how to defragment

is called by the garbage collector when the object is destroyed, and by overriding the Finalize () method, you can defragment the system resources or perform other cleanup work. and Both and can be used as the logical AND operator, representing logic and (and), when the result of an expression on either side of the operator is true, the entire result is true, otherwise the result is false if one of the parties is false. also has a short-circuit fu

considered nodes that are not referenced, that is, useless nodes.Red is a useless node and can be recycled.Currently, the objects in Java that can be used as GC root are:1. Objects referenced in the virtual machine stack (local variable table)2. Objects referenced by static properties in the method area3. Objects that are normally referenced in the method area4. Objects referenced in the local method stack (native objects)Basic all GC algorithms refer to the concept of root search algorithm.2.

-xx:cmsinitiatingoccupancyfraction), it is necessary to carry out fully GC, If the user thread consumes memory that is not particularly large, you can properly raise the-xx:cmsinitiatingoccupancyfraction to reduce the number of GC times and improve performance, if the reserved user thread memory is not enough, it will trigger concurrent Mode Failure, At this point, the fallback scenario will be triggered: collect using the serial old collector, but the pause time is long, so the-xx:cmsinitiating

new generated total space of about 176MB, using 91MB, "in parentheses should be the de facto memory address, memory address used, end memory address"Eden Space Young generation about 152MB, has used 52% "3 addresses using 16 binary subtraction calculation, about 80M, spare 72MB"The From space is approximately 20MB, using 43%.To space is about 20MB, using 0%Tenured generation about 192MB, the use of about 92MB, accounted for 47%, assuming this area is full, then will trigger the full amount of g

performance.10. Online defragmentation. Although delayed allocations, multiple allocations, and extents can effectively reduce file system fragmentation, fragmentation is unavoidable. EXT4 supports online defragmentation and will provide e4defrag tools to defragment individual files or the entire file system.The inode-related characteristics. The EXT4 supports larger inode sizes, compared to the default inode size of Ext3 of 128 bytes, EXT4 in order

that some empty position in the track is not able to store the next file in a row, generally this is scattered stored in different tracks, when reading this part of the data, the disk pointer to go back and forth a few laps, Cause performance degradation, which is the origin of file fragmentation. So it is necessary to defragment at intervals. But now some new hard drives, such as SSDs, have no tracks, so they don't need to be defragmented like tradi

including Java,. NET, Python, Perl, REST, and several other languages such as Ruby. For other languages, the need to access their web Service,gsoap through the SOAP protocol is a common suite for writing Web service client programs in the C + + language.For more information, please read https://www.vmware.com/support/pubs/sdk_pubs.html1.3.2 VDDK and VADPThe VDDK full name is Virtual Disk Development Kit, which helps developers create applications that access virtual machine storage. VDDK is bas

data, that is, the number of data block (block), if there are 1,3,5,7 four numbers to store content, the operating system can be arranged according to the reading order of the disk, can be a breath of four Block content read out , which is like a parallelization process. However, the FAT file system does not exist in this format, so fat has no way to read all blocks of this file from the beginning. Assuming that the file's data is written sequentially to the 1->3->5->7 number four block numbers

3 (Kernel 2.4) There seems to be no good way, one is to use the Hugemem kernel (God knows will not introduce new problems), one is to upgrade to 2.4.21-47 and use the new core parameters Vm.vm-defragment control the number of fragments. And then use RHEL 4 (Kernel 2.6), which goes back. Plainly, if you encounter an OOM Killer, basically the lower version of Kernel is somewhat flawed in design.Other, if go to query RedHat Bug Library, will find many K

#安装目标: Use XP to store the remaining space to install Ubuntu and form a dual system. Defragment the disk space you want to install #需要无损磁盘工具, with the "AO Mei Division assistant", lazy did not choose other tall English software. XP hard disk partition for cdef+ mobile hard disk I, E disk has 10G of space, F disk has 3G Adjust the size of the e-drive to cut out a 8G unused space, and F to cut out 2G. The

1, basically the main Linux file system for EXT2, the file system information is mainly:(1) Superblock: Record The overall information of this file system, including the total amount of inode/block, the amount of usage, the amount of surplus, and the format and related information of the file system.(2) Inode: Record the attributes of a file, a file occupies an inode, while recording the block number of this file's data.(3) Block: The contents of the actual record file, if the file is too large,

Garbage collection Algorithm https://www.cnblogs.com/jilodream/p/9038853.htmlWhen it comes to Java, the GC must not be bypassed, although it is not a Java initiative, but Java must be represented by GC. GC is garbage collection, more directly, is memory recycling. is to defragment the memory so that the memory is reused as large as possible. Always want to write a good article about GC, but found to write something too big, not a blog can be simply in

(horizontal Division, vertical division) 4, read and write "update, delete, add" separation 5, the storage process "modular programming, can improve speed" 6, configure the MySQL configuration optimization "Configure maximum concurrency number My.ini, adjust the cache size" 7. mysql Server hardware upgrade 8, regular to remove unnecessary data, scheduled to defragment (MyISAM) Why does the field use NOT NULL as much as possible instead of NULL? In M

system are represented by the identification value;19. Using Optimize tablefor frequently modified tables, it is easy to fragment, making it necessary to read more disk blocks when querying the database and to reduce query performance. A disk fragmentation problem exists with variable-length tables, which are more prominent for BLOB data types because their size varies greatly. You can defragment the data by using optimize table to ensure that databa

disk read head will not be able to read all the data on the disk, so the disk will be more than a few laps to complete the contents of this file! Do you often hear the so-called "defragmentation"? The reason for defragmentation is that the block of file writes is too discrete, and the performance of the file reads becomes poor. This time can be through the defragmentation of the same file belongs to the blocks together, so that the data will be easier to read! Assuming that the FAT file system

Computer shutdown Slow Reason there are two: one is the hardware configuration is not good, the other is the system does not do a good job optimization settings! Today, the small part of the system is going to tell you how to speed up system shutdown through system optimization settings. 1, Start-> Control Panel-> Power Options-> enable advanced power management. 2, look at the computer Device Manager to see if there is a driver problem with the hardware equipment, if so, reinstall the relevan

visual effects Anyway, Win8 's interface theme has been reversed, and the aero matte effect has been canceled, so we don't care about the visual effects. Off Method: System Properties – Advanced – Performance – settings – turns off fade in effect. Then open the folder, small software and so on, speed-leveraging! 2. Turn off disk defragmentation (optimize drive) schedule Disk defragmentation can improve disk performance, but if you are accustomed to manual collation, you can turn off the fini

press the "D" (delete), XP will confirm, because of fear you delete the wrong, prompted to delete the data will be lost. Of course, I just want to format and then install, so please press "enter" to continue, press "L". 6, after the deletion, the C disk will become an unpartitioned division! Press "enter" to continue. 7, here will let you select the disk format. Let me say the difference between NTFS and FTA: First, NTFS has all the benefits of fat, NTFS is less than fat fragments, security i