(A) The advantages of SSD:
First, the SSD does not require mechanical structure, completely semiconductor, there is no data lookup time, latency time and disk seek time, data access speed, the ability to read the data in the more than 400M/s, the highest currently up to 500M/s or more.
Secondly, SSDs all use flash memory chips, which are durable, shockproof, and resistant to drops, so even if there is a collision with a hard object, the likelihood of data loss can be minimized.
Third, thanks to the absence of mechanical parts and flash memory chips, SSDs have no noise and low power consumption.
Fourth, it is lightweight, weighing 20-30 grams less than a regular 1.8-inch hard drive, making it possible to carry multiple SSDs in a portable device. At the same time, because it is fully semiconducting and has no structural limitations, it can be designed as a special electronic hard drive with a variety of different interfaces and shapes according to the actual situation.
(2) Disadvantages of SSDs:
First, the cost of SSDs is high The cost of SSDs has fallen dramatically. 128G SSDs are now at the $1000 level. But relative to the mechanical hard disk, the price is still very high ~ and as a notebook manufacturer, in the SSD as an optional accessory, the cost of upgrading is much higher than the actual cost, which also leads to a traditional hard disk notebook equipped with a solid state drive notebook between the thousands of dollars of the price difference.
Second, the storage capacity to be improved Today's traditional mechanical hard disk with the latest perpendicular recording technology has been to 2TB level, while the highest record of SSDs still stays at a few hundred gigabytes (PQI launched 2.5-inch SSD products) or so, due to the cost of flash memory has been high, very few vendors involved in the research and development of this high-capacity SSD products, even if there are related products The most practical storage capacity of SSDs you can buy at this stage is only up to a few hundred gigabytes (GB), but the price is high.
Solid state drive life cycle calculation formula
The second part of the process is to clear the misconceptions!
1. Why isn't SSD speed always at its highest speed?
A: Most SSD manufacturers now claim that their SSDs have sustained read and write speeds of more than 500MB/s, which is quite impressive compared to the 100MB/s speed of mechanical hard drives. In fact, almost no program startup and execution process is continuous reading, the actual use of only non-disk copy and paste operations, the source of the data disk will continue to read the work. In other words, when you copy and paste a file from the D drive to the E drive, the D drive is continuously being read and written to.
2. If my hard drive reads and writes a lot, won't the SSD last long enough to be obsolete?
A: On some SSDs, you will see that the chip is labeled for only 10-1 million read/write cycles. So if I apply to databases and the like, perhaps read and write more frequent data, not quickly broken, then we buy a solid state drive is not very cost-effective"? The lifespan is certainly not as long as that, and if it's not safe, it won't be used in aerospace, automotive, and other specialties and harsh environments!
Solid state drives are basically constructed on the principle that there is a lot of similarity to the way we apply ordinary mechanical hard drives, such as analog sectors, analog tracks, and so on. Inside the SSD, the core part is the controller, which is the heart of the entire SSD, including many architectures, such as read/write algorithms, interface definitions, etc. The main impact on the lifespan is the number of read/write cycles. The main thing that affects the lifespan is the number of read/write cycles, and in the definition of the SSD algorithm, a modification of the algorithm counts as a real read/write cycle.
Solid state drive flash memory has a limited number of erasure times, which is where many people criticize its short lifespan. A full flash memory erase is called a P/E, so the lifetime of a flash memory is measured in P/E. A 34nm flash chip has a lifetime of about 5000 P/E, while a 25nm chip has a lifetime of about 3000 P/E. Doesn't that seem shorter? Theoretically, yes, but as SSD firmware algorithms improve, newer SSDs are delivering fewer unnecessary writes. A specific example, a 120G SSD, to write 120G files to do a P / E. Normal users qua normal use, even if the daily write 50G, an average of 2 days to complete a P / E, then there are 180 times a year P / E. You can calculate their own 3,000 P / E can be used for a few years, I believe that by that time, the SSD has long been replaced by you what else? The first thing you need to do is to get a new, more efficient, and more reliable SSD.
Currently, BladeCenter HS21 XM blade servers offer solid state drives (SSDs) based on flash memory technology, which are faster, more reliable, more energy efficient, less hot, and quieter than traditional mechanical hard drives, and can run operating systems and any other applications on the blade server. They can run the operating system as well as any other application, and also show that longevity is no longer a concern.
With the Flash chip erase the number of times continue to improve, life is also constantly improving, according to some current applications, the general life of a disk can reach more than 6 years, and the controller's algorithms continue to improve, life is also disguised as another aspect of the increase in life, I believe that the future life of the great improvement. The first step in the process is to optimize the SSD for the next generation. The best firmware contains advanced algorithms that reduce the amount of unnecessary writings on the SSD, thereby reducing the wear and tear on the flash memory chip, maintaining performance, and extending the life of the SSD. It is important to keep up to date with the latest official firmware releases.
Optimizing SSDs
There are two general approaches to updating SSD firmware: a software update on Windows, and an update on a bootable drive (USB flash drive, CD-ROM). The update process is roughly a simple matter of changing the boot sequence of the motherboard's BIOS to optical drive priority or USB flash drive priority, then entering the boot screen and following the prompts.
2. Turn on the TRIM command
SSDs get slower the more you use them, which has a lot to do with how they work. SSDs are new, and the NAND flash memory in them is pre-erased, so data can be written directly to the flash memory without having to complete the data erasure step, which is very fast. As time goes on, there is less and less storage in the SSD that is never used, and in many cases the data in the flash must be erased before it can be written, so its performance drops significantly.
On Windows 7, launching the Trim command on SSDs that support it enables the operating system to tell the SSD master that this block of data is no longer needed after a file is deleted or formatted. When a file is deleted or an entire partition is formatted, the operating system sends the Trim command to the SSD master along with the Logincal Block Address that was updated during the operation (which contains the invalid data address), so that the invalid data can be cleared out during subsequent Garbage collection operations.
With the SSDs, you can also use the SSDs in a variety of ways, such as by using the SSDs as a storage device, or by using the SSDs as a storage device.
Windows 7 has the Trim command turned on by default, so if you want to check the status of the Trim command, you can enter the command prompt with administrator privileges and type "fsutil behavior QUERY DisableDeleteNotify "and we will get a feedback about the status of the query. Here, the prompt is "DisableDeleteNotify = 0" that is, the Trim command is enabled; the prompt is "DisableDeleteNotify = 1" that is, the Trim command is not enabled. In addition to open the motherboard BIOS AHCI mode is also very important. The Native Command Queuing feature (NCQ) of AHCI optimizes the order in which users send their commands, thereby reducing mechanical load and improving performance.
Check out the Device Manager - IDE ATA ATAPI Controller, if AHCI is enabled, there will be a prompt behind the controller, if not, it's not enabled.
3. Secure Erase
The ATA Secure Erase command can be used to erase all user data on the disk, which will return the SSD to factory performance (optimal performance, minimal write amplification). But the effect is only temporary, because after the use, write amplification will slowly increase back again, and finally will return to the stable state. However, when an SSD is used for a while and the files in it are cluttered and the performance decreases, it's still necessary to do a secure erase (and reinstall the system anyway).
Now there are many software can provide ATA security erase command to reset the disk WwW.PC841.CoM, the most famous is HDDErase. However, for SSD, reset once is also equivalent to complete a P/E, so here is not recommended to do erase optimization frequently. The process is also roughly the same as changing the boot sequence of the motherboard BIOS to optical drive priority or USB flash drive priority, and then inserting the boot device with the stored software, entering the boot interface, and following the prompts to operate.
In addition, Intel SSD Toolbox is Intel's official management tool for Intel SSDs, which also includes optimization features, and is similar in principle to the software, but is easier to use because it is software.
Four, SSD purchase
1, look at the main control chip
Currently on the market with the highest share of SandForce II main control, because it provides a set of mature main control program. Hard drive manufacturers only need to buy the program, in addition to adding their own PCB design, flash memory with, firmware algorithms can be manufactured solid state hard disk. Somewhat similar to Google's Android open source model, but its disadvantages are the same, that is, the same master control to be compatible with a variety of different chips, firmware, so the major SandForce master control of the hard disk product performance is also uneven. In addition, there are also Marvell and Intel controllers, which have fewer products, but their performance is quite impressive.
2, look at the flash particles
The flash particles used in the former SSD have a 25/34nm process, MLC/SLC, synchronous / asynchronous, ONFI / Toggle Mode and so on. ONFI particles are only 50MT/s (Intel or Micron early particles), synchronous ONFI 2.x particles can reach 133MT/s ~ 200MT/s (Intel or Micron particles), asynchronous Toggly DDR 1.0 particles can also reach 133MT/s ~ 200MT/s (TOSHIBA or Samsung particles). The newest addition to the DDR3 memory is a new DDR3 memory card that can be used in a wide variety of applications.)
Liquid crystal display backlight type and advantages and disadvantages (LCD, CCFL, LED) (I)
Liquid crystal backlight display principle Liquid crystal is different from plasma the biggest difference is that the liquid crystal must rely on a passive light source, while plasma TV belongs to the active light-emitting display device. The mainstream LCD backlighting technologies currently on the market include LED (Light Emitting Diode) and CCFL (Cold Cathode Fluorescent
lamps).
Cold Cathode Fluorescent Lamp (CCFL)
Traditionally, LCD monitors have been backlit with CCFL (Cold Cathode Fluorescent Lamp) backlighting, and there are two main types of CCFL backlighting designs: "Side Entry" and "Direct Entry". "and" straight down "but the side into the type because of the light guide design makes the light refraction rate is high, and then let the backlight brightness is limited, the larger the size of the panel, the lower the brightness, only suitable for 8 inches to 15 inches of TFTLCD panels, that is, the Laptop, Desktop and other personal viewing The LCD TVs in the home viewing area are large enough that the side-by-side brightness will be difficult to meet, instead of the direct-fall type.
However, the larger the size of the LCD, its backlight module accounted for the higher proportion of the cost, referring to the direct-fall CCFL backlight module, according to statistics, the same is the use of direct-fall CCFL backlight module, in 15 inches when the backlight module only accounted for the overall cost of 23%, but to 30 inches when the cost increased to 37%, and estimated to 57 inches, the cost of backlight module will reach 50%. will reach 50%. Therefore, direct-fall CCFL backlighting is only suitable for use in about 30 inches of medium-sized LCDTV, is not suitable for use in a larger area of the design. At the same time, CCFL is the use of mercury gas discharge to produce lighting, although the EU RoHS specification, as long as the "mercury" dose below the standard is still acceptable, but no one can guarantee that in the future the standard may be raised to zero content (not allowed to use completely), when the CCFL will not be able to use, or must be changed to non-mercury type CCFL.
Even if a mercury-free CCFL is technically feasible, a CCFL is still a gas-discharge type of electronic lighting with a closed tube, and the tube's resistance to external forces is limited, so a larger impact will cause the tube to rupture, rendering the lighting ineffective, and the other solid-state electronic lighting (e.g., LEDs) will not have this concern. In addition, due to the straight down type do not need to use the light guide, but also more no light refraction problem, so do not need to brighten the film, especially brighten the film is a small number of operators of the patented technology, expensive, straight down type can be eliminated with the guide and brighten the film, which will help reduce the cost.
However, direct-fall CCFLs also have their drawbacks, in order to increase the brightness of the screen, you must increase the number of light pipes, but the light pipes are too densely arranged results will not be conducive to heat dissipation, since the distance between the left and right phase space to shrink, so we have to increase the thickness of the level of space to increase the heat dissipation, however, the thickness of the increase is equal to the partial loss of the advantages of the LCD TV: thin and light.
Incidentally, the use of CCFL light pipes on large-inch LCD TVs, the length of the light pipe must also be increased in response to the increase in the number of inches and growth, but the longer the CCFL light pipe, the middle of the light pipe and the two ends of the light pipe will be easy to produce brightness MURA and color MURA problem, which affects the backlight of the light uniformity in order to continue to maintain the light uniformity, it is necessary to use a diffusion film to enhance the light uniformity, but the diffusion film will also bring about light uniformity. But the diffusion film will also bring the loss of light transmittance, so that the brightness is reduced, the result of the reduction in brightness had to increase the number of light pipes to make up for the way, but as mentioned earlier: increase the light pipe will be more difficult to design the heat dissipation, increase the thickness of the backlighting module, and even an increase in power, according to the understanding of CCFL backlighting module has accounted for the overall power consumption of the LCDTV power of 90% of the high. Therefore, changing the backlighting technology is currently one of the directions to change the LCD picture quality.
Light Emitting Diode (Light Emitting Diode; LED)
Since CCFL backlighting has a lot of side effects of doubt, so the industry is also looking for a variety of new backlighting to achieve the technology, and the LED is one of the feasible options, such as Sony's Qualia series of TVs, that is, the high-end Large size (40 inches, 46 inches) LCD TV, the backlight part is composed of WLED, called WLED backlight technology. And the LED backlight technology LCD Monitor R & D has been to the substantive stage, we have been in the 07 CES exhibition can be seen on the relevant product display.
LED backlighting has a number of benefits, first of all, solid-state electronic lighting, on the impact of the ` resistance to higher than CCFL, and there is no mercury gas environmental regulations concerns, no UV UV leakage concerns, while the color saturation and longevity are beyond CCFL, in addition to the LED
As long as the positive voltage can be driven, unlike the positive and negative voltages of the CCFL needs to be exchanged, even if only the positive drive voltage, the LED backlighting technology is a good choice. Even if it is only about the positive driving voltage, LED's demand level is lower than CCFL. furthermore, the brightness of the LED only need to use the pulse width modulation (Pulse Width Modulation; PWM) can be adjusted, and can be used in the same way to inhibit the problem of residual shadow on the display of TFTLCDs, however, the brightness of the CCFL is more complicated to regulate and can not be inhibited residual shadow, must be a separate way to inhibit. The CCFL brightness adjustment is more complex and does not suppress ghosting, which must be suppressed in a different way.
Although the LED backlight has many advantages, but also has its shortcomings, the first is the luminous efficiency, in terms of the same electricity, LED and less than CCFL, so the heat dissipation problem will be more serious than CCFL, in addition to the LED is a point source of light, and the CCFL line light source is more difficult to control the light uniformity, in order to achieve the best possible light uniformity, it is necessary to produce out of the LED characteristics of the Pick and choose, will be a large number of characteristics of the same (wavelength, brightness) LED used in the same backlight, the cost of this selection is also quite high. Fortunately, the luminous efficiency of LEDs is still improving, and is now available to more than 100ml/W, so that color saturation can be better, as well as allowing the backlight of the WLED row more relaxed, and then let the power and heat problems to get relief, and manufacturing yields continue to progress after the maturity of the LEDs to select the same characteristics of the brightness of the cost of the LEDs will also be reduced.
Changing the backlight technology alone may not be enough to trigger a revolution in LCD, then we will look at other LCD technology development. OLED (Organic Light EmittingDiode) that is, Organic Light Emitting Diode (OLED) display technology is different from the traditional way of displaying the LCD, no backlight, using a very thin coating of organic materials and glass substrate, when there is an electric current through the glass substrate, it is possible to use the OLED to display the LCD in a different way. Glass substrate, when there is current through, these organic materials will emit light. Moreover, OLED display screens can be made lighter and thinner, with larger viewing angles, and can save significant power. However, its lifespan and price are currently the bottlenecks limiting its development in LCD.
OLED is another panel application technology that is receiving attention, and the realization of small-sized panels is on an early schedule. In terms of customer's plan, there will be more models coming out in 2008~2009, but still dominated by sub-panels, and even if the models and shipments have increased significantly compared to now, the market share will not be more than 10 percent. -LCD, a few years ago, have also invested in research and development. However, on the one hand, OLED technology itself has encountered a bottleneck, life expectancy issues to be overcome; on the other hand, TFT-LCD technology continues to improve, and now also able to provide excellent contrast and viewing angle, resulting in the demand for OLED has never been able to greatly enhance the market is not too large and oversupply, limited to the price of the competition; the original investment in the industry is also difficult to escape the fate of the dissolution and downsizing. Taiwan Shenghua technology in the past to invest in the establishment of Shengyuan into OLED research and development, see OLED and TFT-LCD can not compete, especially the cost difference is large, the specifications of TFT-LCD can easily reach 170 degrees of viewing angle, 500:1 contrast, brightness increase, can also be made thin, the response speed, although inferior, but to the extent that the human eye can be accepted. Therefore, ShengYuan has also been closed, leaving only a few R&D personnel to return to ShengHua to do the development of materials. In the future, if the life and price of OLEDs can be significantly improved, there will still be opportunities; at this stage, it is limited to products with special features that emphasize the need to be new and different; the point in time when the volume is large is yet to be seen.
AMOLED (Active Matrix/Organic Light EmittingDiode) active matrix organic light-emitting diode panel (AMOLED) is known as the next generation of display technology, including Samsung Electronics, Samsung SDI, LG Philips are very important to this new display technology. At present, in addition to Samsung Electronics and LG Philips to develop large-size AMOLED products as the main direction, Samsung SDI, AUO, etc. are small and medium-sized for the development direction. From the current finished product product performance, if AMOLED cost can be effectively controlled, then, the traditional LCD panel technology will be greatly challenged.