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重複資料刪除是一種從資料底層中釜底抽薪節省儲存空間的新技術，藉由區塊等級的分析比對，可找出並刪除整個儲存區域中的冗餘資料，讓有限空間發揮出遠超過實體容量的儲存效益。 文/ 張明德 | 2007-09-07 發表 找出並去除資料中的冗餘 重複資料刪除是一種從資料底層中釜底抽薪的儲存擴充新做法。從檔案的層級看資料，檔案名稱和內容均相同，才能算是重複。用區塊的方式分析資料，將有許多機會找出相同的排列方式，例如具備跨多個檔案比對的能力，並且能從更精細的層級縮減，並非只是檔案壓縮。 重複資料刪除技術的特性 重複資料刪除技術分析資料的方式，由於考慮到資料量的龐大，在實務上通常都是把資料以區塊或區段為單位，並透過Hash函數（或類似函數）的演算，讓系統來執行資料分析與比對的工作。 重複資料刪除技術的類型 依處理流程、運作架構以及對原始資料進行分段方式的不同，重複資料刪除技術有以下幾種不同的區分：從架構上來看，重複資料刪除技術可分在來源端或在目標端執行刪除演算；線上即時處理，或是寫入磁碟後再行處理等。 重複資料刪除產品類型 目前的De-Dupe產品由於架構與技術上的差異，在應用環境、銷售方式與針對客戶群方面也有所不同。依產品類型可分備份軟體、VTL與儲存伺服器等三大類。 重複資料刪除技術能節省多少空間？ 所有重複資料刪除技術的供應商，都宣稱他們產品能達到極高的資料刪減比率，保守的講法為20：1～50：1，較聳動的講法則甚至有300：1、500：1等驚人的數字。因此在透過實際測試驗證各產品的資料刪減比率前，有必要先釐清資料刪減比率的涵義。 ------------------------------------------------------------------------------------- 五款De-Dupe產品實測 我們這次一共測試了五款應用了De-Dupe技術的產品，分別為Data Domain DD410、EMC Avamar、Falconstor SIR、NetApp A-SIS與Symantec Pure Disk。 >>>測試方式 Data Domain DD410 DD410是Data Domain儲存伺服器系列中的入門產品，具備儲存容...

CPU Basics: Multiple CPUs, Cores, and Hyper-Threading Explained by Chris Hoffman on June 15th, 2017 The central processing unit (CPU) in your computer does the computational work—running programs, basically. But modern CPUs offer features like multiple cores and hyper-threading. Some PCs even use multiple CPUs. We’re here to help sort it all out. RELATED: Why You Can’t Use CPU Clock Speed to Compare Computer Performance The clock speed for a CPU used to be enough when comparing performance. Things aren’t so simple anymore. A CPU that offers multiple cores or hyper-threading may perform significantly better than a single-core CPU of the same speed that doesn’t feature hyper-threading. And PCs with multiple CPUs can have an even bigger advantage. All of these features are designed to allow PCs to more easily run multiple processes at the same time—increasing your performance when multitasking or under the demands of powerful apps like video encoders and modern games. So...

What Is UEFI, and How Is It Different from BIOS? by Chris Hoffman on November 27th, 2017 The BIOS will soon be dead: Intel has announced plans to completely replace it with UEFI on all their chipsets by 2020. But what is UEFI, and how is it different from the BIOS we’re all familiar with? Both UEFI and BIOS are low-level software that starts when you boot your PC before booting your operating system, but UEFI is a more modern solution, supporting larger hard drives, faster boot times, more security features, and—conveniently—graphics and mouse cursors. We’ve seen newer PCs that ship with UEFI still refer to it as the “BIOS” to avoid confusing people who are used to a traditional PC BIOS. Even if your PC uses the term “BIOS”, modern PCs you buy today almost certainly ship with UEFI firmware instead of a BIOS. Here’s why. What Is a BIOS? RELATED: What Does a PC’s BIOS Do, and When Should I Use It? BIOS is short for Basic Input-Output system . It’s low-level s...