It is known that hard disks are equipped with their own buffer memory of a relatively small amount. The buffer is used as the built-in cache memory for performing read and write operations, allowing to optimize the operation and minimize the time required to access the magnetic plates. For example, when there is free space in the buffer, the controller can temporarily place the data to be written there and wait for a convenient time when there are no requests from the system (host). When executing read requests, the controller stores the last read data in case the host requests them again - then you do not need to access the disk again. The controller often performs read-ahead reading, trying to predict the following host requests, and the data read in this way also puts it in the buffer. It turns out that the buffer is used by the hard disk constantly, and its role is very important.
This diameter is a good indicator of the mass of the plates and, consequently, of consumption. The consequence of this is that power affects consumption, since many plates are often synonymous with large capacity disks, and larger trays will have a larger capacity than small trays.
Thus, the restriction of energy consumption is difficult and can only transfer indirect funds. Most disk controllers use algorithms to pause playback or stop the rotation of trays in the absence of access to the disk. The query queue allows you to implement these algorithms. These algorithms slow or speed up the rotation speed of the trays depending on the workload on the hard disk. If there is a lot of work on the hard disk, the speed of the trays will increase to the maximum value, otherwise the speed of the trays will decrease to the minimum value. when the buffer is full: the more the queue is filled, the faster the trays will be.
Manufacturers of hard drives have always sought to increase the amount of buffer memory. Today it is easier to do this, since conventional synchronous dynamic memory (SDRAM) chips, and they are used in hard disks, are quite inexpensive. In the late 90's desktop hard drives were equipped with a 512 KB buffer, then most models received 2 MB of memory, and today the most common hard drives with 8 MB buffer. However, there is no limit to perfection: WD has updated its mass line of Caviar SE hard drives, adding it to the Caviar SE16 models. The main difference, as you've guessed, is the doubled amount of buffer memory.
Show all peripherals. They are the only ones that make the program wait for its end. If checked, the device performs a function associated with the control, before returning to the management of the program. If the check box is not selected, the device simply checks the command before returning directly to the program control. The program is then asked to determine whether the device completed the task associated with the sent command.
Typically, the peripheral device simply checks the control and returns control to the program; The program then requests the periphery to find out if it is complete and updates the progress as it progresses. The usual method is to access it along the way.
Why do we need 16 MB?
It would seem that the larger the amount of buffer memory, the higher the performance of the hard disk. The controller will be able to place more data into the buffer, which means that it will rarely apply to magnetic plates. However, not everything is as simple as it seems at first glance.
Caching algorithms usually use the associative search method to determine if the required data is in the buffer. To increase the amount of data stored in the cache, either increase the volume of one block (cache line) or increase the number of rows. And this is fraught with the appearance of additional problems with associative search and data exchange with the cache.
- Uses a transmission length of 64 KB.
- Selects a transmission length of 32 KB or 64 KB.
However, for a hard disk, the caching rate is not so important, since it is in any case negligible compared to the delays in accessing the magnetic medium. It's another matter whether the controller really needs additional memory. It is possible that the hard disk is not so loaded with work to fully use all available buffer space. For example, if you simply copy and load programs, you do not need to cache anything, since the data is read only once. But when working in a server environment, when requests arrive randomly and continuously, a large buffer is a significant plus for the hard drive. Actually, that's why server hard disks were always equipped with a buffer of at least 8 MB. But the speed of reading and access is more important in a desktop computer than the efficiency of buffering.
The quality of the engraving will probably not be affected. This setting adjusts the size of the buffer memory. The buffer of the recording device is internal to the peripheral device and can not be changed. Adjust the buffer size from 1 MB to 512 MB.
Enable buffer overlay. When the "main" buffer is cleared and the "peripheral" buffer is cleared, the buffers are filled and waiting for: - the buffer to be filled; - the activity of the hard disk reaches the set value for the "length" of the average disk queue. Increasing the buffer size will not make it fill up faster, instead, more gaskets will be filled. What would you do to avoid a buffer dump is to regularly defragment your hard drive to close all unused programs, rather than allowing large programs to run during the etching process.
(It's true that we will not forget about NCQ technology.With it, the hard drive can manage the queue of requests, changing the order of their servicing.Since in this case the nature of access to the medium also changes, additional buffering can help in improving performance. pore does not know how to use NCQ, because only support from the hard drive is not enough here).
Old recorders do not support temporary stopping of engraving and gaskets. Overlap threshold. These settings can be changed only if the option "Enable Buffer Overlay" was checked. If this is not the case, these adjustments will not change, and there is no reason why the filling mechanism should enter the game too quickly. Be sure to increase the size of the main buffer, if your machine almost does not fill it.
When the main buffer and burner buffer fall below the set value, the program expects the main buffer to be full before restarting the recording. If the main buffer falls below the set value, the recorder will wait for the buffers to be filled in to resume recording. Device If the recorder's buffer drops below the set value, it will wait for the buffers to be full to resume recording. The value is the average value for all peripherals, not just the source drive. However, some explanations may remain somewhat unclear to you.
It turns out that a large amount of buffer is unlikely to have a significant impact on the overall speed. Putting a higher-capacity chip is not enough to improve performance. Developers should not only recycle the microcode, but also improve the speed of media read / write and the bandwidth of the interface.
Caviar SE16. Design Features
If there are any doubts or inaccuracies, do not hesitate to ask a question at the bottom of the article. Virtual memory is a second RAM located on a hard disk that actively supports physically installed RAM.
The main task was to manually allocate more RAM to high-performance applications, without paying money for the rack for the rack. However, it also had the feature of sacrificing the performance of your computer, because our old systems controlled this virtual memory archaic. Nevertheless, a significant performance gain can be achieved by a good parametrization of this memory.
We managed to compare the model WD2500KS, included in the line Caviar SE16, with the model WD2000JS from the "standard" Caviar SE line. As it turned out, they have a minimum of differences: the markings of the airlock, connectors, electronics boards coincide. Even the microcode version is the same. Consequently, the developers of WD used the old technology, simply replacing one memory chip with another one.
The purpose of this action is to free memory and allow the system to continue to function properly. Then the screen is filled with a lot of information. The RAM used consists of wired memory, active and inactive. Finally, unused memory. - Line 6 shows the management of your virtual memory. Here, pages and screens are important.
If you start the application and exit it, you will notice that there is less RAM on your computer than previously available. That's why applications run much faster at the second boot, but when there is no more available memory, the system then makes some pop-ups to free RAM, and this action destroys the performance of your machine.
For those who are not aware of the features of WD hard drives, let's report the following. This manufacturer applies only proven technology and is especially concerned about protecting the discs from damage. The design of the hermetic unit is standard: a massive body and a flat top cover are hermetically connected, on the cover there is a vent on the cover. But the electronics board is traditionally turned inwards by chips and pressed against the body, there is a thermo-conductive gasket. This method allows you to protect the chips from overheating and external influences. Power connectors two - a standard 4-pin and a new flat, in accordance with the requirements of Serial ATA. To protect the Serial ATA interface connector from accidental disconnection, WD suggests using a special SecureConnect cable that has latches.
This first snapshot shows that 35 operations have been performed on my computer at the moment. It also shows that out of 320 MB of physical memory on my computer 245 MB is busy and 74.9 MB is free. In addition, only 5, 73 MB is available, and the rest is used by the management of 13 applications and also the system. 48 operations are carried out, including 18 applications. Now do the same on your computer and watch with desperation what happens when the system starts creating pages.
The advantage of a dedicated swap partition. Virtual memory is on your hard drive, but does not take any specific position, which means that the information in your virtual memory is copied anywhere on the hard drive. at a time, dramatically speeding up your computer's performance, especially when you have 2 hard disks, the first disk running on the system and applications, and the second is the swap partition.
The Caviar SE16 series is only available with Serial ATA interface support. Moreover, the hard disk controller supports the "second speed" of 3 GB / s (300 MB / s). Other technologies, in particular, NCQ, have not yet been implemented - here WD lags behind other manufacturers.
Declared Hard Drive Parameters WD Caviar SE / SE16 Create a dedicated swap partition. First of all, what size do you want to allocate for this swap partition? Note that this section works in 80 MB increments. If you run many applications, and you do not have enough RAM, a large swap partition will be evaluated. After you have made your choice, you must format the hard drive. Caution, this operation erases all data from your hard drive. Therefore, you must perform a backup of your disk in advance. In this regard, there is a tutorial for breaking the disk, which you will find. Now that your computer is up and running again, it's time to change your system to devote your new virtual memory partition. The line that interests us here is the fifth one. |
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Marking |
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Spindle rotation speed, rpm |
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The recording density, GB per plate |
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Volume of cache buffer, MB Then enter the command in the terminal. Type the following command at the beginning of the line. To do this, always enter a command in the terminal. The file opens, but the file is very large, you need to perform a search to get to the place that interests us. Inserting the # character at the beginning of the line cancels the reading of this line by the system. Thus, you simply cancel the old position of your virtual memory. Now it should provide a new place for your virtual memory. To do this, go to the end of this line with the right arrow on the keyboard and press the enter key. |
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Bearings |
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Interface |
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NCQ Support |
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Range of capacities |
120, 160, 200, 250 |
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Inside. speed of data exchange, Mbit / s Then you return to the line. Then, re-enter to confirm your line. You should get this at the end of this operation. To activate the Swap partition, restart the computer. There are two ways to test your work. For terminal enthusiasts, enter the command. You should get this in return. Make the swap partition invisible. For reasons of comfort, it may be interesting to make your swap partition invisible. Please note that you must register to access the downloads. Open the terminal and enter the following command. |
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Average access speed: average, ms |
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- according to the maximum radius, ms |
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- transition between tracks, ms |
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- write access speed, ms The terminal will ask you for a password. To check if your changes were accepted, enter the following command in the terminal. Therefore, the parameter change was well written down. So you just need to restart now. But it is often enough to set it up correctly so that it becomes problem-free, even on machines that are less fast. Settings do not take a lot of time and can make a huge difference! This is a simple and effective way to see the file's footprint on your system. By clicking on the symbol to the right of it, you can change the indicator to show you other information, including "efficiency." Attention: after cleaning it is impossible to return. This saves energy when multitasking, allocating weaker resources for background applications. It is very easy to disable this feature. |
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Impact resistance (offline), G |
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Impact resistance (online), G |
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Sound level when idle, dB |
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Noise level at positioning, dB What are the cache levels or the size of the mosaic?From my point of view, miniatures are not very useful, turning them off allows you to get even more performance. To disable them, click the button "Bud" in the upper right corner of the layers palette, select "Panel Options", and then "Sketch Size" select "No". If you work with large files with very few layers, you can consider. However, the current operations will be slower. It all depends on how you use the software. Top and tone: this is the setting that you should use if you are working with small files and many layers. Large and flat: if you are a photographer, this is the setting that will be used for you. It will set the cache levels to 2 and the size of your mosaic to 128,000. The meaning of your story is the maximum number of spins you can make. |
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Testing
The testing involved hard drives from three manufacturers - WD, Seagate and Samsung. At the time of writing, it was their products that were represented in a wide range. The copy of the Caviar SE16 series hard disk considered in the review had the following parameters:
- marking WD2500KS-00MJB0;
- the volume is 250 GB;
- microcode version 02.01C03;
- the "silent positioning" (AAM) mode is disabled (0FEh).
We will compare with it the following hard drives:
- Caviar SE, from the line with 8 MB buffer, 200 GB:
- marking: WD2000JS-00MHB0;
- the buffer size is 8 MB;
- interface - Serial ATA 3 Gbit / s, NCQ is not supported;
- the microcode version is 02.01C03 (the same one);
- the silent positioning (AAM) mode is disabled (0FEh).
- Samsung SpinPoint P120, 200 GB:
- marking SP2004C;
- the buffer size is 8 MB;
- interface - Serial ATA 3 Gbit / s, NCQ supported;
- microcode version - VM100-33;
- the "silent" positioning mode is enabled (code 00h).
- Seagate Barracuda 7200.8, 200 GB:
- marking ST3200826AS;
- the buffer size is 8 MB;
- interface - Serial ATA 1.5 Gbit / s, NCQ is supported;
- microcode version - 3.03;
- the "silent" positioning mode is locked (control is not available).
Hard drives Seagate and Samsung have a higher recording density than WD Caviar. In addition, Seagate has a higher claimed positioning speed (8 ms versus 8.9 ms for Samsung and WD), and Samsung is running quieter. That is, WD does not formally have advantages over other manufacturers' drives. But in practice, it can be the opposite.
The hard drives were connected to the second port of the Serial ATA controller built into the southern ICH5 hub of the Intel 865G chipset. Unfortunately, the 865 chipset does not support 3 Gbit / s and NCQ technology, so the capabilities of modern hard disks can not be fully revealed. Other parameters of the test configuration:
- the host hard drive from which the OS was booted and the tests started - Seagate Barracuda 7200.7 PATA 80 GB;
- processor Intel Pentium 4 2.80 (800 MHz bus);
- motherboard Intel D865GBF (Intel 865G);
- memory 2 x 256 DDR400, two-channel mode is enabled;
- geForce FX 5600 graphics card;
- winchesters were installed in a 2.5-inch basket of the Inwin J551 case, special cooling was not used.
Low-level tests
Using programs that work with the disk directly, allows you to measure the theoretical parameters of the hard drive - the speed of random access, the averaged (sustained) speed of reading and writing, the effectiveness of deferred recording. In this case, the effect of caching algorithms is minimal, since access is continuous and according to a simple scheme.
Low-level parameters were calculated with the help of programs:
- IOMeter 2004.07.30;
- HDTach 2.68;
- HDTach 3.0.1.0;
- Winbench 2.0 (the disk was formatted for one large NTFS partition).
Access speed was higher in Caviar, because WD hard drives do not use position-moderation algorithms (AAM). Seagate, despite the excellent numbers claimed, was the last. Strangely enough, Caviar SE16 has lost a little (0.3 ms) to its fellow, which can be explained either by the natural spread of technological parameters (still the mechanics has some deviations in one direction or the other), or by the influence of the third plate (the larger the number of heads, the more delay in their switching). Of course, the differences are actually very small, and we will not talk about the serious lag of the Caviar SE16. On the speed of access when writing WD hard drives are equal, providing a double acceleration compared to the speed of access when reading. This is explained by the influence of the delayed write algorithm.
By sequential read / write speeds Caviar SE16, by contrast, slightly outperformed Caviar SE. But they were overtaken by the Seagate hard drive (+ 10%), which is natural due to the use of a higher recording density, and Samsung, on the contrary, is just as behind.
A more accurate analysis of the read / write speed allows you to conduct an IOMeter. If other programs work with 64 KB blocks, the IOMeter can vary the block size.
Seagate is in the lead in reading: it significantly better (+ 20%) copes with small and large blocks. Samsung, as it turned out, works very poorly with small blocks. And WD performed well in the write tests, bypassing Seagate when working with blocks less than 64 KB.
The program Winbench'99, despite its venerable age, rather accurately builds a schedule for sequential reading.
Both WD discs have the same shape of the graph, with no peaks and dips, which indicates a high stability of reading. The graph of the Caviar SE16 is more elongated, due to its greater capacity. An increase in the scale of the chart allows us to consider short-term, but strong speed dips in Seagate and Samsung (the work of ECC error correction algorithms, delay in switching heads and changing tracks) and the absence of those in WD. And let the recording density of WD is worse, the proven production technology has its advantages - higher stability of work.
Simulate application performance
The Workstation template of the IOMeter test allows you to generate a load on a disk subsystem close to the real one (statistics were collected using the Winstone 2002 Content Creation test). So, this test is more sensitive to the access speed than to the read / write speed, plus it takes into account the work of caching algorithms, because queries come with an increase in the depth of the queue.
According to the data received, both WD drives slightly outstripped Samsung and literally smashed Seagate. Caviar SE again is slightly better than Caviar SE16, as they have a small difference in access speed.
On the PCMark05 test, we had great hope, since it is he who should show the advantage of a large cache buffer. This test uses templates written using the Intel IPEAK SPT test suite when performing certain tasks. Therefore, PCMark05 can more or less believably simulate the hard drive in real conditions.
So, if the speed of Windows XP boot, copying files and scanning for viruses WD hard drives are almost the same, then by the speed of loading applications and accessing data while running applications Caviar SE16 is 10-15% faster than Caviar SE, not to mention Samsung and Seagate.
The advantage of a hard drive with a large buffer is also noticeable in the Winstone test, especially if the FAT32 file system is used.
conclusions
The results of testing prove: there is a positive effect from the increase in the buffer. It is small, within the limits of 10-15%, and it is shown only when the hard drive is operating under conditions close to real. In low-level tests, there is practically no difference, which is consistent with the theory. The same theory says that with increasing interface bandwidth and recording density, as well as with the introduction of technologies to optimize access to the disk, the buffer size will have to be increased. Therefore, the developers of WD a little hurried; however, it is better to start working out the technology now than to catch up with competitors afterwards.
Rating 4.9 out of 5. Votes: 379. Category Choose a computer technique
A hard disk (hard drive, HDD) is one of the very important parts of the computer. After all, with a breakdown of the processor, video card, etc. You feel sorry only for losing money for a new purchase, with a hard drive crash, you risk losing without losing important data. Also, the speed of the computer as a whole depends on the hard drive. We'll figure it out, how to choose the right hard disk.
Hard Drive Tasks
A task hard drive inside the computer - save and give out information very quickly. The hard drive is an amazing invention of the computer industry. Using the laws of physics, this small device stores almost unlimited amount of information.
Hard Drive Type
IDE - obsolete hard drives are for connecting to old motherboards.
SATA - replaced hard disks IDE, have a higher data transfer rate.
SATA interfaces come in different models, they differ in the same speed of data exchange and support for different technologies:
- SATA-has a transmission speed of up to 150mb / s.
- SATA II- has a transfer rate of up to 300mb / s
- SATA III- has a transmission speed of up to 600mb / s
SATA-3 began to be released not long ago, from the beginning of 2010. When you buy this hard drive, you should pay attention to the year of your computer (without upgrade), if it is below this date, then this hard drive will not work for you! HDD - SATA, SATA 2 have the same connectors and are compatible with each other.
Hard Drive Capacity
The most common hard disks that most users use at home have a volume of 250, 320, 500 gigabytes. There are even fewer, but there are less and less 120, 80 gigabytes, and on sale they are not at all. For the possibility of storing very large information there are hard disks of 1, 2, 4 terabytes.
Speed and cache memory hard drive
When choosing a hard disk, it is important to pay attention to its speed (the speed of the spindle). This will determine the speed of the entire computer. The usual speed of the discs is 5400 and 7200 rpm.
The amount of buffer memory (cache memory) is the physical memory of the hard disk. There are several sizes of such memory 8, 16, 32, 64 megabytes. The higher the RAM speed hard drive, the faster the data rate will be.
In custody
Before buying, specify which one is suitable for your motherboard: IDE, SATA or SATA 3. We look at the characteristics of the rotation speed of the disks and the amount of buffer memory, these are the main indicators that you need to pay attention to. We also look at the manufacturer and the volume that will suit you.
We wish you successful purchases!
Share your comments in the comments, this will help other users to make the right choice!
