Chapter 16-Lesson 1-2

• System.Globalization namespace is required for creating culture-sensitive applications.
• As a rule, a culture will be grouped into one of three categories: an invariant culture, a neutral culture, or a specific culture.
• Thread.CurrentThread.CurrentCulture gives a CultureInfo object representing the culture of the system in which the thread is executing.
• We should use formatting options when setting/displaying strings in our applications so that any changes made to the CurrentCulture would propagate to it.
• CurrentUICulture represents the culture for displaying the application and may or may not be the same as CurrentCulture.
• Also, CurrentUICulture must be set at application startup (suitably in Main( ) or Form constructor) which is a behavious opposed to CurrentCulture property. (which may be set at any time.
• The DateTimeFormatInfo class provides a comprehensive set of methods and properties to handle and respond to the dates of different cultures.
• Thread.CurrentThread.CurrentCulture.DateTimeFormat property is used for this purpose. It is of type DateFormatInfo.
• NumberFormat property represents the same case for numbers and currencies.
• CompareInfo property of CultureInfo allows for culture sensitive comparisons (usually for strings)
• CultureRegionAndInfoBuilder class is new in .NET 2.0
• A reference to C:\Windows\.NET Framework\[VERSION]\sysglobl.dll is required to use this class.
• This class takes CultureAndRegionModifiers enumeration value in its second argument for constructor which specifies how much of an existing culture should be loaded in the new custom culture.

Chapter 7-Lesson 2

• There are three operations usually involved with arithmetic operations on variables, i.e. Load Variable value into Register, Change value in Register, Write Back the new value to variable.
• In threaded code, all the above steps/operations are treated as atomic operations.
• Therefore, it might happen that two threads read/load the same variable into the register, change its value equally and write it back, all at the same time. (Valid in multi-core or multi-processor scenario)
• Interlocked class may be used to accertain that a certain variable is accessed by only one thread in a multi-threaded application.
• Interlocked class has static methods which can be used when performing arithmetic operations on variables.
• However, interlocked class has some limitations. It cannot be used for a wide variety of types and cannot be used to make pieces of code thread-safe. (Refer to Page 392)
• To declare a piece of code as thread-safe, use lock keyword to create thread-safe block. Lock keyword requires and object reference passed to it (usually this).
• This creation of lock block is called Synchronization Locks.
• Synchronization Locks may also be created using Monitor class static methods.
• To avoid deadlocks, we may use Monitor.TryEnter( ) method. Otherwise use Timeout.Infinite static property to tell the thread to wait as long as it takes.
• If we wish to deal (synchronize) reading and writing operations seperately, we may use ReaderWriterLock class to lock certain data only for reading or writing.
• LockCookie type object would be required to downgrade a WriterLock to a ReaderLock. (This implies that a WriterLock is downgradable only if it was previously upgraded from a ReaderLock)
• Three OS kernel level objects are represented in .NET by classes named Mutex, Semaphore, AutoResetEvent and ManualResetEvent. All of these derive from WaitHandle class.
• Mutex is almost same as Monitor class with the fact that it allows synchronization across AppDomain and process boundaries.

Chapter 7-Lesson 1

• Thread class is used to create and start a thread.
• ManagedThreadId property may not be the same as operating system thread ID.
• Abort( ) methods actually raises the ThreadAbortException to kill the thread.
• Resume( ) and Suspend( ) methods have been deprecated.
• In order to notify the thread host about the critical region of a thread, use static methods BeginCriticalRegion( ) and EndCriticalRegion( ) of Thread class. Use these methods inside a method that would be used as a thread.
• The static Sleep( ) method blocks the current thread for a certain amount of time during which other threads may run.
• SpinWait( ) does the same but does not allow other thread to run during that time.
• Join( ) method of Thread class asks the host thread to wait until the child/worker thread has finished executing.
• ParameterizedThreadStart delegate is used to represent threads that require parameters/arguments for calling.
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