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Restore grup boot loader after installing windows 7 and 8
Boot-Repair is a simple tool to repair frequent boot issues you may encounter in Ubuntu like when you can’t boot Ubuntu after installing Windows or another Linux distribution, or when you can’t boot Windows after installing Ubuntu, or when GRUB is not displayed anymore, some upgrade breaks GRUB, etc.
Remark: this can also be performed from a live-CD or live-USB.
Either add ‘ppa:yannubuntu/boot-repair’ to your Software Sources via the Software Centre or, for speeds-sake, add it using a new Terminal session:
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sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update sudo apt-get install -y boot-repair && boot-repair |
Boot-Repair can be installed & used from any Ubuntu session (normal session, or live-CD, or live-USB). PPA packages are available for Ubuntu 10.04, 10.10, 11.04, 11.10, 12.04 and 12.10.
vmware workstation 8 kernel modules error fixing
Firstly download
After- Install kernel modules on your ubuntu
$ apt-get install linux-headers-$(uname -r)
After unzip the downloaded file and run .sh files on terminal-
You can change required versions informations inside of .sh files.
and problem fixed.
Tested for vmware workstation .bundle 8.0 version .
mysql performance optimization for restart and connection
skip-name-resolve
To your MySQL configuration file (my.ini/my.cnf) and then be sure to reload (restart) the MySQL database server. The ‘[mysqld]‘ section of the my.cnf file now looks like this:
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[mysqld] port = 3306 socket = /tmp/mysql.sock skip-locking skip-name-resolve |
From Microsoft Windows this can be done from the ‘Services’ window in ‘Administrative tools’ or in Debian/Ubuntu entering this command:
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/etc/init.d/mysql restart |
Calculating the Hamming Code
The key to the Hamming Code is the use of extra parity bits to allow the identification of a single error. Create the code word as follows:
- Mark all bit positions that are powers of two as parity bits. (positions 1, 2, 4, 8, 16, 32, 64, etc.)
- All other bit positions are for the data to be encoded. (positions 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 17, etc.)
- Each parity bit calculates the parity for some of the bits in the code word. The position of the parity bit determines the sequence of bits that it alternately checks and skips.
Position 1: check 1 bit, skip 1 bit, check 1 bit, skip 1 bit, etc. (1,3,5,7,9,11,13,15,…)
Position 2: check 2 bits, skip 2 bits, check 2 bits, skip 2 bits, etc. (2,3,6,7,10,11,14,15,…)
Position 4: check 4 bits, skip 4 bits, check 4 bits, skip 4 bits, etc. (4,5,6,7,12,13,14,15,20,21,22,23,…)
Position 8: check 8 bits, skip 8 bits, check 8 bits, skip 8 bits, etc. (8-15,24-31,40-47,…)
Position 16: check 16 bits, skip 16 bits, check 16 bits, skip 16 bits, etc. (16-31,48-63,80-95,…)
Position 32: check 32 bits, skip 32 bits, check 32 bits, skip 32 bits, etc. (32-63,96-127,160-191,…)
etc. - Set a parity bit to 1 if the total number of ones in the positions it checks is odd. Set a parity bit to 0 if the total number of ones in the positions it checks is even.
Here is an example:
A byte of data: 10011010
Create the data word, leaving spaces for the parity bits: _ _ 1 _ 0 0 1 _ 1 0 1 0
Calculate the parity for each parity bit (a ? represents the bit position being set):
- Position 1 checks bits 1,3,5,7,9,11:
? _ 1 _ 0 0 1 _ 1 0 1 0. Even parity so set position 1 to a 0: 0 _ 1 _ 0 0 1 _ 1 0 1 0 - Position 2 checks bits 2,3,6,7,10,11:
0 ? 1 _ 0 0 1 _ 1 0 1 0. Odd parity so set position 2 to a 1: 0 1 1 _ 0 0 1 _ 1 0 1 0 - Position 4 checks bits 4,5,6,7,12:
0 1 1 ? 0 0 1 _ 1 0 1 0. Odd parity so set position 4 to a 1: 0 1 1 1 0 0 1 _ 1 0 1 0 - Position 8 checks bits 8,9,10,11,12:
0 1 1 1 0 0 1 ? 1 0 1 0. Even parity so set position 8 to a 0: 0 1 1 1 0 0 1 0 1 0 1 0 - Code word: 011100101010.
from : http://users.cs.fiu.edu/~downeyt/cop3402/hamming.html
BITS – M1 M2 M3 M4 M5 M6 M7 M8
Firstly _ C1 – C2 – M1 – C3 – M2 – M3 – C4 – M4 – M5 – M6 -M7 – M8
windows 98 commands
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addusers- arp- assoc- Displays or modifies file extension associations. associate- at- Displays or modifies file extension associations attrib- Displays or changes file attributes. browstat- cacls- Displays or modifies access control lists (ACLs) of files. call- Calls one batch program from another. cd- Displays the name of or changes the current directory. change- chkdsk- Checks a disk and displays a status report chkntfs- Displays or modifies the checking of disk at boot time. choice- Allows for batch files to prompt the user to select one item from a set of single-character choices. cipher - cleanmgr- clip- cmd- Starts a new instance of the Windows command interpreter. color- Sets the default console foreground and background colors. comp- Compares two files or sets of files and displays the differences between them. con2prt- copy- Copies one or more files to another location. date- Displays or sets the date. defrag- Defragments a disk drive. del- Deletes one or more files. delprof- dir- Displays a list of files and subdirectories in a directory. Lists the contents of a directory. diruse- diskcomp- Compares the contents of two floppy disks. diskcopy- Copies the contents of one floppy disk to another. doskey- Edits command lines, recalls Windows commands, and creates macros. dsadd- dsmod- echo- Displays messages, or turns command echoing on or off. endlocal- Ends localization of environment changes in a batch file. erase- Erases one or more files. exit- Quits the CMD.EXE program (command interpreter). expand- fc- Compares two files or sets of files, and displays the differences between them. fdisk- Manipulates hard disk partition tables. The name derives from IBM’s habit of calling hard drives fixed disks. When run from the command line, it displays a menu of various partitioning operations: find- Searches for a text string in a file or files. findstr- Searches for strings in files. for- Runs a specified command for each file in a set of files. forfiles- format- Formats a disk for use with Windows. fsutil- ftp- ftype- Displays or modifies file types used in file extension associations. global- goto- Directs the Windows command interpreter to a labeled line in a batch program. help- Provides Help information for Windows commands. Gives help about DOS. hfnetchk- if- Performs conditional processing in batch programs. ifmember- ipconfig- kill- label- Changes the label on a logical drive, such as a hard disk partition or a floppy disk. ldifde - local- logevent- logoff- logtime- mapisend- md - Creates a directory. mem - Displays memory usage. mode- Configures a system device. monitor- more- Pages through the output so that you can view more than one screen of text. mountvol - move - Moves files or renames directories. moveuser - msg - msiexec- msinfo32 - mstsc - munge - mv - nbtstat- net - netdom - netsh - netstat- netsvc- now- nslookup - ntbackup- ntrights - path - Displays or sets a search path for executable files. pathping - pause - Suspends processing of a batch program and displays the message ‘Press any key to continue perms - ping - popd - Restores the previous value of the current directory saved by PUSHD. portqry - print - Adds a file in the print queue. prncnfg - prnmngr- prompt - Changes the Windows command prompt. pushd - aves the current directory then changes it. qgrep - rasdial- rasphone- rd and- Remove a directory, which by default must be empty of files for the command to succeed (the /s flag removes this restriction). rdisk - recover - Recovers readable information from a bad or defective disk. reg - regedit - regsvr32 - rem - Records comments (remarks) in batch files or CONFIG.SYS. renc- Renames a file or files. replace - Replaces files. rmtshare - robocopy - route - runas - rundll32 - sc - schtasks - sclist - scriptit - set - Displays, sets, or removes Windows environment variables. setlocal - Begins localization of environment changes in a batch file. setx - share - shift - Shifts the position of replaceable parameters in batch files. shortcut - showgrps- showmbrs - shutdown- sleep - soon - sort - A filter to sort lines in the input data stream and send them to the output data stream. start - Starts a separate window to run a specified program or command. su- subinacl - subst - Associates a path with a drive letter. tasklist - time - Displays or sets the system time. timeout - title - Sets the window title for a CMD.EXE session. touch - tracert - type - Displays the contents of a text file. ver - Displays the Windows version. verify- Tells Windows whether to verify that your files are written correctly to a disk. vol - Displays a disk volume label and serial number. where- whoami - windiff - winmsd- winmsdp- wmic - xcacls - xcopy - Copy entire directory trees. |