An Overview of Cache Principles
نویسنده
چکیده
Cache So, we can never reach a Final Understanding of anything because it will change as we develop understanding. If we did reach a Final Understanding, simultaneously the " subject " would have changed, rendering our understanding as past tense …. A cache (also called " look-aside " [Bloom et al. 1962] or " slave memory " [Wilkes 1965]) can speed up accesses to all manners of storage devices, including tape drives, disk drives, main memory, servers on the network (e.g., web servers are a type of storage device), and even other caches. It works on the principle of locality of reference, the tendency of applications to reference a predictably small amount of data within a given window of time [Belady 1966, Denning 1970]. Any storage device can be characterized by its access time and cost per bit, where faster storage technologies tend to have a lower access time and cost more per bit than slower technologies. A cache fronting a given storage device would be built from a technology that is faster than that of the storage device in question; the cache technology would typically cost more on a per-bit basis, but to be effective the cache would only need to be large enough to hold the application's working set—the set of instructions and/or data items the application is currently using to perform its computations [Denning 1967]. Due to locality of reference, most of the application accesses will be satisfi ed out of the cache, and so most of the time the access characteristics will be that of the cache: far faster and often consuming less energy than the larger storage device behind the cache. As far as implementation technologies, caches can be built of anything that holds state. Hardware caches are used widely in computer systems (SRAM can act as a cache for DRAM; DRAM can act as a cache for disk; fast DRAM can act as a cache for slow DRAM; disk can act as a cache for tape; etc.), and software caches abound as well (the operating system caches disk blocks and network addresses; web proxies cache popular web-based documents; even hardware devices such as disk drives cache data locally, implementing the cache algorithm in software executing on a control processor). In addition, what is logically a single cache may, in fact, be comprised of many distinct entities that operate in concert. For instance, the separate …
منابع مشابه
Reduction in Cache Memory Power Consumption based on Replacement Quantity
Today power consumption is considered to be one of the important issues. Therefore, its reduction plays a considerable role in developing systems. Previous studies have shown that approximately 50% of total power consumption is used in cache memories. There is a direct relationship between power consumption and replacement quantity made in cache. The less the number of replacements is, the less...
متن کاملReduction in Cache Memory Power Consumption based on Replacement Quantity
Today power consumption is considered to be one of the important issues. Therefore, its reduction plays a considerable role in developing systems. Previous studies have shown that approximately 50% of total power consumption is used in cache memories. There is a direct relationship between power consumption and replacement quantity made in cache. The less the number of replacements is, the less...
متن کاملAnalysis and Design of Hierarchical Web Caching Systems
This paper aims at finding fundamental design principles for hierarchical web caching. An analytical modeling technique is developed to characterize an uncooperative two-level hierarchical caching system where the least recently used (LRU) algorithm is locally run at each cache. With this modeling technique, we are able to identify a characteristic time for each cache, which plays a fundamental...
متن کاملAn Overview of Challenges in Producing and Consuming Transgenic Products
The production and consumption of genetically modified (GM) products are highly controversial due to their environmental, health, and ethical impacts. Most of these disputes are caused by distrust of regulatory authorities, scientists, and technocratic decisions. Among all these concerns, health issues, allergenicity and antibiotic resistance are more important. Many of today's social developme...
متن کاملHierarchical Web caching systems: modeling, design and experimental results
This paper aims at finding fundamental design principles for hierarchical web caching. An analytical modeling technique is developed to characterize an uncooperative twolevel hierarchical caching system where the least recently used (LRU) algorithm is locally run at each cache. With this modeling technique, we are able to identify a characteristic time for each cache, which plays a fundamental ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2007