BACKGROUND Erasable memories may have erasable elements that can become unreliable after a predetermined number of erase cycles. Thus, if one cell is erased dramatically more than other cells, that cell may be prone to earlier failure than the rest o…
BACKGROUND OF THE INVENTION Solid-state memory devices encompass rewritable non-volatile memory devices which may use electronic circuitry for storing data. Currently, solid-state memory devices start replacing conventional storage devices such as ha…
Techniques are presented that include determining, for data to be written to a nonvolatile memory, a location in the nonvolatile memory to which the data should be written based at least on one or more wear metrics corresponding to the location. The…
很好的一道题呀 思路 状态\(d(i,j)\)表示已经经过了行程单中的\(i\)个城市,目前在城市\(j\)的最小代价,直接建边跑最短路就行了 比如机票为\(ACBD\),行程单为\(CD\),那么对于\((0,A)\),连向\((1,C)\),\((1,B)\),\((2,D)\) 有两个需要注意的地方 1.起点为\((1,行程单的起点)\) 2.城市编号很大,要离散化 以下是代码,离散化用\(map\)完成 #include <algorithm> #include <iostrea…
No one knows exactly why some babies are born prematurely(早产), but some of the smallest premature babies weigh under 1,500 grams. These tiny babies -- called micro preemies -- can't afford to lose an ounce. At Children's National Medical Center in Wa…
前面说过,闪存寿命是以P/E次数来计算的,而WL就是确保闪存内每个块被写入的次数相等的一种机制.若没有这个机制,SSD内的闪存颗粒就无法在同一时间内挂掉,那对用户来说就是灾难.       会出现这种情况的原因在于,用户在LBA空间里的数据更新速度是不同的,有部分是经常需要更新,而有些却长期不需要变更,因此若没有WL,很显然那些经常被更新的数据所在的闪存寿命会首先被消耗完毕,而不怎么需要变更的数据所在的闪存损耗就要小得多.为了避免出现这种状况,便需要WL这个机制来保持SSD内的每个闪存颗粒的磨损…
SRC=http://www.cs.rutgers.edu/~pxk/416/notes/13-fs-studies.html Paul Krzyzanowski April 24, 2014 Introduction We've studied various approaches to file system design. Now we'll look at some real file systems to explore the approaches that were taken i…
词条积累 1.NAND flash memory http://www.searchstorage.com.cn/whatis/word_6052.htm http://baike.baidu.com/subview/64506/5136742.htm?fromtitle=NAND%E9%97%AA%E5%AD%98&fromid=8051173&type=syn 2.FTL http://hi.baidu.com/alan_ding/item/7895367e324d5e3ed7a89c…
SDD 基础知识 SSD(Solid State Drives)是固态硬盘,使用闪存颗粒来存储数据,闪存又可分为NAND Flash和NOR Flash,通常所说的SSD硬盘都使用NAND Flash芯片来存放数据.NOR型存储内容以编码为主,其功能多与运算相关:NAND型主要功能是存储资料. Nor Flash:主要用来执行片上程序 优点:具有很好的读写性能和随机访问性能,因此它先得到广泛的应用: 缺点:单片容量较小且写入速度较慢,决定了其应用范围较窄. NAND Flash:主要用在大容量存…
======================================================================= SSD 特性 .随机读能力非常好,连续读性能一般,但比普通 SAS 磁盘好: .不存在磁盘寻道的延迟时间,随机写和连续写的响应延迟差异不大. .erase-before-write 特性,造成写入放大,影响写入的性能: .写磨损特性,采用 Wear Leveling 算法延长寿命,但同时会影响读的性能: .读和写的 I/O 响应延迟不对等(读要大大好于写…