Tech Trek: A Software Engineer's Guide to Code and Beyond

This tutorial is for getting started with Android Cloud to Device Messaging (C2DM) on Android. In the iOS world it is knows as “push notifications”. This feature will definitely help developers and their apps to streamline and optimize the data transfers. This would mean that apps now do not have to poll their servers at regular intervals to check for updates. The servers will be able to send updates (like Push Notifications) to the devices and makes it easier for mobile applications to sync data with servers. There are many different ways of accomplishing the same thing(polling,constant server connections,SMS messages). C2DM Alternatives: Polling: The application itself would periodically poll your servers to check for new messages. You would need to implement everything from queuing messages to writing the polling code. Alerts are no good if they’re delayed due to a low polling period but the more frequently you poll, the more the battery is going to die. SMS: Android can...

Shared Memory Shared Memory is an efficeint means of passing data between programs. One program will create a memory portion which other processes (if permitted) can access. In the Solaris 2.x operating system, the most efficient way to implement shared memory applications is to rely on the mmap() function and on the system's native virtual memory facility. Solaris 2.x also supports System V shared memory, which is another way to let multiple processes attach a segment of physical memory to their virtual address spaces. When write access is allowed for more than one process, an outside protocol or mechanism such as a semaphore can be used to prevent inconsistencies and collisions. A process creates a shared memory segment using shmget()|. The original owner of a shared memory segment can assign ownership to another user with shmctl(). It can also revoke this assignment. Other processes with proper permission can perform various control functions on the shared memory segment using s...