Data Structures

• Capability: globally identifies and protects an object.
• Message_Header: specifies the information needed to deliver a message.

System Calls

• act: invokes a method on an object.
• send: sends a message to a mailbox.
• receive: receives a message from a mailbox. 

Kernel Service Stubs

Memory Services

• segment_create: creates a new memory segment.
• segment_destroy: destroys a memory segment.
• segment_status: returns the status of a memory segment. 
• segment_attach: attaches a memory segment to the running task's address space.
• segment_detach: detaches a memory segment from the running task's address space. 
• segment_resize: resizes a memory segment.

Task Services

• task_create: creates a new task.
• task_destroy: destroys a task.
• task_status: returns the status of a task.
• task_self: returns a owner capability for the current task.
• task_exit: destroys the current task.
• task_wait: waits for the termination of a task.

Thread Services

• thread_create: creates a new thread.
• thread_destroy: destroys a thread.
• thread_status: returns the status of a thread.
• thread_self: returns a owner capability for the current thread.
• thread_exit: destroys the current thread.
• thread_wait: waits for the termination of a thread.
• thread_sleep: makes a thread to sleep for a certain time.
• thread_yield: yields the caller's time slice for another thread to run.
• thread_suspend: suspends the execution of a thread.
• thread_resume: resumes the execution of a thread.

Semaphore Services

• semaphore_create: creates a new semaphore.
• semaphore_destroy: destroys a semaphore. 
• semaphore_status: returns the status of a semaphore.
• semaphore_p: issues a P on a semaphore.
• semaphore_v: issues a V on a semaphore.

Mailbox Services

• mailbox_create:  creates a new mailbox. 
• mailbox_destroy: destroys a mailbox. 
• mailbox_status: returns the status of a mailbox. 
• act: invokes a method on an object (system call).
• send: sends a message to a mailbox (system call).
• receive: receives a message from a mailbox (system call).

Interrupt Services

• interrupt_create: creates a new interruption handler.
• interrupt_destroy:  destroys an interruption handler.
• interrupt_status: returns the status of an interruption handler.

Debug Services

• debug_clrscr: clears the screen. 
• debug_print: prints to the screen.