INtime® 3.1 Software - tenAsys

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About INtime software’s
RT kernel
This chapter describes objects provided by the RT kernel.
What does the RT kernel provide
The RT kernel provides:
Item
Object management
Time management
Thread management
Memory management
Description
Includes creating, deleting, and manipulating object types defined by
the kernel. Memory for high-level kernel objects is automaticallly taken
from your processor’s memory pool. You must provide memory for lowlevel
kernel objects and may allocate memory beyond the kernel’s
needs to store application specific state information associated with
the low-level object.
Includes an RT clock, alarms that simulate timer interrupts, and the
ability to put threads to sleep.
Includes scheduling locks which protect the currently running thread
from being preempted.
Implements memory pools from which it allocates memory in
response to application requests.
RT 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 (Global
Descriptor Table). 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).
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