LNB

Low Noise Block Downconverter. A device that processes weak satellite signals directed by an antenna reflector into a feedhorn, whilst introducing as little electrical noise as possible in the process. An LNB consists of a microwave detector followed by a high gain, low noise microwave amplifier and a frequency converter, which downconverts a block of frequencies (group of satellite signals) to a lower intermediate frequency range (typically 950 to 2150 MHz). The feed horn is often integrated with LNB in a single mechanical unit.

What is priority inverse? How to avoid it?

A situation where a low-priority task holds a resource
which a higher-priority task is waiting for. This can
occur with tasks scheduled with SCHED_OTHER or SCHED_IDLE,
where a task with a higher scheduling priority will always
be scheduled before in preference. This leads to deadlock as
the low-priority task cannot be scheduled in order to release
the lock, and the high-priority task can't continue without the
lock on the resource. Priority inheritance is a putative solution,
where the low-priority task temporarily takes on the priority of
the other task, enabling its scheduling and release of the lock.
However this approach can itself lead to deadlock
(FIXME: is this really true?).

www.kernelnewbies.org/glossary/

Context switch

The execution is changed from one context (thread) to another.

Definition 2 for Preemption

The act of suspending the execution of one thread
and starting (or resuming) another. The suspended
thread is said to have been "preempted" by the new
thread. In QNX, whenever a lower-priority thread is
actively consuming the CPU, and a higher-priority
thread becomes READY, the lower-priority thread is
immediately preempted by the higher-priority thread.

www.qnx.com/developer/docs/momentics_nc_docs
/neutrino/sys_arch/glossary.html

Preemption

When a thread is interrupted, and the execution is handed over to another thread using a context switch.

Kernel

The kernel of an RTOS is the part that schedules which thread gets to execute at a given point in time.

Kernal is an bridge between OS and Hardware.

Kernal is the heart the of OS, usally kernal only operate both the hardwar and software.
The operating system is nothing but wrapper of the kerenal, through OS user can achive
kernal operations easily ( user friendly ).

OS is an interface between user and computer.

Task

In this text, a task is something that needs to be done. It is often implemented in a separate thread, but does not have to be.

Process

An environment in which one or several threads run.
Examples of the context is the global memory address,
which is common for threads within a process. Note that
a process in itself does not execute code, but one or more
threads within the process can. In some systems that
does not have memory protection threads are sometimes
called processes. This should be avoided since it will only
lead to confusion.

Thread

A thread is the primitive that can execute code. It contains an instruction pointer (= program counter) and sometimes has its own stack.

RTOS and Normal OS

Difference Between RTOS and normal OS
RTOS has priority based preemption but normal OS not have.

RTOS

WHAT IS RTOS?
An operating system designed specifically for use in real-time systems that respond to external eventswithin a short and predictable time frame.