast majority of computers and laptops, as well as multimedia players, televisions, and other consumer electronics devices. Its theoretical bandwidth is 480 MB / s (about 60 MB / s), but in practice the data exchange rate does not exceed 30 MB / s. Despite this, such a value is still quite sufficient for data transfer or backup tasks.
The USB port on the main device has a USB Standard A connector. On the hard disk itself, it is made in a smaller format, most often USB Mini B. An adapter cable for connecting one device to another is supplied with an external HDD. Some models have a USB cable built into the case, which can be convenient (it’s just impossible to forget to take it along with the disk).
In 2008, a new version of USB ports appeared - high-speed USB 3.0 interface, which is 10 times faster than its predecessor, but still supports USB 2.0-compatible devices. By purchasing an external USB 3.0 hard drive, you can use both a regular USB 2.0 port and a high-speed USB 3.0, depending on which connector it is connected to. If necessary, and in the speed of work, and in compatibility such a choice may be the most justified.
LAN (Ethernet 10/100/1000).
The Ethernet network interface standard 10/100/1000 (the numbers indicate the maximum speed in MB / s) provides data access speed of 1.25 / 12.5 / 125 MB / s, respectively. But its main feature is not this. Unlike other interfaces, it is used to connect the drive to a local or external network as a standalone device that is accessible to all other PCs. This is very convenient when organizing a network or home media storage.
External hard drives with a LAN interface are usually more expensive than their counterparts, but this is fully justified, given that a computer is available for autonomous work in a local network inside the drive housing, even if it is rather simple. Managing such disks can be done from any PC on the network, using special software, or even just a web browser window. Some models even support remote control over the Internet from outside the local network.
Firewire.
The FireWire interface in its functions is in many ways similar to USB, and once upon a time was its competitor. It is a little less common, provides the speed of data exchange at the same level, however, it is designed to transfer large amounts of information and most often it can be found on Macintosh computers.
The FireWire 400 and 800 types, also referred to as IEEE 1394a and 1394b, provide data transfer rates of 400 and 800 MB / s, respectively. The peculiarity of these interfaces is the uniform distribution of the speed of information transfer when connecting multiple devices.
eSATA.
If all previous interfaces are quite versatile and were originally designed to connect a variety of devices, then eSATA is intended only for connecting hard drives. It provides a high maximum data transfer rate of 157 MB / s, but it requires an additional power adapter. This flaw is fixed in the eSATAp protocol - externally the connector of this interface is a “hybrid” of eSATA and USB ports.
Both eSATA and eSATAp have one major drawback - the maximum cable length is only 2 m. For USB and FireWire, the maximum length without loss of speed is about 5 m, and for Ethernet LAN it can be measured in tens and hundreds of meters.
Video connectors (HDMI, VGA, Composite).
Among the connectors on the external HDD can be found and quite unusual, for example, video interfaces HDMI, VGA or Composite. They are designed to transfer video stream in different resolutions to the display or TV, and the hard drive itself combines the functions and storage, and media player.
For users using an external HDD as a media library, this option can be convenient if it is necessary for its mobile use. In other cases, it will be more practical to have two separate devices for these purposes.
Speed ​​and HDD Cache
In most cases, the speed of reading and writing data to an external HDD is not affected by the speed of the disk itself, but by the bandwidth of the interface with which it is connected to the PC. However, different disks may vary in spindle speed - from 4,200 to 10,000 rpm. In practice, this parameter does not really matter for external HDDs, since in most cases the interface will be the bottleneck.
Partially, hard disk performance boosts cache memory — the larger its capacity, the better. At the moment, manufacturers are equipping hard drives with a cache size of 8-64 MB. In fact, this figure can also be ignored - for the same reasons as the speed of rotation.
In most cases, the speed of reading and writing data to an external HDD is not affected by the speed of the disk itself, but by the bandwidth of the interface with which it is connected to the PC. However, different disks may vary in spindle speed - from 4,200 to 10,000 rpm. In practice, this parameter does not really matter for external HDDs, since in most cases the interface will be the bottleneck.
Partially, hard disk performance boosts cache memory — the larger its capacity, the better. At the moment, manufacturers are equipping hard drives with a cache size of 8-64 MB. In fact, this figure can also be ignored - for the same reasons as the speed of rotation.
Cooling
Heat dissipation is a serious enemy of the hard disk. Excessive heat, which occurs during prolonged operation of the HDD, can shorten its lifespan. This is especially true for productive hard drives desktop format.
Some models of external hard drives are equipped with built-in fans for cooling. They reduce the thermal load on the disks of portable devices, but create additional noise.
Heat dissipation is a serious enemy of the hard disk. Excessive heat, which occurs during prolonged operation of the HDD, can shorten its lifespan. This is especially true for productive hard drives desktop format.
Some models of external hard drives are equipped with built-in fans for cooling. They reduce the thermal load on the disks of portable devices, but create additional noise.
The most important thing in choosing an external HDD is the purpose of the device.
If the external HDD is supposed to "not exit", then the dimensions and weight of the device should not particularly bother you. Focus on device capacity and the availability of all necessary interfaces.
For those who use an external hard drive as an addition to a laptop, especially on trips and business trips, the devices should be compact, support the most common interfaces, and if possible be shock resistant and protected from the hardships of life on the road.
But in any case, do not forget that the hard disk is an electromechanical device of very high accuracy, and you need to handle it with the utmost care. In order for the gigabytes of data recorded on it to be safe, you need to follow a number of simple rules:
Post has been editedGloomy - 17.10.11, 20:58
If the external HDD is supposed to "not exit", then the dimensions and weight of the device should not particularly bother you. Focus on device capacity and the availability of all necessary interfaces.
For those who use an external hard drive as an addition to a laptop, especially on trips and business trips, the devices should be compact, support the most common interfaces, and if possible be shock resistant and protected from the hardships of life on the road.
But in any case, do not forget that the hard disk is an electromechanical device of very high accuracy, and you need to handle it with the utmost care. In order for the gigabytes of data recorded on it to be safe, you need to follow a number of simple rules:
- Disconnecting the HDD from the PC is necessary only after a system shutdown - via the “Safely Remove Hardware” in the tray (lower right corner of the screen);
- Do not move, push, shake or hit the hard disk during operation;
- It is necessary to protect the HDD from falls and strong impacts even when it is off;
- Keep your external hard drive in a comfortable environment. Avoid temperature changes, do not leave it in places where it is too cold, too hot or too humid;
- For long-term storage (more than six months) of a disk without switching it on, it is recommended to update data. To do this, you need to save all the information from the disk, format it and re-write the data. There are also special programs for this purpose, to avoid rewriting and formatting;
- All your important information should ALWAYS be duplicated on multiple media (or online storage).
Post has been editedGloomy - 17.10.11, 20:58
Typical hard drive problems
"Bad" sectors.
This problem users face very often. Over time, or as a result of violation of the conditions, some sectors of the disc to stop reading. It can manifest itself in different ways: here and decrease the read / write speed, and damage data (including loss of information). The main danger of such a failure - the loss of information. Method of prevention is only one: to periodically test the disk surface with special tools (it is important that the program did not only read test, but also for the unused sectors recording test).
The causes of a malfunction are many - for example, factory defects, physical effects or voltage surges in a household electrical outlet. If the warranty period of the device is not over, you can replace it in the service center. Otherwise, it is worth testing the disk with a special utility that will mark sectors as failed. If the subsequent testing of new bad-blocks will not appear, such a hard drive can be used to store not very important information.
It should be noted that the emergence of bad sectors is not always associated with the surface of the disc. Sometimes it is due to problems with the firmware, but we'll talk about it later. Use a hard drive with "beaten" sectors for the storage of sensitive data can not be - you just copy the information to another drive as soon as you notice the appearance of a fault. If you fail to retrieve important files, do not attempt to recover the data - after the artisanal methods of "treatment" can be lost forever.
"Logical" faults.
Here we otnesom all high-level errors. Spoilage file system viruses, accidental removal of sections etc. In this case, the user can not get access to the recorded data, even though the drive is fully functional. If there is no important data on it was not, the easiest way to break the disk partitions and format again. To restore information from these devices, there are many utilities, however it is important to remember that the record on disk with the "logical" damages in any case impossible. There are several pitfalls. First, type ScanDisk program in such a situation completely useless - they are designed to work with logical partitions serviceable. Secondly, the mode can be enabled on your disk, when read with the error of logical sectors is reassigned a faultless; this may make it impossible to recover the data.
However, a similar effect - a phenomenon quite rare. More frequent problems because of the default included automated tests SMART. It checks the quality of the surface of the disc, and may also be sector remapping. If the hard drive with logical damage contains important data, it is better to turn to professionals (and for the professionals we understand the specialized company, and not a "programmer" with a set of public utilities), they will be able to read information from the disk so that the recording is not performed on him.
Problems with firmware.
Modern hard disk - rather complicated device. Its electronic part contains its own firmware, and with it, oddly enough, there are also problems. Recall, for example, the famous "Fly CC" (the name is associated with the error code "LED: 000000CC") suffering a series of Seagate 7200.11 (these drives have entered the market with numerous design flaws). Due to the destruction of the hard drive firmware becomes unstable: the read / write speed dropped, the hard drive could not be detected in the BIOS, etc.
Failures of the firmware can lead to the most unpredictable results, but they are treated the same way - by restoring the service information. This is done entirely by software, and the service technicians have two options: repair the hard drive with complete loss of all user data, or extract data from a faulty drive.
If you just need to repair the device, the service information is rewritten again, and then the full factory self-test procedure is started to completely calibrate the drive. If it is necessary to extract data, this method is unacceptable, and it takes a very long and painstakingly to restore service information without an absolute guarantee of the result. If the customer wants to get his data and repair the device, then after the restoration, you can proceed to repair.
It is clear that you can solve the problem with the firmware only in a specialized company. By the way, the appearance of bad sectors on the disk is not necessarily due to the physical state of the surface of the magnetic plates; it may be due to firmware failures. In this case, the service center specialists can repair the device.
Electronics malfunction.
Failure of the hard drive electronics may be associated with manufacturing defects, surges in household electrical outlet, and a bunch of other reasons. Often (but not always) with the diagnosis of damage can be visually: on the controller board, you can see the burned-out element. Winchester, as a rule, no signs of life - it is not defined utilities BIOS. Such a device must be repaired (although the repair is not always economically feasible), which can produce a qualified service center. The data in this case, as a rule, are not damaged, and their recovery is not required.
Wedge spindle and engine bearing wedge.
Determine the fault may be on the strong noise (hard drive emits a sound like screeching) or buzzing. Purely mechanical damage, often the problem arises after the fall of the device; We are particularly susceptible to this "disease" of increased capacity hard drives (they use three or more magnetic plates). Plate increases the load on the axle, and even a slight mechanical effects can lead to breakage. Plenty of options out there, and all of them disassemble it makes no sense - it is possible to recover data from such devices only with the use of specialized equipment, and even then not always (drive repair itself is not subject to).
The problem occurs with disks of all manufacturers, however, some unsuccessful models can be identified. Let's say that Seagate had a 7200.11 series, on which a motor spindle wedge appeared quite often (in addition to other breakdowns). Also, many Toshiba models are prone to similar problems - the cover covering their axles is thin and may deform over time. The grease gradually evaporates, and at one point the fluid bearing is wedged.
Failure of the magnetic heads unit.
As in the previous case, the user may suspect a malfunction in the hearing, when the disk appear extraneous clicks and tapping, and the hard drive can not be defined subroutines BIOS. Magnetic plate drives very accurately polished, and if the block of magnetic heads with them soprikosnotsya (usually it "floats" in the air flow produced by rotation of the plates), then separate them mechanics HDD can no longer due to strong molecular attraction. Thus there is a so-called "gash": head scratch the surface of discs. BIOS disk determines, but, naturally, it does not work.
For the occurrence of a malfunction, a strong mechanical effect on the hard drive is needed, however, in some Samsung models, the head may spontaneously strike the surface of the plates. Often there are problems with magnetic heads at Western Digital - they really do not like overheating. In addition, due to the design features (the axis with a block of magnetic heads is fixed by the device cover), WD hard drives do not tolerate mechanical impacts.
Winchesters with a malfunction of the magnetic heads unit cannot be repaired. Data from them can be recovered only in specialized companies and not always - if the heads just went out of order, then you can install a similar block from another hard drive. But if the surface of the magnetic plates is damaged, at best, the information will be partially restored.
Post has been editedGloomy - 17.10.11, 21:20
"Bad" sectors.
This problem users face very often. Over time, or as a result of violation of the conditions, some sectors of the disc to stop reading. It can manifest itself in different ways: here and decrease the read / write speed, and damage data (including loss of information). The main danger of such a failure - the loss of information. Method of prevention is only one: to periodically test the disk surface with special tools (it is important that the program did not only read test, but also for the unused sectors recording test).
The causes of a malfunction are many - for example, factory defects, physical effects or voltage surges in a household electrical outlet. If the warranty period of the device is not over, you can replace it in the service center. Otherwise, it is worth testing the disk with a special utility that will mark sectors as failed. If the subsequent testing of new bad-blocks will not appear, such a hard drive can be used to store not very important information.
It should be noted that the emergence of bad sectors is not always associated with the surface of the disc. Sometimes it is due to problems with the firmware, but we'll talk about it later. Use a hard drive with "beaten" sectors for the storage of sensitive data can not be - you just copy the information to another drive as soon as you notice the appearance of a fault. If you fail to retrieve important files, do not attempt to recover the data - after the artisanal methods of "treatment" can be lost forever.
"Logical" faults.
Here we otnesom all high-level errors. Spoilage file system viruses, accidental removal of sections etc. In this case, the user can not get access to the recorded data, even though the drive is fully functional. If there is no important data on it was not, the easiest way to break the disk partitions and format again. To restore information from these devices, there are many utilities, however it is important to remember that the record on disk with the "logical" damages in any case impossible. There are several pitfalls. First, type ScanDisk program in such a situation completely useless - they are designed to work with logical partitions serviceable. Secondly, the mode can be enabled on your disk, when read with the error of logical sectors is reassigned a faultless; this may make it impossible to recover the data.
However, a similar effect - a phenomenon quite rare. More frequent problems because of the default included automated tests SMART. It checks the quality of the surface of the disc, and may also be sector remapping. If the hard drive with logical damage contains important data, it is better to turn to professionals (and for the professionals we understand the specialized company, and not a "programmer" with a set of public utilities), they will be able to read information from the disk so that the recording is not performed on him.
Problems with firmware.
Modern hard disk - rather complicated device. Its electronic part contains its own firmware, and with it, oddly enough, there are also problems. Recall, for example, the famous "Fly CC" (the name is associated with the error code "LED: 000000CC") suffering a series of Seagate 7200.11 (these drives have entered the market with numerous design flaws). Due to the destruction of the hard drive firmware becomes unstable: the read / write speed dropped, the hard drive could not be detected in the BIOS, etc.
Failures of the firmware can lead to the most unpredictable results, but they are treated the same way - by restoring the service information. This is done entirely by software, and the service technicians have two options: repair the hard drive with complete loss of all user data, or extract data from a faulty drive.
If you just need to repair the device, the service information is rewritten again, and then the full factory self-test procedure is started to completely calibrate the drive. If it is necessary to extract data, this method is unacceptable, and it takes a very long and painstakingly to restore service information without an absolute guarantee of the result. If the customer wants to get his data and repair the device, then after the restoration, you can proceed to repair.
It is clear that you can solve the problem with the firmware only in a specialized company. By the way, the appearance of bad sectors on the disk is not necessarily due to the physical state of the surface of the magnetic plates; it may be due to firmware failures. In this case, the service center specialists can repair the device.
Electronics malfunction.
Failure of the hard drive electronics may be associated with manufacturing defects, surges in household electrical outlet, and a bunch of other reasons. Often (but not always) with the diagnosis of damage can be visually: on the controller board, you can see the burned-out element. Winchester, as a rule, no signs of life - it is not defined utilities BIOS. Such a device must be repaired (although the repair is not always economically feasible), which can produce a qualified service center. The data in this case, as a rule, are not damaged, and their recovery is not required.
Wedge spindle and engine bearing wedge.
Determine the fault may be on the strong noise (hard drive emits a sound like screeching) or buzzing. Purely mechanical damage, often the problem arises after the fall of the device; We are particularly susceptible to this "disease" of increased capacity hard drives (they use three or more magnetic plates). Plate increases the load on the axle, and even a slight mechanical effects can lead to breakage. Plenty of options out there, and all of them disassemble it makes no sense - it is possible to recover data from such devices only with the use of specialized equipment, and even then not always (drive repair itself is not subject to).
The problem occurs with disks of all manufacturers, however, some unsuccessful models can be identified. Let's say that Seagate had a 7200.11 series, on which a motor spindle wedge appeared quite often (in addition to other breakdowns). Also, many Toshiba models are prone to similar problems - the cover covering their axles is thin and may deform over time. The grease gradually evaporates, and at one point the fluid bearing is wedged.
Failure of the magnetic heads unit.
As in the previous case, the user may suspect a malfunction in the hearing, when the disk appear extraneous clicks and tapping, and the hard drive can not be defined subroutines BIOS. Magnetic plate drives very accurately polished, and if the block of magnetic heads with them soprikosnotsya (usually it "floats" in the air flow produced by rotation of the plates), then separate them mechanics HDD can no longer due to strong molecular attraction. Thus there is a so-called "gash": head scratch the surface of discs. BIOS disk determines, but, naturally, it does not work.
For the occurrence of a malfunction, a strong mechanical effect on the hard drive is needed, however, in some Samsung models, the head may spontaneously strike the surface of the plates. Often there are problems with magnetic heads at Western Digital - they really do not like overheating. In addition, due to the design features (the axis with a block of magnetic heads is fixed by the device cover), WD hard drives do not tolerate mechanical impacts.
Winchesters with a malfunction of the magnetic heads unit cannot be repaired. Data from them can be recovered only in specialized companies and not always - if the heads just went out of order, then you can install a similar block from another hard drive. But if the surface of the magnetic plates is damaged, at best, the information will be partially restored.
Evgeny Krestnikov
Post has been editedGloomy - 17.10.11, 21:20
SSD
SSD (Solid-State Disk), or solid-state disk - a new type of drives, the filling of which physically has nothing to do with traditional hard drives. In fact - this is an array of flash memory with a hard drive interface and access method. It connects to the PC SSD via traditional SATA or PATA interfaces and looks different from the HDD only in its more compact dimensions. SSD has all the advantages and disadvantages of flash memory.
The advantages of SSD in comparison with HDD include:
The disadvantages, in addition to the high price, include:
However, these advantages are already enough to make sense to equip business laptops with SSD-drives, as well as ultraportable models. Already today, some manufacturers-assemblers offer to install SSD instead of HDD in desktop PCs, but this replacement is not cheap yet.
A selection of links to reviews and articles on the choice of SSD
Post has been editedShoore - 24.03.13, 20:23
SSD (Solid-State Disk), or solid-state disk - a new type of drives, the filling of which physically has nothing to do with traditional hard drives. In fact - this is an array of flash memory with a hard drive interface and access method. It connects to the PC SSD via traditional SATA or PATA interfaces and looks different from the HDD only in its more compact dimensions. SSD has all the advantages and disadvantages of flash memory.
The advantages of SSD in comparison with HDD include:
- less access time (only with random reading);
- low power consumption;
- complete noiselessness;
- reduced size
- high impact resistance.
The disadvantages, in addition to the high price, include:
- slower read / write speed (large data arrays);
- smaller capacity (approximately 2-5 times).
However, these advantages are already enough to make sense to equip business laptops with SSD-drives, as well as ultraportable models. Already today, some manufacturers-assemblers offer to install SSD instead of HDD in desktop PCs, but this replacement is not cheap yet.
A selection of links to reviews and articles on the choice of SSD
Post has been editedShoore - 24.03.13, 20:23
Reason for editing: corrected link to "Collection"
Hdd manufacturers
Initially, the market was a large variety of hard drives, produces a variety of companies. Due to increasing competition and decreasing profit margins, most manufacturers were either bought by competitors, or transferred to other products. To date, most of all hard drives manufactured by only a few companies: Seagate, Western Digital, Samsung, as well as the former IBM unit for the production of Hitachi's drives. Fujitsu continues to produce hard drives for laptops-SCSI-disks, but left the mass market in 2001 (in 2009 the production of hard disk drives has been fully transferred to Toshiba [11] of the company). Toshiba is the major producer of 2,5- and 1.8-inch hard disk drives for laptop computers. Enough bright trace in the history of hard drives has left the company Quantum. One of the leaders in the production of discs is the company Maxtor. In 2001, the division bought Maxtor hard drives of Quantum. In 2006, the merger took place on Seagate and Maxtor. In the mid-1990s, there was Conner company that bought Seagate. In the first half of 1990 there was a firm Micropolis, it produces a very expensive premium-class drives. But with the release of the industry's first hard drive at 7200 rev / min it was used substandard main shaft bearings supplied by Nidec, and Micropolis suffered fatal losses for refund, went bankrupt and was bought out completely by Seagate. In spring 2011 the production of hard Hitachi bought the company Western Digital drives. At the same time Samsung has sold its HDD unit Seagate. In 2011 there were 3 manufacturer - Seagate, Western Digital and Toshiba.
Currently, in connection with the promotion of external storage to the market and the development of SSD-type technologies, the number of firms offering ready-made solutions has increased again.
Post has been editedGloomy - 21.10.11, 10:52
Initially, the market was a large variety of hard drives, produces a variety of companies. Due to increasing competition and decreasing profit margins, most manufacturers were either bought by competitors, or transferred to other products. To date, most of all hard drives manufactured by only a few companies: Seagate, Western Digital, Samsung, as well as the former IBM unit for the production of Hitachi's drives. Fujitsu continues to produce hard drives for laptops-SCSI-disks, but left the mass market in 2001 (in 2009 the production of hard disk drives has been fully transferred to Toshiba [11] of the company). Toshiba is the major producer of 2,5- and 1.8-inch hard disk drives for laptop computers. Enough bright trace in the history of hard drives has left the company Quantum. One of the leaders in the production of discs is the company Maxtor. In 2001, the division bought Maxtor hard drives of Quantum. In 2006, the merger took place on Seagate and Maxtor. In the mid-1990s, there was Conner company that bought Seagate. In the first half of 1990 there was a firm Micropolis, it produces a very expensive premium-class drives. But with the release of the industry's first hard drive at 7200 rev / min it was used substandard main shaft bearings supplied by Nidec, and Micropolis suffered fatal losses for refund, went bankrupt and was bought out completely by Seagate. In spring 2011 the production of hard Hitachi bought the company Western Digital drives. At the same time Samsung has sold its HDD unit Seagate. In 2011 there were 3 manufacturer - Seagate, Western Digital and Toshiba.
Currently, in connection with the promotion of external storage to the market and the development of SSD-type technologies, the number of firms offering ready-made solutions has increased again.
Post has been editedGloomy - 21.10.11, 10:52
HDD device
HDD(Hard Disk Drive, HDD, HMDD; in simple terms screw, hard, harddisk) - a storage device that has a very high capacity and is characterized by a fixed hard base. The basis for hard drives is usually aluminum or ceramic. It is the main data storage in almost all computers.
"A modern hard drive consists of the following main parts: the electronics board, the HDA and the software part.
HDA serves to protect the pack and fixing a magnetic disk - and media block of magnetoresistive heads (BMG), whose operation is to use materials that change their electrical resistance when changing the intensity of the ambient magnetic field. Magnetic disks are covered with magnetically sensitive layer, which is a carrier of information. It information represents the magnetic fields generated the smallest portions of the deposited layer. Readhead entering the field produced by the magnetic coating portion, it generates an electrical signal as a conductor located in a magnetic field. This signal is suitably processed and transmitted further in the interface.
On some hard drives, there are windows for a servo-rim boom (a device for recording servo-marking on the drive plates), covered with a durable foil material. The germoblock is filled with dust-free air, which communicates with the environment through special compensation holes, closed by filters, to equalize the pressure inside the containment zone.
As shown in the figure, a head attached to the metal yoke, movable relative to the magnetic disk. During operation of the engine rotating magnetic disks creates an air stream which defines an "air cushion" between the head and the surface. When stopping spindle motor automatically rocker (usually pressurized air stream from the still rotating disc) is given in the so-called parking position, in which it is fixed by a special lock or a magnetic lock. In this position of the head are derived from the work area to prevent possible contact between the yoke and the disc surface, thereby protecting the vulnerable work surface. "Parking" zone is usually closer to the spindle axis. But there are exceptions, in particular, on the hard drive of laptops parking area is located on the special parking racks located outside the plates.
Positioner (device positioning read / write heads over the disk) from the yoke is moved along the magnetic disk in modern hard drives via an electromagnet. The aft actuator coil is covered from above and below is rigidly fixed to the HDA magnetic plates, which serve as the stator. When a current is passed through the coil positioner coil begins to deviate to a certain acceleration, and its deflection direction can be changed changing the current direction in the coil positioner. This control scheme is called Voice Coil.
Inside the containment located preamplifier chip \ Switching (preamplifier, a switch). This, at first glance, strange, its location (inside the HDA, and not on the circuit board, next to the rest of the electronics) is explained very simply: the preamplifier should be placed as close as possible to the reading and writing heads to reduce tract head-preamplifier and reduce the suggestive he interference. With preamp signal is on the ribbon cable to the PCB, which is converted into a form in which it appears to the IDE controller computer motherboard.
In real work, the hard drive has to read data from the surface. To do this, he must know where the heads are at the moment and where he needs to move them. For this purpose, a servo information unique for each track and each data sector is recorded on the disk surface.
The electronics board consists of the following main components: a central processor, a RAM module, a ROM chip (on modern drives, the ROM is integrated into the processor, a so-called mask ROM), a spindle motor and BMG control chip, a power connector and an interface connector.
We should also stop at the drive's firmware. It usually consists of two parts: the original uploader and the actual main program (overlays translator with a defect-lists, the SMART modules, modules factory calibration and self-test, logs, and so on.). The loader is located mainly on the electronics board in a processor, ROM +. Making the board and start the engine untwisted to the desired speed, the firmware on the positions of the head servorazmetke and tries to read the service information. If it happened without a glitch, the disk recalibrates and reports on readiness for the interface.
Of course, this article is very overview and can not cover all the nuances and subtleties of the structure of a modern hard drive, which undoubtedly is a very complex device, essentially resembling a computer in miniature. "
Post has been editedGloomy - 17.10.11, 22:08
HDD(Hard Disk Drive, HDD, HMDD; in simple terms screw, hard, harddisk) - a storage device that has a very high capacity and is characterized by a fixed hard base. The basis for hard drives is usually aluminum or ceramic. It is the main data storage in almost all computers.
"A modern hard drive consists of the following main parts: the electronics board, the HDA and the software part.
HDA serves to protect the pack and fixing a magnetic disk - and media block of magnetoresistive heads (BMG), whose operation is to use materials that change their electrical resistance when changing the intensity of the ambient magnetic field. Magnetic disks are covered with magnetically sensitive layer, which is a carrier of information. It information represents the magnetic fields generated the smallest portions of the deposited layer. Readhead entering the field produced by the magnetic coating portion, it generates an electrical signal as a conductor located in a magnetic field. This signal is suitably processed and transmitted further in the interface.
On some hard drives, there are windows for a servo-rim boom (a device for recording servo-marking on the drive plates), covered with a durable foil material. The germoblock is filled with dust-free air, which communicates with the environment through special compensation holes, closed by filters, to equalize the pressure inside the containment zone.
As shown in the figure, a head attached to the metal yoke, movable relative to the magnetic disk. During operation of the engine rotating magnetic disks creates an air stream which defines an "air cushion" between the head and the surface. When stopping spindle motor automatically rocker (usually pressurized air stream from the still rotating disc) is given in the so-called parking position, in which it is fixed by a special lock or a magnetic lock. In this position of the head are derived from the work area to prevent possible contact between the yoke and the disc surface, thereby protecting the vulnerable work surface. "Parking" zone is usually closer to the spindle axis. But there are exceptions, in particular, on the hard drive of laptops parking area is located on the special parking racks located outside the plates.
Positioner (device positioning read / write heads over the disk) from the yoke is moved along the magnetic disk in modern hard drives via an electromagnet. The aft actuator coil is covered from above and below is rigidly fixed to the HDA magnetic plates, which serve as the stator. When a current is passed through the coil positioner coil begins to deviate to a certain acceleration, and its deflection direction can be changed changing the current direction in the coil positioner. This control scheme is called Voice Coil.
Inside the containment located preamplifier chip \ Switching (preamplifier, a switch). This, at first glance, strange, its location (inside the HDA, and not on the circuit board, next to the rest of the electronics) is explained very simply: the preamplifier should be placed as close as possible to the reading and writing heads to reduce tract head-preamplifier and reduce the suggestive he interference. With preamp signal is on the ribbon cable to the PCB, which is converted into a form in which it appears to the IDE controller computer motherboard.
In real work, the hard drive has to read data from the surface. To do this, he must know where the heads are at the moment and where he needs to move them. For this purpose, a servo information unique for each track and each data sector is recorded on the disk surface.
The electronics board consists of the following main components: a central processor, a RAM module, a ROM chip (on modern drives, the ROM is integrated into the processor, a so-called mask ROM), a spindle motor and BMG control chip, a power connector and an interface connector.
We should also stop at the drive's firmware. It usually consists of two parts: the original uploader and the actual main program (overlays translator with a defect-lists, the SMART modules, modules factory calibration and self-test, logs, and so on.). The loader is located mainly on the electronics board in a processor, ROM +. Making the board and start the engine untwisted to the desired speed, the firmware on the positions of the head servorazmetke and tries to read the service information. If it happened without a glitch, the disk recalibrates and reports on readiness for the interface.
Of course, this article is very overview and can not cover all the nuances and subtleties of the structure of a modern hard drive, which undoubtedly is a very complex device, essentially resembling a computer in miniature. "
A. Makarov aka Robin from Sherwood
Post has been editedGloomy - 17.10.11, 22:08
What is a PC power supply?
The power supply unit - the intended device to the DC component PC. The choice of the power supply depends directly on stable operation of the computer. Many people want to save on the purchase of the block, the result - not start the computer or run a tenth time, plus the remaining parts wear out faster. In particular, hard drives fail after being burned is not an expensive power supply. Therefore, do not skimp on the block, a good power supply is the basis buduyuschih upgrades.
The power supply unit - the intended device to the DC component PC. The choice of the power supply depends directly on stable operation of the computer. Many people want to save on the purchase of the block, the result - not start the computer or run a tenth time, plus the remaining parts wear out faster. In particular, hard drives fail after being burned is not an expensive power supply. Therefore, do not skimp on the block, a good power supply is the basis buduyuschih upgrades.
What should I look for when choosing a Power Supply?
- "When choosing a power supply unit, its weight should also be taken into account." A little strange phrase. But, as it turned out, the more weight - the better quality of the power elements or the cooling system will be better than that of competitors.
- It is necessary to treat carefully such indicator as voltage stability (on all lines 5, 12, and 3 - volt). When voltage drops, the system “brakes”.
- Power (W) - it is necessary to select a power supply unit with a certain margin, for a specific computer, this “margin” will serve to further update the components, as well as save it from overloads, which will prolong the service life (at maximum load, wear and tear is in progress).
- Cooling system (CO) - it is important to place the cooler / coolers (rpm, noise level, air flow), radiator dimensions.
- Modular connection - can be both a plus and a huge disadvantage. With this connection it is better to organize the air flow inside the case, but in a cheap version such connection leads to huge losses of power and voltage stability.
- A modern standard for connecting motherboards - ATX 24 + 8 pin, for video cards - 6 (6 + 2) pin replaced 20 + 4 pin, to ensure the stability of the PC even under extreme loads.
- If possible, you should pay attention to the quality of the installed power elements and assembly inside the power supply.
Power Supply Power
Any computer power supply has several tires, in other words, produces different voltage. This is 12, 5 and 3.3, plus some auxiliary lines. Again, it is understood that each tire has a certain maximum current limiting its capacity. It is also clear that it is the total capacity of all tires and generates the final value. These figures indicate almost always, and not only the final value, but also the distribution formula for explaining the origin of the figure of 500 W, for example. It would seem - everything as simple as possible. But no, this is where manufacturers are trying a bit of spice capabilities of the product.
Referring only to power, in a nutshell, you can say this: any more or less modern computer power supply load in the main bus + 12V, current consumption of the bus + 5V and + 3.3V is relatively small, and the total capacity of more than 100 watts of these lines is not required. Manufacturers cheat because they indicate the total capacity, making the contribution of tires + 5V and + 3.3V at 200 watts. If you see such a trick, do not hesitate to take away from the proposed value of all that is in the amount of hypothetical possibilities of the above two lines exceeds 120 ... 130 Watt. Sometimes this "adjustment" makes the claimed 500 almost 400 watts. Cobiraya even a very powerful computer, you can safely limited power supply of 750 watts, while receiving a good stock "for growth." Buy PD 1000, 1200, 1300, etc. It should be only in the case of constructing a system with extraordinary good overclocking or simply for moral satisfaction.
Any computer power supply has several tires, in other words, produces different voltage. This is 12, 5 and 3.3, plus some auxiliary lines. Again, it is understood that each tire has a certain maximum current limiting its capacity. It is also clear that it is the total capacity of all tires and generates the final value. These figures indicate almost always, and not only the final value, but also the distribution formula for explaining the origin of the figure of 500 W, for example. It would seem - everything as simple as possible. But no, this is where manufacturers are trying a bit of spice capabilities of the product.
Referring only to power, in a nutshell, you can say this: any more or less modern computer power supply load in the main bus + 12V, current consumption of the bus + 5V and + 3.3V is relatively small, and the total capacity of more than 100 watts of these lines is not required. Manufacturers cheat because they indicate the total capacity, making the contribution of tires + 5V and + 3.3V at 200 watts. If you see such a trick, do not hesitate to take away from the proposed value of all that is in the amount of hypothetical possibilities of the above two lines exceeds 120 ... 130 Watt. Sometimes this "adjustment" makes the claimed 500 almost 400 watts. Cobiraya even a very powerful computer, you can safely limited power supply of 750 watts, while receiving a good stock "for growth." Buy PD 1000, 1200, 1300, etc. It should be only in the case of constructing a system with extraordinary good overclocking or simply for moral satisfaction.
Pilyuchenko Dmitry Eduardovich
Connectors on the power supply
When choosing a power supply, special attention should be paid to the presence of modern connectors in the right quantity and length of cables. It is believed that for a normal computer assembly in a small case it is necessary that the minimum length of cables to the first connectors be at least 35 cm. Better when this distance is 40 ... 45 cm.
Post has been editedGloomy - 17.10.11, 22:59
When choosing a power supply, special attention should be paid to the presence of modern connectors in the right quantity and length of cables. It is believed that for a normal computer assembly in a small case it is necessary that the minimum length of cables to the first connectors be at least 35 cm. Better when this distance is 40 ... 45 cm.
- Main Power Connector 20 + 4 pin 24pin connector for motherboard (main connector). It may be monolithic or four detachable contacts. Always only one.
- + 12V Power ConnectorSquare 4-pin socket for motherboard. As a rule, one is required, at least two.
- EPS12V Power ConnectorRight-angled 8-pin connector for server motherboards. Required in case of high power consumption. As a rule, it is installed in a power supply unit conforming to the EPS12V standard.
- PCI Express Power ConnectorRectangular 6-touch connector for video cards. Used to power modern graphics cards.
- Peripheral Power ConnectorConventional 4-pin connector (molex) for additional devices. It is used to power peripheral consumers.
- SATA Power ConnectorFlat connector for modern hard drives and optical drives.
- Floppy Drive Power Connector4-pin connector for drives.
Pilyuchenko Dmitry Eduardovich
Post has been editedGloomy - 17.10.11, 22:59
What you should not overpay
Split lines + 12V (Dual + 12V output circuits)It is essentially a virtual division since actually there is no separation. In block set one RF transformer which is supplied with 12 volt. We repeat once again: one! The lines were divided in order to power, which is present on the freely available slots, does not exceed a certain level that is required by some standards. For the user, it does not matter how many alleged tire (+ 12V1, + 12V2, + 12V3, + 12V4, etc.) has a source, whether they at least two, at least eight! Important only their total capacity! On the computer, you are not affected in any way.
Support for dual and quad-core processors and video cards in dual mode (Quad / Dual core CPU support, SLI and CrossFire support)- the myth of pure water: as the most powerful processors with any number of cores, and any video card in any mode does not impose any additional requirements on the power supply unit, except for the need to provide the necessary power. If the power matches, and the necessary connectors are there, then any power supply will work well, regardless of whether there are these stickers on its box or not.
RoHS (Reduction of Hazardous Substances)- the use of components containing no hazardous substances in order to reduce environmental pollution. The power supply unit with a label elements to be installed with a reduced lead content, as well as to be used lead-free soldering. However, running a BP well, not better compared to traditional solutions, when there is a priori more expensive. In other words, the presence of this logo shows only care about the environment the manufacturer if you want to overpay a little for it - is commendable. But winning this no no.
Next are the types of protection, which are praised by some manufacturers as advantages, but such protection requires the use of the ATX standard, so they are absolutely in any BP.
Short circuit protection (SCP).
Short-circuit protection (CZ) on the output connectors. However, it is strictly obligatory and is always present even in prehistoric specimens. Talking about its presence is about how to say that there is an input connector in the power supply: if you don’t say so, it will not disappear anyway.
Overpower protection (OPP)
It is a protection against total overload on tires. This type of protection is mandatory, so there is always.
Overcurrent protection (OCP)
It is a current protection when the bus current exceeds the allowable (established). Protection is not mandatory, although it is used almost everywhere.
Overvoltage protection (OVP)
Protection triggered when the voltage is much higher than permissible, for example, when the power supply fails. It is mandatory, therefore it is always implemented.
Undervoltage protection (UVP)
The same thing only works when the voltage drops.
Split lines + 12V (Dual + 12V output circuits)It is essentially a virtual division since actually there is no separation. In block set one RF transformer which is supplied with 12 volt. We repeat once again: one! The lines were divided in order to power, which is present on the freely available slots, does not exceed a certain level that is required by some standards. For the user, it does not matter how many alleged tire (+ 12V1, + 12V2, + 12V3, + 12V4, etc.) has a source, whether they at least two, at least eight! Important only their total capacity! On the computer, you are not affected in any way.
Support for dual and quad-core processors and video cards in dual mode (Quad / Dual core CPU support, SLI and CrossFire support)- the myth of pure water: as the most powerful processors with any number of cores, and any video card in any mode does not impose any additional requirements on the power supply unit, except for the need to provide the necessary power. If the power matches, and the necessary connectors are there, then any power supply will work well, regardless of whether there are these stickers on its box or not.
RoHS (Reduction of Hazardous Substances)- the use of components containing no hazardous substances in order to reduce environmental pollution. The power supply unit with a label elements to be installed with a reduced lead content, as well as to be used lead-free soldering. However, running a BP well, not better compared to traditional solutions, when there is a priori more expensive. In other words, the presence of this logo shows only care about the environment the manufacturer if you want to overpay a little for it - is commendable. But winning this no no.
Next are the types of protection, which are praised by some manufacturers as advantages, but such protection requires the use of the ATX standard, so they are absolutely in any BP.
Short circuit protection (SCP).
Short-circuit protection (CZ) on the output connectors. However, it is strictly obligatory and is always present even in prehistoric specimens. Talking about its presence is about how to say that there is an input connector in the power supply: if you don’t say so, it will not disappear anyway.
Overpower protection (OPP)
It is a protection against total overload on tires. This type of protection is mandatory, so there is always.
Overcurrent protection (OCP)
It is a current protection when the bus current exceeds the allowable (established). Protection is not mandatory, although it is used almost everywhere.
Overvoltage protection (OVP)
Protection triggered when the voltage is much higher than permissible, for example, when the power supply fails. It is mandatory, therefore it is always implemented.
Undervoltage protection (UVP)
The same thing only works when the voltage drops.
Pilyuchenko Dmitry Eduardovich
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