INtime kernel

This topic contains these sections:

What the INtime kernel provides
INtime kernel objects

What the INtime kernel provides

The RT kernel provides a number of services for real-time applications:

Object management	Manages creating, deleting, and manipulating object types defined by the kernel.
Time management	Provides time-of-day, time synchronization and alarm services.
Thread management	Manages thread scheduling, synchronization and run-time statistics.
Memory management	Manages physical and virtual memory for nodes and processes.
Interrupt management	Manages hardware interrupts and from I/O devices.
Global Objects (GOBS)	A protocol providing a communications layer for access to objects on other nodes.
Distributed System Manager (DSM)	Provides system and process monitoring services.
Windows Registry access	Provides a registry interface to real-time applications.

INtime kernel objects

Objects, data structures that occupy memory, are building blocks that application programs manipulate. Each object type has a specific set of attributes or characteristics. Once you learn the attributes of, for example, a mailbox, you know how to use all mailboxes.

Object-based programming, which concentrates on objects and operations performed on them, is compatible with modular programming. Typically a single thread performs only a few related functions on a few objects.

The RT kernel provides basic objects and maintains the data structures that define these objects and their related system calls. When you create an object, the RT kernel returns a handle that identifies the object:

High-level objects consume memory, but also a slot in the system GDT. Therefore, the maximum number of high-level objects allowed in the system at any one time is approximately 7600 (8192 slots in a GDT minus slots used by the operating system).
Low-level objects consume only memory. Therefore, only the amount of system memory controls how many low-level objects can be present at a given time.

The RT kernel provides these objects.

Object	Description
Threads	Do the work of the system and respond to interrupts and events.
Processes	Environments where threads do their work.
Semaphores	Used by threads to synchronize.
Regions	Used by threads to provide mutual exclusion.
Mailboxes	Used by threads to pass objects and data. INtime software includes both object and data mailboxes.
Message Queues	Used by threads to pass data messages.
Ports	Used by threads to synchronize operations, pass messages, and access INtime services.
Memory objects	Encapsulates physical memory for sharing between processes and nodes.