L2 vs. L3 cache: What’s the Difference?

The cache is a special buffer memory that is located between the memory and the processor.

So that the processor does not have to get every program command from the slow memory individually, a whole command block or data block is loaded into the cache. The probability that the subsequent program instructions are in the cache is relatively high. Only when all program instructions have been executed or a jump command to a jump address outside the cache, the processor must access the memory again. Therefore, the cache should be as large as possible so that the processor can run the program instructions one after the other without waiting.

Typically, processors work with multi-level caches that are different in size and fast. The closer the cache is to the computing core, the faster it works.

Inclusive cache and exclusive cache

With the multicore processors the terms inclusive and exclusive cache came up. Inclusive cache means that data in the L1 cache is also present in the L2 and L3 cache. This makes data consistency between the cores more secure. Compared to the exclusive cache, some storage capacity is given away because the data is redundant in the caches of several CPU cores.

Exclusive cache means that the cache is available to a processor core exclusively, that is, for it alone. It does not have to share the cache with another core. A disadvantage of this is that several processor cores can then exchange data with one another only by way of a detour.

L1 cache / first-level cache

As a rule, the L1 cache is not particularly large. For reasons of space it moves in the order of 16 to 64 kByte. Usually, the memory area for commands and data is separated from each other. The importance of the L1 cache increases with the higher CPU speed.

In the L1 cache, the most frequently used commands and data are buffered so that as few accesses as possible to the slow memory are required. This cache avoids delays in the data transfer and helps to optimally utilize the CPU.

L2 cache / second-level cache

In the L2 cache, the data of the working memory (RAM) is buffered.

The processor manufacturers supply the different market segments with specially modified processors via the size of the L2 cache. The choice between a processor with more clock speed or a larger L2 cache can be answered in a simplified manner as follows: With a higher clock, individual programs, especially with high arithmetic requirements, run faster. As soon as several programs run at the same time, a larger cache is an advantage. Typically, normal desktop computers with a processor that has a large cache are better served than with a processor that has a high clock rate.

When the memory controller was shifted from the chipset into the processor and the processor was able to access memory much faster, the importance of the L2 cache decreased. While the size of the L2 cache has decreased, the L3 cache has been properly upgraded.

L3 cache / third-level cache

As a rule, multicore processors use an integrated L3 cache. With the L3 cache, the Cache Koheranz protocol of Multicore processors can work much faster. This protocol compares the caches of all cores to maintain data consistency. The L3 cache thus has less functions of a cache, but is intended to simplify and speed up the cache coherency protocol and the data exchange between the cores.

As modern processors now contain several data cores - so-called cores - the manufacturers have already donated a third cache, the L3 cache, to these multi-core processors. All processor cores work together, which is particularly beneficial in parallel processing. This allows data shared by different CPU cores to be retrieved from the fast L3 cache. Without it, these data would always come from the slow main memory. In addition, the L3 cache also facilitates data management with multiple CPU cores and caches (data coherency).

Google Leak Reveals Pixel 2 'Shape Change'

Google Pixel 2: Code names indicate pixel successors and a new Nexus

Google, the internet giant is working on pixel 2. Now for the first time the codenames of the new Google smartphones have been revealed. So the pixel 2 internally to the name "Walleye" and the pixel XL 2 to the name "Muskie". A third device with the code name "Taimen" provides for speculation. Does Google plan a new Nexus smartphone?Will Google work on three new smartphones for the year 2017? According to media reports, the company is developing the Google Pixel and the Google Pixel XL as codename "Walleye" and "Muskie". "Walleye" is the smaller Google pixel 2, "Muskie" is the Pixel XL 2, reports the usually well-informed US blog Android Police. A reference to "Walleye" has already been discovered in the Android source code.
According to the web page "Droid Life", "Taimen" is said to be another new Google smartphone, which will show a larger screen than Pixel XL 2 to the informer of the website. Possibly, the display will measure six inches in the diagonal. According to Droid Life, "Taimen" is not likely to be marketed under the "Google Pixel" brand. So far the information here is very daring.

This is what the code names mean

What do the code names "Walleye", "Muskie" and "Taimen" mean? Traditionally, Google is designing new devices internally for fish and / or fish species, which was earlier in the Nexus smartphones. So the Nexus 6 was called "Shamu" because of its size. A homage to the killer whale from the SeaWorld shows.

The Nexus 5X was developed under the codename "Bullhead", the English term for catwels. The first pixel devices internally on Google called "Sailfish" (fanfish) and "Marlin" (spearfish). "Walleye" and "Muskie" are also fish species. "Walleye" is the English name for glass eye bass. Taimen, on the other hand, is a very large species of salmon.

Google Pixel 2 - Release, price and rumors

Google will unveil 2017 presumably successor for its pixel smartphones. In the net, first rumors circulate to a supposed Google pixel 2. The summarize of what Mono-live.com knew so far about the new Google smartphones.

In 2016 Google introduced its Nexus series and replaced the device family with the new product range Google Pixel. With the five-inch Google pixel and the 5.5-inch Google Pixel XL, the manufacturer launched two smartphones under the new name on the market. Both devices, however, did not differ from the size.

This year, Google will probably present successors for the pixel devices. In the following you will learn what Mono-live.com knew about the Google Pixel 2 and the Pixel XL 2.

Release: When will the new Google smartphones appear?

There is not yet a release date for Google Pixel 2 and Pixel XL 2. The first pixel smartphones appeared on 4 October 2016. It is therefore to be expected that Google will bring the successors in October 2017 on the market.

Price: How expensive are the new pixel smartphones

Also unclear is how expensive the new Google smartphones will be. Both the Google pixel and the pixel XL were anything but favorable. The prices began at 759 and 899 euros respectively. Currently there are rumors that Google will release a more affordable pixel model this year. However, this remains to be seen.

Harvard Scientists Use Simple Materials to Create Semi Soft Robots

Biologically Inspired Soft Robots

George Whitesides towards the start of the decade had assisted in rewriting the rules of what a machine could be with the improvement of biologically inspired soft robots and is now ready to rewrite it once again with the support of some plastic drinking straws. Whitesides together with Alex Nemiroski a former postdoctoral fellow in Harvard lab of Whitesides had been encouraged by arthropod insects and spiders and have developed a kind of semi-soft robot which is capable of standing and walking.

 The team has also developed a robotic water strider with the skill of pushing itself along the liquid surface. The robots have been defined in a recent paper published in the journal Soft Robotics. The new robots unlike the earlier generations of soft robots that could stand and walk uncomfortably by filling air chambers in their bodies are designed to be extremely quicker.

The researchers are expecting that the robots would finally be utilised in search operations, even though practical applications seems to be far away, in an event of natural calamities or in conflict zones. The Woodford L and Ann A. Flowers University Professor at Harvard, Whitesides stated that if one looks around the world, there are plenty of things like spiders and insects that are very agile.

Flexible Organisms on Planet

They can move rapidly, climb on various items and are capable of doing things which huge hard robot are unable to do due to their weight and form factor. They are among the most flexible organisms on the planet and the question was how we can build something like that.

The answer from Nemiroski was that it came in the form of one’s average drinking straw. He informed that it had all began from an observation which George had made that polypropylene tubes have an excellent strength-to-weight ratio. This gave rise to developing something which has more structural support than virtuously soft robots tend to have.

 That has been the building block and then they got inspiration from arthropods to figure out how to make a joint and how to use the tubes as an exoskeleton. After that there was a question of how far one’s imagination can go and once you have a Lego brick, what type of castle can one build with it. He added that what they built was a surprisingly simple joint.

Whitesides, with Nemiroski had started by cutting a notch in the straws enabling them to bend. The scientists then inserted short lengths of tubing which on inflation forced the joints to spread. A rubber tendon linked on either side then caused the joint to retract when the tubing flattened.

Microcontroller Run By Arduino

The team equipped with the simple concept, built a one-legged robot capable of crawling and moved up in intricacy as they added a second and later a third leg enabling the robot to stand on its own. Nemiroski stated that with every new level of system complexity they would have to go back to the original joint, making modifications in building it to be capable of exerting more force or to be capable of supporting the weight of larger robots.

Eventually when they graduated to six- or eight- legged arthrobots, enabling them to walk, became a challenge from the point of view of programming. For instance it was viewed at the way ants and spiders sequence the motion of their limbs and then attempted to figure out if the aspects of these motions were applicable to what they were doing or if the need for developing their own kind of walking tailored to these specific kinds of joints.

 Though Nemiroski together with his colleagues accomplished in directing simple robots by hand, by utilising syringes, they resorted to computers in controlling the sequencing of their limbs since the designs amplified by way of complexity. He informed that they had put together a microcontroller run by Arduino which tends to utilise valve together with a central compressor that enabled them the freedom to evolve their gait swiftly.

Motion of Joint – Binary – Simplicity of Valving System

Although Nemiroski along with his colleagues had been skilful in reproducing the distinctive `triangle’ gait of ants utilising their six-legged robot, imitating a spider-like gait, proved to be far riskier. He added that a spider has the tendency of modulating the speed which it extends and contracts its joints to carefully time which limbs are moving forward and backward at any point.

Nemiroski further added that however in our case, the motion of the joint is binary owing to the simplicity of our valving system. You either switch the valve to the pressure source to inflate the balloon in the joint and extend the limb or switch the valve to atmosphere in order to deflate the joint and thus retract the limb. In the case of the eight-legged robot, the gait compatible had to be developed with binary motion of the joints.

Though it was not a brand new gait but they could not accurately duplicate how a spider tends to move for this robot. Nemiroski stated that developing a scheme which can modify the swiftness of actuation of legs would be a useful objective for future exploration and would need programmable control over the flow rate supplied to each joint.

Academic Prototypes

Whitesides is of the belief that the techniques utilised in their development especially the use of daily off-the-shelf stuff can point the way toward future innovation, though it would take years before the robots make their way in the real world applications.

He stated that he does not see any reason to reinvent wheels and if one looks at drinking straws, they can make them all, effectively at zero cost together with great strength and so why not use them? They are academic prototypes and hence they tend to be very light weight though it would be quite easy to imagine building these with a lightweight operational polymer which could hold a considerable weight.

Nemiroski added that what is really attractive here is the simplicity and this is something George had been championing for some time and something which he grew to appreciate deeply while in his lab.

Flawed Fish Jaws Shed Light on Hearing Loss in Humans

Genetic Mutation – Malformation of Jaw

As per USC research in Scientific reports, the same genetic tweak which tends to cause malformed jaws in the case of fish could be responsible for some issues in hearing in humans which seems to have some evolutionary origins. Scientists are of the belief that the arrangements which seem to support the jaws of primeval ancestral fish gave rise to three tiny bones towards the middle ear of humans as well as other mammals which transmit sound vibrations where the bones are known as malleus, incus and stapes.

 In zebra fish, a genetic mutation could result in malformation of the jaw and hence USC researchers speculated if an equivalent genetic change could activate hearing defects in mice and humans. To comprehend the query, Camilla Teng, USC PhD student coordinated along with the other colleagues in the USC Stem Cell laboratories of Gage Crump, Rob Maxson, and Neil Segil and with clinical experts in radiology, audiology and genetics at the Keck School of Medicine of USC and Children’s Hospital Los Angeles.

They researched on two genes JAG1 and NOTCH2 which were mutated in most patients with Alagille syndrome - AGS which a genetic condition causing several symptoms in various parts of the body inclusive of the liver.

Hearing Loss – Deficits in Sensory Cells of Inner Ear

A person with Alagille syndrome tends to have less than normal number or small bile ducts in the liver which is the organ in the abdomen between the chest and hips that makes blood proteins, bile storing energy and nutrients, combats infection as well as eliminates harmful chemicals from the blood.At least in half of the patients, the syndrome tends to affect hearing loss besides liver, eye, heart and skeletal defects.

Though some of this could be hearing loss due to deficits in the sensory cells of the inner ear, the researchers have been speculating on the conductive hearing loss that involves essential components of the middle ear like the vibrating bones.

With the introduction of mutations in mice, the researchers observed flaws in the incus as well as the stapes bones together with corresponding hearing loss. Thereafter they attended Alagille Alliance meetings in 2011 and 2014 performing hearing tests later on 44 human patients affected with Alagille syndrome to determine if their hearing loss had been conductive, sensor in neural or mixed.

Conductive Hearing Loss

As predicted by their discoveries in zebra-fish and mice, they observed conductive hearing loss had been the most common type which had affected almost one third of all ears. The CT scans of 5 AGS patients showed a more considerable complex picture, an unexpected variety of basi cflaws in the middle ear having variable effects on hearing.

One out of the five patients had a stapes flaw precisely related with conductive hearing loss.Teng commented that their study emphasized a generally unnoticed phenotype of Alagille Syndromes.

According to Teng, the study provided some insight on generally overlooked issue arising among individuals with Alagille syndrome. She stated that if patients tend to be conscious of possible conductive hearing loss earlier in life, they can seek medical aidin time for abetter quality of life.

Peering Into Fish Brains to See How They Work

Transparent Fish – Work in the Dark

The main focus in the research of the latest group at the Kavli Institute for Systems Neuroscience is transparent fish and the capability to work in the dark. One of the important challenges faced by neuroscientists wanting to comprehend how the brain works is essentially reckoning out how the brain is wired together and how neurons tend to interact.

NTNU neuroscientists and Nobel laureates May-Britt and Edvard Moser resolved this issue by studying how to record from individual neurons in the rat brain when the rats tend to move freely in space. They utilised the recording in order to make the findings that had attained them the Nobel Prize.

They were in a position to understand that certain neurons in the entorhinal cortex fired in a manner that created a grid pattern which could be utilised in navigating like an internal GPS. Emre Yaksi, the latest teamhead of the Kavli Institute for Systems Neuroscience utilised a diverse approach to the issue of viewing what tends to go on within the brain.

Rather than studying rats or mice, Yakshi resorted to around 90 various types of genetically modified zebra-fish which he could breed in creating various fish with preferredphysiognomies.

Comprehending Universal Circuit Architectures in Brain

Young larval zebra-fish are said to be totally transparent and hence Yakshi needed only a systematic optical microscope to view what tends to occur inside their heads. Some of the fishes of Yakshi seem to have a genetic modification which makes their neurons light up while they direct signal to another neuron and he has informed that this is what tends to make circuits and connections visible to researchers.

He commented that they are interested in comprehending the universal circuit architectures in the brain which can perform interesting computation. Though fish are quite different from humans, their brains tend to have identical structures and in the end fish also have to find food, they also have to find a mate, they have to avoid dangers and they build brain circuits which can generate all these behaviours just the way humans tend to do.

When Yaksi had come to Kavli Institute in early 2015 together with a team of researchers they had a 900 kg anti-vibration table which was the size of a billiards table. The table had been big and heavy and was needed in the laboratory to reduce vibration when they had to use the highly sensitive optical microscopes to peer into the brains of the zebra-fish.

Zebra-Fish Genetically Adapted

The larval fish tend to be quite small that a slight vibration from cars or trucks passing by the streets could make the microscopes bounce away from their miniature brain targets. Zebra-fish brains are quite small, around 10,000 to 20,000 neurons which is a figure dwarfed by the human brain that tends to have an estimated neurons of 80 billion.

However the measurement that Yaksi together with his colleagues tend to make marks in huge quantities of data. According to him, a 30 minute of recording could generate data which tends to take about a week to process the same. It was for this purpose, the research group of Yaksiis a multi-disciplinary team of engineers, physicists and life scientists who seemed to be trained to develop and utilise computational tools in analysing these huge datasets.

Since few of the zebra-fish tend to be genetically adapted in order that their neurons light up with a fluorescent protein when the neurons are active, Yaksi and his colleagues tend to work frequently in low light or darkness. This is particularly obvious when he takes visitors in the subdued darkness of the laboratory where several of the fanciest microscopes are confined in boxes open towards the front, developed to restrict the amount of external light.

Research – Causes of Seizures/How Seizures Prevented

Yaksi had informed that other zebra-fish are genetically modified to shine a blue light in their brain which tends to activate certain neurons enabling the researchers to plan connections between neuron. Major part of the study being done by the group of Yaksiis basic research with findings which tend to improve our understanding of the brain computation though does not specifically have any instant clinical implications.

However, Nathalie Jurisch-Yaksi, wife and colleague of Yaksi is working with medical doctors in order to develop genetically modified zebra-fish which could be helpful in shedding light on brain disease like epilepsy.According to Yaksi, most of the people in his lab are doing basis research attempting to ask how does the brain works, how is it connected, how is it built.

 Nonetheless, Nathalie is working at NTNU with medical doctors and they are trying to reach out to clinicians. For instance he stated that if a brain disorder like epilepsy tends to have a genetic component, that same genetic mutation could be developed in the transgenic group of zebra-fish facility in order that the team could research on the causes of seizures in a diseased brain and how the seizures can be prevented.

Kavli Institute – Excellent Science Environment

The Kavli Institute had been on an institute-wider retreat, when he had come to Trondheim for interview for the position, so Yaksi had the opportunity of meeting not just group leaders but also technicians, master’s students, PhD candidates and everyone. He informed that what was most impressive besides the excellent science environment was that people had been happy and satisfied with what was being done and it was a good atmosphere.

 Though the science had been the most serious part of his decision to move to Trondheim, he informed that he was excited to be a part of the Kavli Institute since he and his wife desired to live in a smaller town as well as close to nature.

He had stated that Trondheim seems to be a unique place and one can do really good science and yet be close to nature, which was a big thing for him and his wife. Going to London or another big city was never an option and they did not desire to deal with big city life. He also informed that when May-Britt Moser had asked him at the time of his interview on what he knew regarding Scandinavia. His reply had been that he did not know much though he had added that he and his wife loved being outdoors.