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What does it mean when it says cache has a write-through policy and write-back policy?
Wiki User
∙ 15y ago
write through policy is whereby the cache and the main memory locations are updated simultaneously. As for write back policy,the main memory is updated much later when the block cöntaining the words is being removed frm the cache
Wiki User
∙ 15y ago
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What type of memory is mostly closely connected to the CPU?
In this instance, you likely mean cache memory, though you could mean RAM, particularly DRAM. Cache memory, like the L1, L2, and L3 processor cache, helps to speed up operations between the CPU and RAM.
What is reducing cache misses?
Cache memory is fast memory that resides immediately next to the CPU; it is virtually 15 times faster than the next fastest memory: system RAM. The system RAM is organised from "location 0" to "location n" where "n" is the number of bytes your computer has of RAM. The Cache is like yellow stickers on your desk, with the location slot on top. So this memory is accessed according to content not to where it is.So cache memory is very limited-- usually less than 4 MB-- compared to system RAM, which may have many gigabytes. That being said, the CPU tries to predict which system memory it will need next, and instructs the address control unit to prefetch this data and place it into the cache. If the CPU was correct in "guessing" the memory blocks the CPU can blaze along with its processing at the 2ns speed typically found in cache memory. This is a cache hit. However, if the CPU incorrect in its educated guess, then it must request the memory content from the RAM memory and wait up to 15 times longer, somewhere in the neighborhood of 60ns. This is referred to a "cache miss.". This "copy" is kept in the cache, and should the CPU modify this, it will modify the cache content only, and leave it to the cache to update the RAM - "write-through". Cache misses are undesirable, while cache hits are highly desirable; a system that missed 100% of the time would literally run more than 15 times slower than a cache that hit 100% of the time. A cache miss actually increases the processing time above what it would have been without any cache at all because of the extra memory it has to request. Reduction of cache misses is done by changing the microcode that the CPU uses to "guess" which memory it will need next. These are very sophisticated algorithms that have remained the same for decades. Guessing the next instruction is simple, it is usually the next and for a condition, you can pre-fetch for both results. Data is based on "what you have used lately will be used again". You now have to consider the complexity of the cache memory - this is accessed by content "location"/"address" and return the content. The more you have to search, the slower will the cache be. The one that write the code can make a huge change. Simply by not use data that is all over the place, but a small set, and reuse this. The other is to minimize "context switches" - execute as much as possible without having to wait for the entire cache to be cleared. Writing code in VBA will be encoded as it is executed, which is a huge overhead compared to defining simple sequences that gets things done. The basics is the same today as those that P.J. Denning and D. Coffman described in "Operating System Theory" in 1978, when they introduced the notion of "Working Set". They describe the reason for why "more" does not always mean "better performance".
What does group policy mean in computer language?
Group Policy is a feature of the Microsoft Windows NT family of operating systems. Group Policy is a set of rules which control the working environment of user accounts and computer accounts. Group Policy provides the centralized management and configuration of operating systems, applications and users' settings in an Active Directory environment. In other words, Group Policy in part controls what users can and can't do on a computer system. Although Group Policy is more often seen in use in enterprise environments, it is also common in schools, smaller businesses and other kinds of smaller organizations. Group Policy is often used to restrict certain actions that may pose potential security risks, for example: to block access to the Task Manager, restrict access to certain folders, disable the downloading of executable files and so on.OverviewGroup Policy can control a target object's registry, NTFS security, audit and security policy, software installation, logon- and logoff-scripts, Security filtering is the process of customizing the scope of the GPO by choosing which users and groups the GPO applies to.Windows Management Instrumentation (WMI) filtering is the process of customizing the scope of the GPO by choosing a WMI filter to apply.Delegation is the process of customizing the security descriptors of the GPO by assigning specific users and groups and the individual permissions that will be applied for each. This has more control than security filtering as it allows modification of both Apply and Deny permissions.[edit] GPO applicationThe Group Policy client operates on a "pull" model - every so often (a randomized delay of between 90 and 120 minutes, although this offset is configurable via Group Policy) it will collect the list of GPOs appropriate to the machine and logged on user (if any). The Group Policy client will then apply those GPOs which will thereafter affect the behavior of policy-enabled operating system components and applications.[edit] Local Group PolicyLocal Group Policy (LGP) is a more basic version of the Group Policy used by Active Directory. In versions of Windows before Windows Vista, LGP can configure the Group Policy for a single local computer, but unlike Active Directory Group Policy, can not make policies for individual users or groups. It also has many fewer options overall than Active Directory Group Policy. The specific-user limitation can be overcome by using the Registry Editor to make changes under the HKCU or HKU keys. LGP simply makes registry changes under the HKLM key, thus affecting all users. The same changes can be made under HKCU or HKU to only affect certain users. Microsoft has more information on using the Registry Editor to configure Group Policy available on TechNet.[1] LGP can be used on a computer on a domain, and it can be used on Windows XP Home Edition.Windows Vista supports Multiple Local Group Policy objects (MLGPO), which allows setting local Group Policy for individual users.[2][edit] SecurityOne potential problem with per-user policies is that they're only enforced voluntarily by the targeted applications. A malevolent user can interfere with the application so that it cannot successfully read its Group Policy settings thus enforcing potentially lower security defaults or even return arbitrary values.[citation needed] The user can also create a copy of the application at a writable location, then modify it such that it ignores the Group Policy settings.[citation needed][edit] See alsoGroup Policy improvements in Windows VistaAdministrative Templates[edit] References[3]^ Group Policy Settings Reference^ Step-by-Step Guide to Managing Multiple Local Group Policy Objects^ Remote installation without using Group Policy[edit] External linksMicrosoft Group Policy pagehttp://www.gpanswers.com/The Group Policy Management Console (GPMC)Step-by-Step Guide to Managing Multiple Local Group Policy ObjectsGroup Policy Settings (in Excel format) and registry key equivalents, from Microsoft[hide] v • d • e Windows componentsCore Aero · AutoRun · ClearType · Desktop Window Manager · DirectX · Explorer · Taskbar · Start menu · Shell (Shell extensions ·namespace · Special Folders · File associations) · Search (Saved search · IFilter) · Graphics Device Interface · Imaging Format · .NET Framework · Server Message Block · XML Paper Specification · Active Scripting (WSH · VBScript · JScript) · COM (OLE · OLE Automation · DCOM ·ActiveX · ActiveX Document · Structured storage · Transaction Server) · Previous Versions ·Win32 consoleManagementtools Backup and Restore Center · command.com ·cmd.exe · Control Panel (Applets) · Device Manager · Disk Cleanup · Disk Defragmenter · Driver Verifier · Event Viewer · Management Console ·Netsh · Problem Reports and Solutions · Sysprep · System Policy Editor · System Configuration · Task Manager · System File Checker · System Restore · WMI · Windows Installer · PowerShell · Windows Update · WAIK · WinSAT ·Windows Easy TransferApplications Calculator · Calendar · Character Map · Contacts · DVD Maker · Fax and Scan ·Internet Explorer · Journal · Mail · Magnifier · Media Center · Media Player · Meeting Space · Mobile Device Center · Mobility Center ·Movie Maker · Narrator · Notepad · Paint · Photo Gallery · Private Character Editor ·Remote Assistance · Windows Desktop Gadgets ·Snipping Tool · Sound Recorder · Speech Recognition · WordPadGames Chess Titans · FreeCell · Hearts · Hold 'Em · InkBall · Mahjong Titans · Minesweeper · Purble Place · Solitaire · Spider Solitaire · TinkerKernel Ntoskrnl.exe · hal.dll · System Idle Process · Svchost.exe · Registry · Windows service · Service Control Manager · DLL · EXE ·NTLDR / Boot Manager · Winlogon · Recovery Console · I/O · WinRE · WinPE · Kernel Patch ProtectionServices BITS · Task Scheduler · Wireless Zero Configuration · Shadow Copy · Error Reporting · Multimedia Class Scheduler · CLFSFile systems NTFS (Hard link · Junction point · Mount Point · Reparse point · Symbolic link · TxF · EFS) · FAT32·FAT16·FAT12 · exFAT ·CDFS · UDF · DFS · IFSServer Domains · Active Directory · DNS ·Group Policy · Roaming user profiles · Folder redirection · Distributed Transaction Coordinator ·MSMQ · Windows Media Services · Rights Management Services · IIS · Terminal Services · WSUS · Windows SharePoint Services · Network Access Protection · PWS · DFS Replication · Remote Differential Compression · Print Services for UNIX ·Remote Installation Services · Windows Deployment Services · System Resource Manager · Hyper-VArchitecture NT series architecture · Object Manager · Startup process (Vista) · I/O request packet · Kernel Transaction Manager · Logical Disk Manager · Security Accounts Manager · Windows Resource Protection · LSASS · CSRSS · SMSS ·MinWinSecurity User Account Control · BitLocker · Defender · Data Execution Prevention · Security Essentials · Protected Media Path · Mandatory Integrity Control · User Interface Privilege Isolation · Windows Firewall · Security CenterCompatibility Unix subsystem (Microsoft POSIX · Interix) · Virtual DOS machine · Windows on Windows ·WoW64 · Windows XP Mod
Mean by first impression last?
whats mean of first impression whats mean of first impression
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cache = hide capacité = capacity
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What does le cache mean?
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What does cashe bdm mean?
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