What Is Cable Length Testers?

Optical fiber communication is a communication mode with optical wave as carrier and optical fiber as transmission medium. Optical fiber communication has become the main means of information transmission and the cornerstone of "information highway" because of its long transmission distance, large information capacity and high communication quality. Optical fiber testing technology is the most extensive and basic special technology in the field of optical fiber applications. OTDR is the main instrument in the field of optical fiber testing technology. It is widely used in the maintenance and construction of optical fiber lines. It can measure the length of optical fiber, transmission attenuation of optical fiber, joint attenuation and fault location. OTDR has the advantages of short test time, fast test speed and high test accuracy.1. Two basic formulas supporting OTDR TechnologyOTDR (optical time domain reflectometer) is a high-tech and high-precision photoelectric integrated instrument made by using Rayleigh scattering and Fresnel reflection when optical pulse is transmitted in optical fiber. The semiconductor light source (LED or LD) outputs light pulses modulated by the driving circuit, which are injected into the tested optical cable line through the directional optical coupler and movable connector to become incident light pulses.When the incident light pulse is transmitted in the line, Rayleigh scattered light and Fresnel reflected light will be generated along the way. Most of the Rayleigh scattered light will be refracted into the cladding and attenuated. The back Rayleigh scattered light opposite to the propagation direction of the light pulse will be transmitted to the light inlet port of the line along the optical fiber, and will be transmitted to the photodetector through directional coupling shunt and converted into electrical signals, After low-noise amplification and digital averaging, the processed electrical signal is scanned synchronously with the trigger signal emitted from the back of the light source and becomes a reflected light pulse on the oscilloscope.The returned useful information is measured by the OTDR detector, and they are regarded as time or curve segments at different positions in the measured optical fiber. According to the time from transmitting signal to returning signal, and then determine the speed of light in quartz material, the distance (fiber length) l (unit: m) can be calculated, as shown in formula (1).In formula (1), n is the average refractive index and â–³ t is the transmission delay. The attenuation a (unit: dB / km) can be calculated by using the power level corresponding to the incident light pulse and the reflected light pulse and the length of the measured optical fiber, as shown in formula (2):2. Five parameter settings to ensure OTDR accuracy2.1 test wavelength selectionSince OTDR serves optical fiber communication, the test wavelength shall be selected before optical fiber test, and only 1310 nm or 1550 nm shall be selected for single-mode optical fiber. Since the influence of 1550 nm wavelength on the bending loss of optical fiber is much more sensitive than 1310 nm wavelength, 1550 nm wavelength is generally used to test the whole process optical fiber backscattering signal curve of an optical cable or an optical fiber transmission link, whether it is optical cable line construction, optical cable line maintenance or experiment and teaching.The shapes of the test curves at 1310nm and 1550nm are the same, and the measured fiber connector loss values are basically the same. If no problem is found in the 1550 nm wavelength test, the 1310 nm wavelength test is certainly no problem.If the 1550 nm wavelength is selected for testing, it is easy to find out whether there is excessive bending in the whole process of the optical fiber. If a large loss step is found somewhere on the curve, retest with 1310 nm wavelength. If the loss step disappears at 1310 nm wavelength, it indicates that there is excessive bending at this place, which needs to be further found and eliminated. If the loss step is also large at 1310 nm wavelength, there may be other problems in the optical fiber, which need to be found and eliminated. In the test of single-mode optical fiber line, 1550 nm wavelength should be selected as far as possible, so the test effect will be better.2.2 optical fiber refractive index selectionThe refractive index of the single-mode optical fiber used now is basically in the range of 1.4600 1.4800, which should be accurately selected according to the actual value provided by the optical cable or optical fiber manufacturer. For G.652 single-mode fiber, if 1310 nm wavelength is used in actual test, the refractive index is generally 1.4680; If 1550 nm wavelength is used, the refractive index is generally 1.468 5. Incorrect selection of refractive index will affect the test length.In equation (1), if the refractive index error is 0.001, an error of about 35 m will be generated in the relay section of 50000 M. Small mistakes in optical cable maintenance and troubleshooting will bring obvious errors, which must be paid enough attention during testing.2.3 selection of test pulse widthIf the set light pulse width is too wide, strong Fresnel reflection will be generated, which will increase the blind area. Although the narrow test light pulse has a small blind area, the test light pulse is too narrow, the power must be too weak, the corresponding backscattering signal is also weak, the backscattering signal curve will fluctuate, and the test error is large. The set optical pulse width shall not only ensure that there is no strong blind spot effect, but also ensure that the backscattering signal curve has sufficient resolution and can see each point along the optical fiber.Generally, an appropriate test pulse width is selected according to the length of the measured optical fiber, and an optimal value is determined after one or two trials. When the distance of the measured optical fiber is short (less than 5000 m), the blind area can be less than 10 m; When the distance of the measured optical fiber is long (less than 50000 m), the blind area can be less than 200 m; When the distance of the measured optical fiber is very long (less than 2500 000 m), the blind area can be up to more than 2000 m.In the single disk test, the blind area can be less than 10 m by properly selecting the optical pulse width (50 nm). If the average value is obtained through two-way test or multiple tests, the impact of blind area will be less.2.4 selection of test rangeThe range of OTDR refers to the maximum distance that the abscissa of OTDR can reach. During the test, the measuring range shall be selected according to the length of the measured optical fiber, and it is better that the measuring range is 1.5 times the length of the measured optical fiber. If the range selection is too small, it can not be seen comprehensively on the display screen of the optical time domain reflectometer; When the range selection is too large, the abscissa compression on the display screen of the optical time domain reflectometer can not be seen clearly.According to the practical experience of engineers and technicians, the selection of test range can make the backscatter curve account for about 70% of the OTDR display screen, whether it is length test or loss test, better direct viewing effect and accurate test results can be obtained.In the test of optical fiber communication system, the link length is hundreds to thousands of kilometers, the relay section length is 40 60 km, and the single optical cable length is 2 4km. Good test results can be obtained by selecting the range of OTDR.2.5 selection of averaging timeBecause the backscattered light signal is extremely weak, the method of multiple statistical average is generally used to improve the signal-to-noise ratio. OTDR test curve samples the reflected signal after each output pulse, and averages the multiple samples to eliminate random events. The longer the averaging time is, the closer the noise level is to the minimum value, and the larger the dynamic range is. The dynamic range obtained with an average time of 3 min is 0.8 dB higher than that obtained with an average time of 1 min.Generally speaking, the longer the averaging time, the higher the test accuracy. In order to improve the test speed and shorten the overall test time, the test time can be selected within 0.5 3 min.In the connection test of optical fiber communication, satisfactory results can be obtained by selecting 1.5 min (90 s).3 three common methods of OTDR testingWhen OTDR tests optical cables and optical fibers, the test occasions include factory test of optical cables and optical fibers, construction test of optical cables and optical fibers, maintenance test and regular test of optical cables and optical fibers. The test connection of OTDR is shown in Figure 1.The test connection method is: OTDR - optical fiber connector - the first optical cable - the second optical cable - the nth optical cable, and the terminal is not connected to any equipment. According to the actual test work, there are three main methods:3.1 OTDR backward test methodThis method is mainly used to monitor the optical cable connection. The optical cable connection must be equipped with a special optical fiber fusion machine and optical time domain reflectometer (OTDR). After welding a fiber core, the welding machine will generally give the estimated attenuation value of this contact. This method of testing has three advantages:(1) OTDR is fixed, omitting the vehicles and a lot of manpower and material resources required for instrument transfer;(2) The test point is selected in the place where there is mains power without gasoline generator;(3) The test points are fixed to reduce the stripping of optical cables.At the same time, this method also has two disadvantages:(1) Due to distance and terrain constraints, it is sometimes impossible to ensure smooth communication;(2) With the continuous increase of connection distance, the test range and accuracy of OTDR are limited.At present, there are generally three methods to solve these problems:â‘ The use of mobile phones in the city and suburbs can keep the testers and successors in touch at any time, facilitate organization and coordination, and improve work efficiency.â‘¡ Contact by telephone. Make sure to connect one optical fiber (such as blue optical fiber unit and red optical fiber) to the optical telephone as the connecting line. Of course, the last optical fiber used for communication cannot be monitored because it cannot be contacted during fusion and fiber winding. Even so, the possibility of problems will be greatly reduced (if it is a 24 core optical cable, the probability of problems will be reduced to less than 1 / 24 of the original).â‘¢ When the optical cable connection reaches a relay distance, the OTDR moves forward.The test practice shows that these monitoring methods are effective to ensure quality and reduce rework.3.2 OTDR forward one-way test methodOTDR is tested at the first joint point in the optical fiber connection direction, and construction vehicles are used to transfer the test instruments and testers in advance. Using this method for monitoring, the test point and connection point always have only one disc of optical cable length, the attenuation accuracy of the test joint is high, and it is convenient for communication. At present, the length of one optical cable is about 2 3 km. In general terrain, communication can be ensured by using walkie talkie. If the optical cable has a corrugated steel strip protective layer, you can also use the magnet telephone to contact.The disadvantages of this test method are also obvious. Moving OTDR to each test point is labor-consuming and time-consuming, which is not conducive to the protection of instruments; The test points are also limited by the terrain, especially when the line is far away from the highway and the terrain is complex. Portable OTDR is selected for monitoring. The short-range test does not require high dynamic range of the instrument, and the small 0tdr has small volume, light weight and convenient movement, which can greatly reduce the workload of testers and improve the test speed and work efficiency.3.3 OTDR forward two-way test methodThe OTDR position is still the same as the "forward one-way" monitoring, but two optical fibers are respectively short circuited at the beginning of the connection direction to form a loop. This method can not only meet the optical fiber test of relay section, but also monitor the optical fiber connection. When testing the optical fiber in the relay section, the incident light pulse, reflected light pulse, joint point, fracture point, fault point and attenuation distribution curve can be clearly seen on the display screen of the optical time domain reflectometer. The OTDR test event type and display are shown in Figure 2, which can provide convenience for optical cable maintenance.When monitoring optical fiber connection, due to the increase of loopback point, the bidirectional value of connection loss can be measured on OTDR. The advantage of this method is that it can accurately evaluate the quality of the joint.Due to the test principle and optical fiber structure, there will be false gain and false large attenuation in one-way monitoring with OTDR. For an optical fiber connector, the mathematical average of attenuation values in two directions can accurately reflect its real attenuation value. For example, the attenuation of a connector measured from a to B is 0.16 dB, and that measured from B to a is -0.12 dB. In fact, the attenuation of this connector is [0.16 (- 0.12)] / 2 = 0.02 dB.4 ConclusionAs the main instrument of optical fiber communication,

WireMap - WireMap tests to ensure that the cables are connected from pin to pin according to the standard of connection. Testing the wiring of a UTP / Cat 5E / 6 / 6A cable with the full scope of the cable to check its performance is very important.This term is used by manufacturers and testers to mean that the cable is tested to pass one of the CAT 5E, 6 or 6A certifications, and the tester tests the standards set in the performance parameters.These are the standards that the testers use for those who want to check the quality of their cables. Professional network testers are used in commercial environments and are used to certify that professional cable installers are working properly. Certification audits are a way for installers to ensure that the cables that go into the network meet TIA and ISO requirements.These qualification testers meet the needs of network technicians who install new cabling not only but also to troubleshoot network operations. Professional testers have more skills when it comes to troubleshooting cables while maintaining high accuracy. Qualification testers conduct tests to determine whether existing cabling in a connection meets the requirements for fast Ethernet, 100base-TX, VoIP (VoIP) and Gigabit Ethernet.You can test the cable performance of your home network (telephone cable, fiber optic cable, etc.). With the help of a qualification tester. Test your network cables as best you can with a network cable tester to get the job done. By connecting both ends of the cable, the tester takes on the task of making an accurate measurement for you of whether your cable is working or not.If you make your own cables, such as installing our own RJ45 BNC ends, we want to ensure that the cables are properly wired. With patch cables of Cat 6 and 6A, which are more than 20m long, we test according to the 20m standard, because we do not have a program that limits the number of longest cables. If you need a transfer speed of 1 Gbit / s, check that the cable has the properties to support it.If we attach the cables separately, the cable tester will find out where the cables come from and he will show me where pins 1, 2, 3.4 and 5 are so that they are wired correctly. If there is a crossover cable, the pins 4 and 5 are not correctly wired : 1 / 3 is swapped, 2 / 6 is swapped and 2 / 6 is at the other end of swap 1 / 3.The purpose of one of these tests is to find out if the cable is within the ballpark length of the max switch test, and if so, fine. If I carry a full-length cable and the switch says it is 310, it is a stroke of luck and I read 347 as the specification. When I used the original simple tester, I noticed something about it, and it told us that we had a bad cable.Since the LAN's transmit high-speed signals through the cable, the attenuation of the cable is a variable frequency signal, and certification testers must test at multiple frequency lines at multiple frequencies as specified in the specification 568. To do this, the tester must have at least one of them calculated and recorded at the end of the cables (the transmitting and the receiving).The specification limits the return losses not only to the length of the connecting cable, but also to the way in which the same pass / fail limit applies to the length of the cable. If the short distance change is too small a limit to be a stroke of luck, I recommend that we test the limit by setting up a shorter cable to be tested. In the case of longer cables, the limitation to crosstalk is loosened in addition to the different length.Test tools do not provide bandwidth readiness information for high-speed data communication. Verification tools should include additional features such as a time domain reflection (TDR) to determine the length of cable and the distance to interrupt a short circuit. The device should export the test results to a printable format with the required documentation.Ethernet cable testers, whether they call themselves testers or testers, do not need to measure the entire range of ANSI or TIA performance indicators required to accelerate and certify an Ethernet cable. Some failed ones generate quasi-certification reports with test field parameters that require the use of a digital signal to perform the test. They have less insight into the cable length without warning of potential problems, such as edge termination, which can cause problems reaching 10 gigabits.Your cable test reports are generated by our Fluke DTX-1800 cable tester and associated Fluke Linkware software. In order to explain how they are created and the meaning of the values and diagrams shown in them, we need to go into the specifications a little.A cable tester is an electronic device used to check the electrical connection between a signal cable and other wires in a module. The most basic cable testers are through testers that check for the presence of a conductive path between the ends of a cable and check the correct cable connectors on the cable. More advanced cable testers measure cable signal transmission characteristics such as resistance, signal attenuation, noise and interference.A network cable tester is a revolutionary device designed to test cable connections for functionality and reliability. It is a must for network technicians, network testers, cable testers and other related work to this area. A simple wire harness is a battery-powered portable instrument that draws electricity from one or more voltage indicators in a switching / scanning arrangement and checks several conductors simultaneously.Nevertheless, network and cable testers in this industry are essential for homeowners because they can help avoid network problems and maintain home cable connections. A reliable cable and network tester is able to fix problems and help you identify cable problems and connection problems.In this post, Comptia Network Instructor Rick Trader shows some of the most popular cable testers and how to use them in a network configuration. Now that we have covered cable connectors, let's take a look at the tools we can use to test our various cables in our environment.

Today there are many different manufacturers and types of network cable testers on the market. Standard testers are used by those who want to check the quality of their cables. Bridge cables are a one-piece technology and are often used by certification testers as they can perform a greater variety of tests and there are short training videos on how to use them.Professional network testers are used in commercial environments and by certified professional cable installers at work. Professional testers have more skills when it comes to troubleshooting cables while maintaining a high level of accuracy. As an added bonus, professional testers allow you to track and archive your test results for future references.Some verification tools contain additional features such as a Time Domain Reflectometer (TDR) to determine the length of the cable and the distance between interruptions and short circuits. Some test tools do not provide information about bandwidth or suitability for high-speed data communication.There are many different types of network testers on the market today. LinkIQ cable network testers are easy to use, as explains Eric Webb, Fluke Network Product Manager in the video below. It shows how the settings can be used to perform a cable test with a network cable tester, save the results and upload them to link ware where they are available.To help you find the best network or cable tester for your use, I have compiled a list of test products that work well. The most obvious difference between a generic or standard tester and a professional tester is the brand cost, where professional network testers are more expensive than other testers.I came across the Elegiant Network Cable Tester while working on establishing a LAN connection for a local company. With my extensive experience as an electrician, I can say that this is the best tool for testing cable connections.Selecting, selecting and purchasing a suitable network cable tester can be a complicated and challenging task. However, there are some essential factors that consumers should consider when purchasing a good network cable tester and absolutely should consider, as they can make or break the tester you are buying.For example, suppose you are looking for a good Ethernet cable tester or Ethernet cable speed tester. Network cable testers are sensitive products that are exposed to various extreme elements, suggesting that you should get a tester with a long warranty. In this case, you should look at the reviews of the Ethernet cable testers from previous buyers, who can confirm the star rating of the products.These three basic tests are performed in accordance with the EIA standards for twisted pair cables, wire mapping and cable length for high-speed performance. Check that the signal is strong and fast enough to meet network performance requirements. If you are testing the cable length with a calibrated capacitive tester it is better to test with a time domain reflector tester, as it can measure the distance to the location where the error is displayed.Make sure that the two ends of the cable you want to test are not connected to a TV, cable distributor, or any other related device. Find the right cable and touch the cable to one or the other so that a beep is generated. Connect one end of the coaxial cable tester to the wall plate on your coaxial cable wall and point the other end to the tester so that the entire cable can be assembled.This situation is indistinguishable from a real insulation break when the triggering current is exceeded. As the length of the cable increases, its capacity is limited by the rise time. The shorter the rise time, the higher the voltage, and the larger the DV / DT, the greater the amount of current required to charge the cable (parasitic capacity). Increasing the wire resistance of a longer cable helps to slow the charging current but requires a minimum dwell time of 10 s to ensure that the full cable length is reached before the test voltage is performed (leak measurements).Dirty contacts, bad bruising, cable damage and poor quality can provide strange and wonderful reading results. In order to reach the test voltage without damaging the traction current, it should be taken care to adjust the voltage ramp to the length of the cable so that it slows down. Cami Research ramp tester has a ramp which can be adjusted from 150 V / s to 5,000 V / s.The flagship cable tester VDV-II Pro uses a TDR to measure cable length and provide distance and error information. A TDR works by injecting a signal into the cable and measuring the time the signal reflects an impedance change caused by a short circuit.Standard testers are manual, while professional testers work automatically. Automatic testers allow you to apply contrasting IA- and ISO-testing methods and highlight many individual tests to verify conformity.The PocketHornet comes standard with a limited warranty of 1-2 years, depending on the region. Customers in the EU receive a 2-year warranty, while others only receive a 1-year warranty. It is not a cable certification device, but conducts cable qualification and verification.There are various types of cables on the market, but the most popular and widely used cable for modern technology is the coaxial cable. This article describes how to test a coaxial cable signal with a multimeter in situations where the transmitter does not work well. We may receive a small commission if you purchase a product through our selected links but the price of the product remains the same.In a house with a wired network connected to the TV, the cable coming from the family room should connect to a cable modem or router upstairs. There are 2 cables in the family rooms, the one marked "upstairs" is connected to the office upstairs and the other "downstairs" to the basement.

The LinkRunner LTRA offers a variety of cable testing techniques, including TDR, wiremapping, office identification and toning. The LTRA is designed to help troubleshoot wiring problems such as excessive cable routing, cable breaks, wall panels, patch panels, etc. It uses a combination of TDR and resistance measurements to map the wire, measure cable length and detect anomalies such as short, open or split pairs.The LRAT can measure an accurate cable length of 100 m or less with an accuracy of plus or minus 2 m. It can also be used to test terminated cables connected to an internal cable mapping port (WMAP) or an external cable identification accessory, as well as undermined and open cables. For pre-assembled and non-assembled cables, the fault detection is accurate to within 0.8 m of the error distance.This tester is a wiremapper that checks connections for CAT 5E / 6 certification, but can also test performance at higher frequencies. The threshold for the low voltage resistance is set insulated for 5 mO to a contact resistance of 0.1 O. This is measured with an embedded resistance at 100 O (1 mO x 1) to achieve an accuracy of less than -0.1 o (5 mO).In fact, certification testers can test wire diagrams, length attenuation, and crosstalk from one connection to another, helping you troubleshoot and save the results in a printed report for the customer. Cable certification testers are automated, so it's so easy to get a pass or fail at the touch of a button. Installers use certification testers to test cables that are being laid.There are a large number of cable testers on the market today, which means that there may be the right device for your purposes. To help you find the best network cable tester for your use I have compiled a list of test products that work well. As someone with extensive experience as an electrician, I can say that the Elegiant Network Cable Tester is the best tool for testing cable connections.I came across the Elegiant Network Cable Tester while working on establishing a LAN connection for a local company. As a consumer, I used the handheld network cable tester with RJ11, RJ12, RJ45 for the Cat 3 types Cat 5E, Cat 6 and Cat 6A. The broad compatibility of the device does not complicate your work in the analysis of cable connections.Cable Prowler (tm) provides complete cable testing for all categories of network, coaxial and telephone cables. Selecting, selecting and purchasing a suitable network cable tester is a complicated and challenging task. Purchasing the right network cable tester can save you a lot of inconvenience and trouble.Includes low-voltage and high-voltage subsystems, HVX-compliant automation, enabling extended testing of insulation resistance, dielectric breakthrough, Zener diode breakthrough, voltage upgrade, 4-wire measurements, and advanced measurements. With the changing landscape of corporate cabling, there is a demand for testing equipment you can rely on. Hopefully this article has helped you choose the best network cable tester for your profession and field of work.Advanced measurement options provide increased x5 / 2 wire resistance resolution for backplane, complex networks, capacitors, wire pairs, capacitors, twist pairs, and cable length testing. Copper remains the first choice for telephone data and video lines. Integrated Intellitone digital / analog tones are located on the cable or wire pair in the active network.It is an expensive device that requires trained operators and many failures due to problems with the wirecard. Other crews use low-cost cable ties to ensure the connections are correct before the certification tester is turned on. Instead of letting the crew find and fix their own wiremap problems, tests and fixes can be made before the cable is installed, and tester costs are not wasted on simple problems.

If the cable insulation is damaged or aging, short circuit, disconnection, grounding and other faults may occur in use, affecting the safe operation of the power system. Power cable plays an important role in power transmission and distribution system, so it is of great practical significance to detect power cable faults regularly or irregularly. Here is a popular science about common power cable test methods. AC withstand voltage test of main insulation (series resonance test equipment) is an effective method to test the ability of cable insulation to withstand various overvoltage. It is a strict, direct and effective test method to determine the insulation strength of cable. Cable fault location and cable path identification: the cable fault detector system is composed of cable fault detector, high voltage pulse generator, pointing instrument and cable comprehensive detector, which is used to detect cable low resistance, short circuit, open circuit fault, high resistance leakage and high resistance lightning fault, correct direction and depth of underground cable and locate open circuit, short circuit and skin fault points of cable. Partial discharge inspection: different from using ultrasonic detector products to detect common transformer partial discharge, vibration wave partial discharge detection is used for cable partial discharge. This detection method is based on LC damping vibration principle and uses attenuated vibration wave voltage with frequency in the range of 20-800hz instead of working frequency AC voltage detection equipment. It is mainly used to detect the main insulation For the insulation condition of the joint and terminal, its waveform and frequency are close to the sine wave of the working frequency, the action time is short, and will not cause damage to the cable. Infrared temperature measurement: the infrared thermal imager uses the infrared thermometer and optical image mirror to receive the infrared radiation energy distribution pattern of the temperature measurement target, which is reflected on the photosensitive part of the infrared thermometer to obtain the infrared thermal image map. The thermal image map corresponds to the thermal distribution field on the object surface, and the infrared thermal imager is used to detect the infrared radiation signal on the cable surface. The cable identifier manufacturer summarizes the common power cable detection classification. In practical application, power cable detection is closely related to insulator detection. Usually, various insulator fault detectors, insulator distributed voltage detectors and other products need to be used to detect various faults of insulators, especially in the annual spring detection of power companies, such as power cables, switchgear Transformers, overhead lines, insulators and various fittings shall be systematically tested to ensure the safe operation of the power system as a whole.

The introduction of cable trackerA cable tracker is a device used for broadcasting TV signals on various cable systems. It has the ability to detect if there is an incoming signal, and then start broadcasting it.Tips for cable trackerMost of the cable TV companies are aware of the importance of attracting viewers to their show. While it's not unusual to see ads for cable television stations and channels running at top slots, what is uncommon is to see advertisements from a different perspective.How to use cable tracker?Cable tracker is a common piece of software used by people to find cable TV channels. It helps you identify different cable channels based on recordings you have also found online.The specifications of cable trackerCable tracker is a device used in cable TV to obtain information about the transmission of a signal from the cable.The product instructions of cable trackerWe should not just buy a cable or satellite tracker but understand what is it to use it in the most effective way.The application of cable trackerCable trackers are a form of instant communication that can connect you with your business partners and clients. By using this tool you can find out about their jobs, responsibilities, location and social media account holders.

In The Almost People, and The Eleventh Hour, the Doctor's screwdriver is destroyed and later regenerated. However, in The Day of the Doctor, the Doctor(s), run a calculation running over 400 years. How is this possible, if the screwdriver was destroyed between the start and finish? This is technically trivial. Anyone running a very long computation (and some real computations can last for weeks) will regularly save the state of the computation on some reliable medium that does not need power, so that the computation can be restarted after any kind of failure. Actually there can even be several levels of back-up, balancing reliability and cost.The computation does not need to be restarted with exactly the same software, as long as the intermediate results that have been saved can be interpreted and reused by the new software. Actually this can even be a way to improve the software (or the hardware) while the computation is on-going. This is standard technology, even for people who are not time-lords.The screwdriver could simply save its state on the Tardis whenever there are close enough to communicate by whatever means. It could also be saved in various places known to be stable in time by someone who travels through time.If the screwdriver is destroyed, only that part of the computation done since the last back-up is lost and must be redone.By the way, since the Doctor travels through time, he could well organize the computation and back-up to get a lot more than 400 years worth of computation, depending on the structure of the algorithm and the computational capacity of the screwdriver.It is to be expected that the computation does not take all the computational power of the screwdriver. If a computational thread actually leaves a lot of untapped computational power, it can be parallelized with a future fragment of the same thread by getting from the future the starting state for the later thread. Time travel extends the possibilities for parallelizing computations. OTHER ANSWER: Like Rose said in The Day of The Doctor" Same Software different case"Therefore the Doctor's screwdriver was not completely destroyed, only the case containing it was; the software was safe making it possible for the TARDIS to repair the case and give the Doctor a seemingly "new" screwdriver with the computation still intact

On website there are programming languages, statements about them and voting that associates languages with statements. In particular, there are statements: "This language is built on a small core of orthogonal features" "This is a mainstream language" Why they are so opposed to each other? Is being incoherent, history-encumbrant, ridden with extra special cases a must for being popular, "mainstream" programming language? Maybe is it similar reason as why beautiful and coherent artificial natural languages (like Esperanto) are not that popular? There are three reasons why you learn a natural language:As it happens, the languages you'd learn under point 3 are ususually not spoken in public or at home, and are not taught in school in place of French or Spanish. Therefore, they are all very niche.Oh wow, so A and B seem to have some correlation. Does A cause B? Or the other way round? Or are there other factors that I didn't consider?Your question seems to ask if a programming language can only become mainstream if it is not orthogonal. This is misleading. Languages change over time. Their standard library gets reworked. New syntax is added. Object orientation is made available. Lambda expressions start looking useful. But closures and objects can be implemented in terms of each other, so why would I need both? Why would I want generics or other type system additions? I clearly do not need themA language that does not evolve is probably dead.For some languages, practicality is of utmost importance. It doesn't matter if there are five or more screwdrivers in my toolbox, because not all screws are equal. An experienced user will pick the right one for the situation.Other languages strive to be more minimal and/or elegant. This can be useful for didactic purposes, or in research settings. Small languages are easier to port. They are often useful, but not always when you have to ship your application yesterday.A language that tries to be relevant tomorrow has to keep evolving, and include new concepts. For example, the C standard is slowly but constantly being reworked. Each release of Java is a step forward. C# is often ahead of the pack as far as mainstream languages go. A language like SML or Smalltalk has no serious ambitions to go mainstream.A language that already is widely used has to stay backwards compatible, or it will loose market share. Features that were there yesterday have to stay available even if a better alternative was introduced. In Java, type parameters are erased during compilation for back-compat. In PHP, the main namespace is riddled with dangerous and deprecated functions that can't be removed without breaking a good part of the internet. I would suggest that successful languages tend to become less orthogonal over time, not only that less orthogonal languages tend to become mainstream more easily. However, there is no clear causation because there are more factors to consider.If I look through the list of languages you linked to we see as orthogonal languages: Scheme and Lua had minimalism as a design goal, academic languages like Coq, Haskell, SML are less useful for day-to-day programming or difficult to learn, and some languages like Forth and APL are barely used any longer. The less orthogonal languages are all quite mainstream, or have a long history. Fortran and COBOL are ancient, but still have a strong niche. Languages like PHP and Shell grew beyond what they where intended to do. Some languages are explicitly pluralistic, e.g. Perl and its descendant Ruby. The C# language is in direct competition to Java and tries to score with better features. Some languages have a religious commitment to backcompat, e. g. C or Perl. OTHER ANSWER: Because reducing the feature set of a language requires a compromise. Taking a feature out of the language means either:the language no longer has that feature, so people who need/value that feature will not want to use that language (aside: this is the reason I've never tried golang. while I like some of their ideas I find exceptions too useful to abandon), orthe feature must be implemented as a library within the language. But it is hard to design a language such that a wide variety of useful features can be implemented without compromising on syntax, and syntax is critical in gaining market share (if it wasn't, we'd all be using LISP by now).LISP is a good case study: it is built on an extremely small set of basic primitives, and those primitives can be combined and recombined in very useful ways, such that just about any language feature you can think of can be (and probably has been) implemented in LISP somewhere. Unfortunately, in order to become flexible enough to achieve this, LISP has compromised on almost all syntactic niceities, leaving a language that (to put it bluntly) only hardcore hackers can stand using. I'm not suggesting that this is the only way to make a small core language do useful and interesting things, but certainly it is harder to do it without making such compromises. And given that language success is a hit-and-miss kind of thing, ruled by primarily by what developers are trying to do that their existing languages don't do nicely and a new language might do better, the size of the core doesn't really figure much in whether a language becomes popular. And because making a nice language with a small core is more difficult than sacrificing either of those features, fewer such languages are made, which makes it substantially less likely (due to the law of averages) that they will gain traction.

The introduction of wire testerThere is a wide variety of different tools and methods for writing good introductions, and all of them have their own pros and cons. Some are easier to use than others, some require more technical skills than other methods. Most importantly, the introduction should make an immediate impact on the reader's mind.Tips for wire testerAfter completing the wire tester test, it is important to understand why it was executed as per the plan.How to use wire tester?A wire tester is a tool for testing websites. It helps identifying vulnerabilities and performance issues in the website.The specifications of wire testerWire tester is responsible for the quality of an electronic product at the end of its delivery process.The product instructions of wire testerThe instruction manual and the guide are two different things. They are two sides of the same coin. If it is not properly written, then you can't expect to get a high-quality product.The application of wire testerThe application of wire tester is very useful for testing a project before you start working on it. It can also be used to find common problems and glitches in the project that may otherwise go unnoticed during the initial development.

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