Speed is the pursuit of every geek, in order to improve the charging speed, I studied all kinds of charging head, wrote a "quick charge on PD and fast charge charger selection guide to see which one is enough", was also Zhang aunt Home recommended. Today we'll chat with the theoretical speed limit mechanical hard disk / solid state disk / U disk / NAS and other equipment is much to see in the end the read and write speed is limited in what areas, and how to enhance the daily use of hard disk read and write speeds, let your hard disk to play to the desired performance.
First, the basics of speed
Turning speed must first be clear under the concept of "speed unit" in:
Bit (bit, b) is the smallest unit of information, the information is a binary number comprising only two states: 0 and 1. For example: a computer word length is 16 bits, i.e. 16 bits, then the value is the information it represents 0-65535.
Byte (Byte, B) is a unit of measurement techniques for computer information storage capacity measurement, a string of binary digits handled as a unit, is a small unit configuration information. The most commonly used is eight bytes in byte, i.e., eight of which contains a binary number. Byte = 'bit. 8. 1 .
The difference between B and iB : 1KB (Kilobyte) = 1000Byte, 1KiB (Kibibyte) = 1024byte. Drive manufacturers are GB (decimal, i.e. the third power of 10, such as 1GB = 1000MB, 1MB = 1000KB) calculation, and the computer (the operating system) is GiB (2 binary, i.e. 10 th power of 2, such as 1MiB = 1024KiB) calculated. But domestic users is generally understood to 1MiB = 1M = 1024KB, so in order to facilitate understanding of the culture, translation MiB for the MB is also possible. Also according to the hard drive manufacturers and users for different interpretations 1MB in size, according to the actual capacity of the hard disk of the computer actual 1MiB = 1024KB operator not to nominal capacity, which may explain why buy a new hard drive "not honest" and it did not marked so much. For example, I bought two sizes respectively 2T and 500G hard drive shows the actual capacity is only 465GB and 1863GB on the computer.
The bandwidth (bps) refers to the amount of data per unit of time by the link. Typically bps (bit per second) to indicate that the transmission of bits per second can. We call the network speed, the transmission speed is the bytes transmitted per second (MB / s, KB / s ). Common Gigabit Router, Fast broadband networks are referring Mbps, to be converted into speed, then had divided by 8. For example a bandwidth 100M = 12.5MB / s network speed, the maximum transmission speed of Gigabit Network Theory 125MB / s (1Gbps = 1Gbit / second = 125 MB / s). So do not complain about your home dozens of megabytes of broadband telecommunications ye not tens of megabytes of download speed friends ~
Second, how fast the hard drive
1, the principles and theoretical speed hard disk
Mechanical hard disk (HDD) mainly by: some part of the disk, the head, and the disk spindle motor control, the head controller, data converters, interfaces, buffers and other components. Moving the magnetic head along a radial direction of the disk, the disk plus several thousand revolutions per minute high-speed rotation, the head can be positioned at a predetermined position on the disk to read and write data. Information from the close to the surface of the magnetic head to change the flow by an electromagnetic flow electromagnetically polarities written to disk, the information can be read by a reverse manner.
Solid state drive (SSD) hard solid state electronic storage chip is made of an array with fast read and write, light weight, low power consumption and small volume, but once hardware damage, data recovery more difficult, a flash memory having a rewritable Q limit the number of durability (life) is relatively short.
Hard disk usually through SATA interface to connect to the motherboard, although the theoretical speed SATA3 interface is 6Gbps, but the mechanical hard disk can not run a full touch even say that 50% of all luxury. Further mechanical hard disk transfer speed with the transmission of the file size of a relationship, the smaller the file, then the slower speed of the debris. The average current conventional hard disk transfer rate 250MB / s (source). Argument is also a kind of write in the average speed of about 60 ~ 170MB / s between the (source). The use of SATA interface SSD speed 500MB / s or so, NVMe solid reach 3000MB / S .
(Source [whistling] understand science solid state drive SSD, could be so simple!)
2, the mechanical hard disk cache
Write cache provides mechanical hard disk speed data buffering, the first read buffer is either write data or read data to the hard disk and then supplied to the computer, so as to ensure stability and higher data transmission speed. A larger cache can significantly improve the capacity of the burst disk read and write speed of the machine, especially when the mechanical hard disk frequently modified data, to maximize its performance, and can significantly improve the mechanical lifetime of the hard disk.
Due to the cache, when transferring large files start fast, then slow down the speed, the two concepts involved here: the hard disk of the average transfer rate and burst transfer rates .
Burst transmission rate is received at the moment the hard disk of the read and write commands, read data from the hard disk cache speed, since the cache is a semiconductor, which is much greater than the actual write speed and write speed hard disk, even up to GB / s level.
Average transmission rate is determined mainly by the rotation speed and head seek time of the hard disk, this speed is late at a steady rate, a disk drive to read and write commands, the drive head seek, read and write data, then the data rate sent via the external interface, is the actual hard work can achieve sustained rate. That is, the above mentioned 60-250MB / s.
3, SMR technology and mechanical hard disk PMR
We usually buy hard to focus only on the brand, capacity, speed and other parameters, in addition to the fact that there are several key manufacturers never standard, ordinary consumers have no way of knowing, but it is a very important parameter - a hard disk drive (HDD ) magnetic recording technology. There are mainly two: perpendicular magnetic recording (PMR) and shingled magnetic recording (SMR). You can see the difference between the specific principles and B station bonjour whirring video, and know almost Q Why mechanical hard drive currently on the market is not big mark whether SMR technology?
It simply is SMR technology while improving the single platter and reduce the number of discs, but also reduces the price . But SMR hard disk when rewriting data will overwrite data in adjacent tracks, to put the data into the buffer store nearby, then writing new data, old data and then write back, leading off speed, heat, noise and other issues . SMR technology using a hard disk may be a hard disk and a non SMR is no different in just bought the "blank" state; but in use for some time, disk space is gradually filled with the data, problems will begin to expose the SMR, which is read take the data is no problem, but the write (rewrite) data will be particularly slow, the SMR full hard disk capacity, the slower write .
Generally, cache 64MB are perpendicular technology (PMR), 256MB are shingled. Buy mechanical hard drive, then try to bypass the SMR hard Guidance can refer to the white buy mechanical hard to avoid the pit and Selection Guide. You can also view the Excel spreadsheet link, which has detailed parameters Seagate / Western Digital / Toshiba two hundred variety of mechanical hard drives, allowing you to identify one of your hard drive is not the SMR. Now fewer and fewer non-SMR hard drive, even if your hard drive is not too worried SMR, since SMR as a new technology and a large-scale commercial, everyday use is no problem, after all, has a two-year warranty hard drive , free ones do, but the official warranty and does not include data recovery , usually still have to do data backup , hard disk, but you know the entire mainframe computer hardware inside the easiest failure.
4, a hard disk read and write speed test
Once you understand the theoretical speed limit of HDD and SSD, at the next test in my hand a few mechanical hard drives and solid state drives to see how the actual transmission performance. I bought a few pieces of hard disk earlier than before to buy time do not know, looked at now, NAS, and mechanical computer inside a few Seagate hard drives are not imbricated, do not worry about the capacity is almost full speed out of the question. But that several have been discontinued, and now 2T Seagate hard drives are mechanical models of the shingled. SSDs hostel with Toshiba Q300, a TLC particles 240GB solid state drive. With the Department before Samsung 850 EVO, only 120GB, then filled with a change of 860 EVO 500GB of. Do not ask me why not buy a better MLC particles, student party Qionga.
Hard disk speed test when you want to copy between two hard drives are the average transfer rate , if you copy the file is in a different hard disk partition, and finally the slower than average transfer rate, because the hard drive to read and write at the same time. Here is the interface description of CrystalDiskMark test software.
CrystalDiskMark speed results are shown below:
Test results show that the overall performance of Seagate's new 2TB mechanical hard drive is better than the older 500GB and 1TB hard drive, but the difference is not too great. Leading all-round performance SSDs mechanical hard drive, solid state hard drive performance large-capacity significantly smaller than the capacity to be better (specific reasons can be seen whirring science video mentioned above). SSD sequential read test (seq) is not very different speed, write speed is 2-3 times that of the HDD. 4K random read and write speeds with mechanical hard drive is not an order of magnitude, this is really stronger than SSDs mechanical hard place, like a kind of small DLL file, the software running it will be called frequently, especially at boot time . The advantage is fast SSD read and write these small files, so that the disk performance, does not appear Caton.
Running sub-results can only be a reference, let's look at the actual copy large movie files in speed between how hard:
SSD can be seen from or written to the HDD with HDD writes between the disk can reach 200MB / s, this should be the upper limit of the mechanical hard disk write speed. Transmitted between the HDD affected simultaneously on different disk read and write operations, the speed falls below 50MB / s, Seagate 1T can be seen clearly in FIG disk speed triangular profile, which is due to the different areas of the hard disk read-write (or near the center away), or disk bad sectors caused.
SSD from HDD write, read performance is affected HDD, two Samsung SSD write speed of only 150MB / s, write speed between SSDs reached 250MB / s, Toshiba SSD performance eye-popping, the same TLC is SSD performance than Samsung is a big change it!
5, USB2.0 VS USB3.0 U disk read and write speed test
Hard over speed test, some hand USB2.0 (black core), USB3.0 (blue core) of the U and removable hard disk device, but also to test the read and write speed thereof.
You can see the speed of USB2.0 and USB3.0 big change, you can basically say goodbye and equipment of the USB2.0. Is also a U disk and removable hard disk read speed of USB3.0 is not very different, but the write speed is a difference of ten times. That is, against the others to share your download little sister, then take the mobile hard disk U disk copy than ten times faster time.
6, hard disk summary
Current methods to enhance the mechanical hard drive speed is mainly to increase caching and enhance speed . Theoretically cache is the bigger the better, but a problem that must be considered is cost-effective, large buffer is costly, but the performance gains often do not imagine the big, now mostly PMR hard disk 64MB cache , SMR due to the writing characteristics are generally 256MB.
As for speed if not better , higher speed means more power consumption and noise, but also more prone to damage in the collision and movement, and now the mainstream 2.5-inch notebook hard drive is 5400 RPM, 3.5-inch desktop the hard disk is 7200. 15,000 rev / min are used in the majority of the hard disk on top of the server, the server once the shelves are almost not move, and have done most of the hard disk server raid, and therefore not afraid of a bad hard drive, so will the pursuit of read and write speed, ignore the risk of damage to the hard disk, regardless of high power consumption and more big noise problem.
Seagate has also announced the introduction of multi-drive motor technology, making double the performance of the HDD. Dual-motor means that you can transfer / retrieval double the data read and write performance is doubled. However, the resulting cost and weight problems, the technology has not been available products.
As battery technology as the mechanical hard drive performance put the Buddha encountered a bottleneck stagnant, 7200 rev / min and 64MB of almost ten years with nothing changes. 5G coming era, is bound to put forward higher requirements for read and write speeds, then we must look SSDs, as to be SLC, MLC or TLC is a deep topic.
To sum up, the money on SSDs, especially the system disk, SSD will bring the overall performance quality improvement. The higher cost of installed capacity mechanical hard drive is still necessary, try to choose a non-mechanical hard disk shingling technology, U disk buy at least USB3.0, while supporting the USB-HUB should be USB3.0. This is the moment to play hard optimum performance it!
Three, NAS How fast
NAS (Network Attached Storage: Network-attached storage) is a private cloud , but also a cloud storage. In simple terms is to plug the Internet cable to your hard disk, the hard disk contents connect to the Internet, you can access anywhere else. Public cloud data storage Baidu network disk like on Baidu's servers , and NAS data stored in your local hard drive. NAS specific introduction written before in my public in a number of Amway NAS know, are interested can look at. NAS enables remote access, file sharing, data backup, set up server functions, etc., in short, is very, very recommended.
For now, the price is the main reason for the popularity of the impact of NAS, NAS hardware threshold is not high, the flagship software services is not much technical barriers, I believe in the future as Internet companies such as millet prices butcher like involved, NAS the price will be reduced to the level of ordinary people can buy experience, to then NAS might like removable hard disk to become one of the electronic devices an integral part of the life.
I use Synology introductory paragraph Double bit NAS - DS218J, hard disks raid1 two 2T achieve data redundancy to ensure data security. Conveniently from any terminal (laptop, desktop, mobile phone, ipad) access, on the phone Photo by DS a key backup all cell phone photos, save a lot of money to buy iCloud.
NAS and computer data transmission is taking the cable, the transfer speed will receive the impact of cable bandwidth, Fast Ethernet cable theoretical transfer rate of 12.5MB / s, run over should not be a problem, Gigabit Ethernet cable theoretical transfer speed of 125MB / s, see it is not low, with almost theoretical transfer speed between the hard disk. So read and write speed of the NAS What factors do, how to achieve the theoretical speed of it? In my opinion the following main points:
1, Gigabit Ethernet Fast network VS
Above that, ten times the bandwidth of Gigabit Ethernet is Fast network, our next test is really how the case, first test under the Fast network, using Mercury 100M switch, the computer and NAS are connected to the Fast switch .
Fast network can be seen in the environment, taking into account various losses, the hard disk read and write speed 11MB / s, has substantially run over the bandwidth of the Fast, Fast network has apparently not feed the full NAS.
Then replace the Gigabit network test, using high-end Asus AC-66U Gigabit Router, the figure is currently my dorm actual topology of the network. Dormitory broadband networks are generally tens of megabytes, so use an ordinary Fast switch is enough. Since I have both the campus network needs (under ipv6 video, school resource access), another telecommunications network needs (play games, watch video fast), on the whole had a MT-VIKI of RJ45-2 network switch. SWITCH When switched to the telecommunications network, NAS through a router on and connected to the computer. Computers and NAS data exchange is taking the two-story Gigabit router, a layer of Fast switch will not be affected.
Mutual transfer files between the computer and the NAS measured speed of 100MB / s, substantially close to the limit line of Gigabit Ethernet speed is 50MB / s copying between the different partitions are twice the same drive speed.
Transmission speed Gigabit networks is satisfactory, indeed ten times the speed of Fast network. Well Gigabit network it? Although Gigabit Router, Gigabit LAN Gigabit network cable and are more expensive, the market is still there to sell, then put all Gigabit NAS device can significantly improve read and write speed of it? The answer is disappointing, because the barrel theory, the transmission speed is limited by the lowest speed of the device under Gigabit network environment, the actual read and write speed is limited by the speed bottleneck 150MB / s of mechanical hard disk.
Well into the fastest SSD read and write it? Hey, someone really did so! Yi Wang B station on a Gigabit network DIY the NAS, the NAS and the host card Gigabit fiber directly connected, under the action of the memory cache, the copy speed of the small files 1GB / s, was so cool! Although mechanical disk or copy files be limited by the speed of mechanical disk itself, but the network does not become a bottleneck, and a few hard test will not go in conflict.
So, again ten times faster, using the 100G network do? Yi Wang and did so! After using a dual port NIC 56G 10 Gigabit link aggregation build broadband. Of course, the cost is very high, the bandwidth of the optical cable support 56G have one meter 200, and then double the price requires two work together aggregation. 56G just a single interface to read and write speed conversion under Windows has 6000MB / s, while reading NVMe solid state we usually use only 3000MB / s and 2000MB / s write, the fastest solid state drives have been not enough. ..... then it can only be used when the hard disk memory! Yi Wang the six points of the memory 8G, when each side of 24GB hard disk.
By the system kernel, CPU performance, and other restrictions, file transfer can only run single channel point to point, do not even link aggregation, the software is still running out of 5700MB / s achievements.
Directly through the Task Manager to copy files, reaching 2GB / s, this time bottlenecks appeared in the Explorer body, and it requires real-time display the remaining time and the speed of replication, file verification, and more to do.
Now transfer speeds are based MB / s as a unit, I believe that in the near future, just like MB / s to replace KB / s as, GB / s and TB / s will become routine now!
2, VS six UTP cable:
UTP lines may transmit gigabit network, taking into account transmission losses, then it is below the gigabit. Category 6 cable performance can be provided twice in the UTP cable, and has a smaller cross-talk, return loss should be much better. Category 6 cable then replaced the words will not enhance the transmission speed between the NAS and the computer?
I do not have Category 6 cable, looking for a look at the online test.
You can see the transmission speed UTP cable and six cable basically no difference, why is this so? First, the inherent mechanical hard disk speed bottleneck is unable to break through, at most, replaced by six cable run over gigabit network limits. Secondly, for a home network over five lines already enough, in short distance speed difference over five lines and six lines on the index is not so obvious, more in long-distance transmission will reflect the gap . In short, it is: for cable futile.
3, link aggregation technology
Link aggregation refers to aggregation plurality of physical ports together to form a logical port for incoming / outgoing traffic at certain load sharing among the member ports, the network packet switch sharing policy decisions based on the port from which the load member ports configured by the user sent to the peer switches. When the switch detects when one member port link fails, it stops sending packets on this port, and share strategies in the rest of the recalculated link packet transmission port, according to the load port after the failure to restore the reappointment send and receive ports. Link aggregation increase the link bandwidth for transmission elasticity and redundancy engineering and other aspects is a very important technology.
On the NAS polymerization of said link is to use two cables simultaneously to your PC, NAS and the router connected together, each of the cable share half. So that we can achieve double the bandwidth, provided that your NAS, routers, computers need to support link aggregation (there are two Ethernet ports).
However, link aggregation technology is just double the bandwidth , and single-user transmission rate can not be achieved doubled. Is suitable for multiple users to access the NAS usage scenarios, such as two computers simultaneously access the NAS, each user has a 100MB / s speed, do not conflict. If a single user access is only 100MB / s Gigabit Ethernet speed limit.
4, NAS Summary
To enhance the transmission speed of the home NAS, the most important thing router performance. Gigabit Ethernet is essential, so pick a better and faster Gigabit Router now!
Fourth, Full Summary
Agreement with the table is the speed associated with the hard disk summary, the current hard disk products is the fastest lightning 3, the transmission speed of 40Gbps makes it possible bis 4K (4096 × 2160) 60Hz monitor output, or external GTX2080Ti graphics. Then the memory is fast, then, DDR3 1600Mhz memory bandwidth is the speed of 1600Mhz * 64/8 = 12.8GB / s, Yi Wang take the above-mentioned memory so that when the hard disk, read and write speed easily break 5GB / s.
Optional mechanical hard disk, then try to avoid shingled , the solid state hard drive have to look M.2 interfaces go a SATA channel or PCI-e channel , the motherboard does not support it to buy a reliable SATA interface SSD. U disk nothing to say, like the election of the USB3.0, U disk USB3.1 interface currently lacks necessary, after all, most of the computer is only USB3.0 interface blue inner core, the popularity of the motherboard such as the future the Type-C interface to talk about it.
The actual transfer of hard drives related to many factors, the reading speed is much faster than writing speed . Finally, a product table actually common speed is the best product currently do under the best environment ideal speed, and in most cases the use is not up to the speed, but the minimum should be able to reach seven or eight into it, if your product and the list of parameters too much difference, you have to check the next in the end the problem in which part of the.
Finally I wish you all faster and faster!
Qin daily backup repeat Oh, thank you watch
