Kernel states, the complete list

Here's the complete list of kernel blocking states, with brief explanations of each state. By the way, this list is available in <sys/neutrino.h>—you'll notice that the states are all prefixed with STATE_ (for example, "READY" in this table is listed in the header file as STATE_READY):

If the state is: The thread is:
CONDVAR Waiting for a condition variable to be signaled.
DEAD Dead. Kernel is waiting to release the thread's resources.
INTR Waiting for an interrupt.
JOIN Waiting for the completion of another thread.
MUTEX Waiting to acquire a mutex.
NANOSLEEP Sleeping for a period of time.
NET_REPLY Waiting for a reply to be delivered across the network.
NET_SEND Waiting for a pulse or message to be delivered across the network.
READY Not running on a CPU, but is ready to run (one or more higher or equal priority threads are running).
RECEIVE Waiting for a client to send a message.
REPLY Waiting for a server to reply to a message.
RUNNING Actively running on a CPU.
SEM Waiting to acquire a semaphore.
SEND Waiting for a server to receive a message.
SIGSUSPEND Waiting for a signal.
SIGWAITINFO Waiting for a signal.
STACK Waiting for more stack to be allocated.
STOPPED Suspended (SIGSTOP signal).
WAITCTX Waiting for a register context (usually floating point) to become available (only on SMP systems).
WAITPAGE Waiting for process manager to resolve a fault on a page.
WAITTHREAD Waiting for a thread to be created.

The important thing to keep in mind is that when a thread is blocked, regardless of which state it's blocked in, it consumes no CPU. Conversely, the only state in which a thread consumes CPU is in the RUNNING state.

We'll see the SEND, RECEIVE, and REPLY blocked states in the Message Passing chapter. The NANOSLEEP state is used with functions like sleep(), which we'll look at in the chapter on Clocks, Timers, and Getting a Kick Every So Often. The INTR state is used with InterruptWait(), which we'll take a look at in the Interrupts chapter. Most of the other states are discussed in this chapter.