Monthly Archives: April 2010

Starvation In computer science, starvation is a multitasking-related problem, where a process is perpetually denied necessary resources. Without those resources, the program can never finish its task. Starvation is similar in effect to deadlock. Two or more programs become deadlocked … Continue reading →

Threads vs. Processes Processes Both threads and processes are methods of parallelizing an application. However, processes are independent execution units that contain their own state information, use their own address spaces, and only interact with each other via interprocess communication … Continue reading →

Mutex vs. Semaphore, what is the difference? The Toilet Example Mutex Is a key to a toilet. One person can have the key – occupy the toilet – at the time. When finished, the person gives (frees) the key to … Continue reading →

Use the following appender to show different colors. You can also customize the color per level. log4perl.appender.SCREEN = Log::Log4perl::Appender::ScreenColoredLevels log4perl.appender.SCREEN.color.INFO = white log4perl.appender.SCREEN.color.FATAL= bold underline blink red on_white attributes BOLD, DARK, UNDERLINE, UNDERSCORE, BLINK colors BLACK, RED, GREEN, YELLOW, BLUE, … Continue reading →

http://perldoc.perl.org/Term/ANSIColor.html use Term::ANSIColor; print color ‘bold blue’; print “This text is bold blue.\n”; print color ‘reset’; print “This text is normal.\n”; print colored (“Yellow on magenta.”, ‘yellow on_magenta’), “\n”; print “This text is normal.\n”; print colored ['yellow on_magenta'], ‘Yellow on … Continue reading →

Make the unique key long enough to allow for reasonable duplication of names in the real world For example, for a table of people, a unique key of country/state/city/address might be a good choice.  This allows for two people in … Continue reading →

my @fields = ( “country_name”, “region_name”, “city_name”, ); while (my $row = $sth->fetchrow_hashref) { my %row = %$row; printf $format, @row{ @fields }; }

Store phone numbers as strings, not numbers. Phone numbers are identifiers that happen to use digits. Phone numbers starting with zero are valid, but may be interpreted as octal by a programming language. Strip the phone number to only digits … Continue reading →