Cach Memory For Computers-www.7808.cn

Computers-and-Technology The second major component in any computer is the memory. Ideally, a memory should be extremely fast (faster than executing an instruction so the CPU is not held up by the memory), abundantly large, and cheap. Current technology is not developed to satisfy these requirements. The memory system is constructed as a hierarchy of layers. The top layer consists of the registers internal to the CPU. They are made up of the same material as the CPU and are as fast as the CPU. Consequently, there is no delay in accessing them. The storage capacity available in them is typically according to the number of bits present. Programs must manage the registers. The cache memory is mostly controlled by the hardware. Main memory is divided up into cache lines, typically 64 bytes, with addresses 0 to 63 in cache line 0, addresses 64 to 127 in cache line 1, and so on. The most heavily used cache lines are kept in a high-speed cache located inside or very close to the CPU. When the program needs to read a memory word, the cache hardware checks to see if the line needed is in the cache. If it is, called a cache hit, the requested is satisfied from the cache and no memory request is sent over the bus to the main memory. Cache hits normally take about two clock cycles. Cache misses have to go to memory, with a substantial time lag. Cache memory is limited in size due to its high cost. Some machines have two or even three levels of cache, each one slower and bigger than the one before it. Main memory comes next. This is the workhorse of the memory system. Main memory is often called RAM (Random Access Memory). Currently, memories are tens to hundreds of megabytes and growing rapidly. All CPU requests that cannot be satisfied out of the cache go to main memory. In addition to the kinds of memory discussed above, many computers have a small amount of nonvolatile random access memory. Unlike RAM, nonvolatile memory does not lose its contents when the power is switched off. ROM is programmed at the factory and cannot be charged afterward. It is fast and inexpensive. On some computers, the bootstrap loader used to start the computer is contained in ROM. Also, some Input and output cards come with ROM for handling low-level device control. About the Author: By: Neal David – For many people who are conscious about staying healthy and fit various fitness devices hold a lot of appeal. Managing your fitness regime becomes very easy when you have such gears at your aid. One such gear is the Bluetooth watch bracelet. By: Aaron – Some honest to goodness organizations offer you a guarantee period of the services they have offered. They have confidence in the nature of the work they convey. You can consider such offices after some ground research has been finished. Verify that you are getting your computer … By: Neal David – The literal meaning of the word "mobile" is to a certain extent lost due to the wired chargers which kind of limits the freedom of consumers to use their mobile handsets in a more optimal manner. By: smartweb – Homeowners Association(HOA) is an American corporation established by the real estate world for the purpose of marketing, managing, selling and buying ofproperties. By: Neal David – Note 5 screen protector from MXx has gained a lot of popularity, but, before you decide to buy one for yourself, why not examine its features closely? Yes, this screen protector has been found an advantageous purchase by many and that is for obvious reasons. By: Neal David – Smart phones are very essential part of our lives. It is not just a phone but a gadget with multiple utilities and to get the best of all worlds we love to spend as much as we can to get the best one. By: jaspreet sason – Software is very user-friendly. Software is not only used in computers. These are used in so many devices such as in washing machine, robots, microwaves, satellites, mobiles, video games etc. Even a normal person who is using a mobile is operating software By: Neal David – Many enthusiast travelers and other mobile hand set users (almost the entire population, obviously) would have faced a situation sometime in their lives when they are out on a long journey or a drive with a fully loaded mobile handset, which in turn runs out of charge after a cou … By: Neal David – It is often claimed by experienced users that any metric which cannot be quantified cannot be tracked and monitored. This is one of the most relevant problems in fitness schedules and work outs where in the person is unaware of the quantifiable measures of his work out routing. By: Mark Wadsen – As the name of the website suggests, these guys are interested in finding only those pieces that will make your computer better than ever. So instead of losing precious time trying to figure out what are the best components and accessories for your PC, access this website, as all … 相关的主题文章:

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