Kernel Panic - History

History

The Unix kernel maintains internal consistency and runtime correctness with assertions as the fault detection mechanism. The basic assumption is that the hardware and the software should perform correctly and a failure of an assertion results in a panic, i.e. a voluntary halt to all system activity. The kernel panic was introduced in an early version of Unix and demonstrated a major difference between the design philosophies of Unix and its predecessor Multics. Multics developer Tom van Vleck recalls a discussion of this change with Unix developer Dennis Ritchie:

“ I remarked to Dennis that easily half the code I was writing in Multics was error recovery code. He said, "We left all that stuff out. If there's an error, we have this routine called panic, and when it is called, the machine crashes, and you holler down the hall, 'Hey, reboot it.'" ”

The original panic function was essentially unchanged from Fifth Edition UNIX to the VAX-based UNIX 32V and output only an error message with no other information, then dropped the system into an endless idle loop.

Source code of panic function in UNIX V6:

/* * In case console is off, * panicstr contains argument to last * call to panic. */ char *panicstr; /* * Panic is called on unresolvable * fatal errors. * It syncs, prints "panic: mesg" and * then loops. */ panic(s) char *s; { panicstr = s; update; printf("panic: %s\n", s); for(;;) idle; }

As the Unix codebase was enhanced, the panic function was also enhanced to dump various forms of debugging information to the console.

Read more about this topic:  Kernel Panic

Famous quotes containing the word history:

    ““And now this is the way in which the history of your former life has reached my ears!” As he said this he held out in his hand the fatal letter.”
    —Anthony Trollope (1815–1882)

    “Whenever we read the obscene stories, the voluptuous debaucheries, the cruel and torturous executions, the unrelenting vindictiveness, with which more than half the Bible is filled, it would be more consistent that we called it the word of a demon than the Word of God. It is a history of wickedness that has served to corrupt and brutalize mankind.”
    —Thomas Paine (1737–1809)

    “Three million of such stones would be needed before the work was done. Three million stones of an average weight of 5,000 pounds, every stone cut precisely to fit into its destined place in the great pyramid. From the quarries they pulled the stones across the desert to the banks of the Nile. Never in the history of the world had so great a task been performed. Their faith gave them strength, and their joy gave them song.”
    —William Faulkner (1897–1962)