Solaris™ Internals: Core Kernel Components

8.7. Signals

Signals are a means by which a process or thread can be notified of a particular event. Signals are often compared with hardware interrupts, when a hardware subsystem, such as a disk I/O interface (e.g., a SCSI host adapter), generates an interrupt to a processor as a result of an I/O being completed. The interrupt causes the processor to enter an interrupt handler, so subsequent processing, based on the source and cause of the interrupt, can be done in the operating system. The hardware interrupt analogy maps pretty well to what signals are all about. Similarly, when a signal is sent to a process or thread, a signal handler may be entered (depending on the current disposition of the signal), analogous to the system entering an interrupt ...