The functionality of the kernel is broken down into separate processes,usually called servers. Ideally,only the servers absolutelyrequiring such capabilities run in a privileged execution mode. The rest of the servers run in user-space. All the servers,though,are separated into different address spaces. Therefore,direct function invocation as in monolithic kernels is not possible. Instead, microkernels communicate via message passing: An interprocess communication (IPC) mechanism is built into the system,and the various servers communicate with and invoke “services” from each other by sending messages overthe IPC mechanism.
TECHNICAL QUESTIONS AND ANSWERS
A Collection Of Technical Questions. Study & Apply.
Wednesday, April 09, 2014
What is Monolithic kernel
Monolithic kernels are the simpler design. All kernels were designed in this manner until the 1980s. Monolithic kernels are implemented entirely as a single process running in a single address space. All kernel services exist and execute in the large kernel address space. Communication within the kernel is trivial because everything runs in kernel mode in the same address space: The kernel can invoke functions directly,as a user-space application might. Proponents of this model cite the simplicity and performance of the monolithic approach. MostUnixsystems are monolithic in design.
Tuesday, April 08, 2014
High Efficiency Video Coding( HEVC )
High Efficiency Video Coding (HEVC) is a video compression standard, a successor to H.264/MPEG-4 AVC (Advanced Video Coding), that was jointly developed by the ISO/IEC Moving Picture Experts Group (MPEG) and ITU-T Video Coding Experts Group (VCEG).
HEVC is said to double the data compression ratio compared to H.264/MPEG-4 AVC at the same level of video quality. It can alternatively be used to provide substantially improved video quality at the same bit rate. It can support 8K UHD and resolutions up to 8192x4320.
The first version of the standard was completed and published in early 2013. Several extensions to the technology remain under active development, including range extensions (supporting enhanced video formats), scalable coding extensions, and 3D video extensions.
Tuesday, April 01, 2014
What is the state of the processor, when a process is waiting for some event to occur?
When a process is waiting for some event to take place, most likely for the needy resources to be relased by other process or processes that are currently utilizing the resources, such as an I/O device, it is at a blocked state. Upon the availability of waited resources, after the resources being relased, the process will transit to a ready state from this blocked state.
What is Deadlock?
Deadlock is a situation in which the processes waits for the other resource which is occupied by another process in a loop for example take processes P1 and P2 and resources R1 and R2 in the deadlock condition,
- P1 -R1 waits for R2
- P2 -R2 waits for R1 so
both processes waits for the other resource to get free for their complete operation. In such cases - One can avoid deadlocks by following methods
1) Prevention
2) Detection
3) Avoidance
4) Recovery
Monday, November 25, 2013
EPG - Electronic Program Guide
EPG gives the information to the user about the events of a services present in DVB. The EPG data is sent through EIT (Event Information Table). The information such as, Program name, Start Date, Start Time, Duration, Short and Detailed description are possible with this EIT data.
The information comes under EIT are classified into three categories, they are,
The information comes under EIT are classified into three categories, they are,
- Current/Next Information
- Event Schedule
- Extended Info
Wednesday, September 18, 2013
Java Script Code for converting MJD to date(YMD)
// Convert mjd to/from Month, Day, Year,
function MJDtoYMD (mjd_in)
{
var year;
var month;
var day;
var hour;
var jd;
var jdi;
var jdf
var l;
var n;
// Julian day
jd = Math.floor (mjd_in) + 2400000.5;
// Integer Julian day
jdi = Math.floor (jd);
// Fractional part of day
jdf = jd - jdi + 0.5;
// Really the next calendar day?
if (jdf >= 1.0) {
jdf = jdf - 1.0;
jdi = jdi + 1;
}
hour = jdf * 24.0;
l = jdi + 68569;
n = Math.floor (4 * l / 146097);
l = Math.floor (l) - Math.floor ((146097 * n + 3) / 4);
year = Math.floor (4000 * (l + 1) / 1461001);
l = l - (Math.floor (1461 * year / 4)) + 31;
month = Math.floor (80 * l / 2447);
day = l - Math.floor (2447 * month / 80);
l = Math.floor (month / 11);
month = Math.floor (month + 2 - 12 * l);
year = Math.floor (100 * (n - 49) + year + l);
if (month < 10)
month = "0" + month;
if (day < 10)
day = "0" + day;
//year = year - 1900;
return (new Array (year, month, day));
}
function MJDtoYMD (mjd_in)
{
var year;
var month;
var day;
var hour;
var jd;
var jdi;
var jdf
var l;
var n;
// Julian day
jd = Math.floor (mjd_in) + 2400000.5;
// Integer Julian day
jdi = Math.floor (jd);
// Fractional part of day
jdf = jd - jdi + 0.5;
// Really the next calendar day?
if (jdf >= 1.0) {
jdf = jdf - 1.0;
jdi = jdi + 1;
}
hour = jdf * 24.0;
l = jdi + 68569;
n = Math.floor (4 * l / 146097);
l = Math.floor (l) - Math.floor ((146097 * n + 3) / 4);
year = Math.floor (4000 * (l + 1) / 1461001);
l = l - (Math.floor (1461 * year / 4)) + 31;
month = Math.floor (80 * l / 2447);
day = l - Math.floor (2447 * month / 80);
l = Math.floor (month / 11);
month = Math.floor (month + 2 - 12 * l);
year = Math.floor (100 * (n - 49) + year + l);
if (month < 10)
month = "0" + month;
if (day < 10)
day = "0" + day;
//year = year - 1900;
return (new Array (year, month, day));
}
Monday, February 06, 2012
List of DOS commands
How to get list of DOS commands?
In command prompt execute the 'help' command, you will get it.
C:\TechQues>help
In command prompt execute the 'help' command, you will get it.
C:\TechQues>help
C:\TechQues>help ASSOC Displays or modifies file extension associations. ATTRIB Displays or changes file attributes. BREAK Sets or clears extended CTRL+C checking. BCDEDIT Sets properties in boot database to control boot loading. 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. CHCP Displays or sets the active code page number. CHDIR Displays the name of or changes the current directory. CHKDSK Checks a disk and displays a status report. CHKNTFS Displays or modifies the checking of disk at boot time. CLS Clears the screen. CMD Starts a new instance of the Windows command interpreter. COLOR Sets the default console foreground and background colors. COMP Compares the contents of two files or sets of files. COMPACT Displays or alters the compression of files on NTFS partitions. CONVERT Converts FAT volumes to NTFS. You cannot convert the current drive. COPY Copies one or more files to another location. DATE Displays or sets the date. DEL Deletes one or more files. DIR Displays a list of files and subdirectories in a directory. DISKCOMP Compares the contents of two floppy disks. DISKCOPY Copies the contents of one floppy disk to another. DISKPART Displays or configures Disk Partition properties. DOSKEY Edits command lines, recalls Windows commands, and creates macros. DRIVERQUERY Displays current device driver status and properties. ECHO Displays messages, or turns command echoing on or off. ENDLOCAL Ends localization of environment changes in a batch file. ERASE Deletes one or more files. EXIT Quits the CMD.EXE program (command interpreter). FC Compares two files or sets of files, and displays the differences between them. 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. FORMAT Formats a disk for use with Windows. FSUTIL Displays or configures the file system properties. FTYPE Displays or modifies file types used in file extension associations. GOTO Directs the Windows command interpreter to a labeled line in a batch program. GPRESULT Displays Group Policy information for machine or user. GRAFTABL Enables Windows to display an extended character set in graphics mode. HELP Provides Help information for Windows commands. ICACLS Display, modify, backup, or restore ACLs for files and directories. IF Performs conditional processing in batch programs. LABEL Creates, changes, or deletes the volume label of a disk. MD Creates a directory. MKDIR Creates a directory. MKLINK Creates Symbolic Links and Hard Links MODE Configures a system device. MORE Displays output one screen at a time. MOVE Moves one or more files from one directory to another directory. OPENFILES Displays files opened by remote users for a file share. PATH Displays or sets a search path for executable files. PAUSE Suspends processing of a batch file and displays a message. POPD Restores the previous value of the current directory saved by PUSHD. PRINT Prints a text file. PROMPT Changes the Windows command prompt. PUSHD Saves the current directory then changes it. RD Removes a directory. RECOVER Recovers readable information from a bad or defective disk. REM Records comments (remarks) in batch files or CONFIG.SYS. REN Renames a file or files. RENAME Renames a file or files. REPLACE Replaces files. RMDIR Removes a directory. ROBOCOPY Advanced utility to copy files and directory trees SET Displays, sets, or removes Windows environment variables. SETLOCAL Begins localization of environment changes in a batch file. SC Displays or configures services (background processes). SCHTASKS Schedules commands and programs to run on a computer. SHIFT Shifts the position of replaceable parameters in batch files. SHUTDOWN Allows proper local or remote shutdown of machine. SORT Sorts input. START Starts a separate window to run a specified program or command. SUBST Associates a path with a drive letter. SYSTEMINFO Displays machine specific properties and configuration. TASKLIST Displays all currently running tasks including services. TASKKILL Kill or stop a running process or application. TIME Displays or sets the system time. TITLE Sets the window title for a CMD.EXE session. TREE Graphically displays the directory structure of a drive or path. 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. XCOPY Copies files and directory trees. WMIC Displays WMI information inside interactive command shell.
Sunday, February 05, 2012
Solution for 'This virtual machine appears to be in use'
VMWare Workstation
Some time if you shutdown the VMWare Workstation improper, you will get 'This virtual machine appears to be in use' error message at the time of next boot. To resolve this issue follow this instruction.
Simply go to the folder where we have placed the physical files for the specific virtual machine and just delete the folders which are ending with "*.vmx.lck" and you are done.
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