• Law 1: The remaining work to finish in order to reach your

goal increases as the deadline approaches.• Law 2:

Adding manpower to a late software project makes it later

• Law 5: Any sufficiently advanced technology is

indistinguishable from magic.• Law 7:

Every task takes twice as long as you think it will take. If you double the time you think it will take,

it will actually take four times as long.

Murphy's Computer Laws

• Law 8:There is always one item on the screen menu that is

mislabeled and should read "ABANDON HOPE ALL YE WHO ENTER HERE".

• Law 14: In case of doubt, make it sound convincing.

• Law 15:Program results should always be reproducible.

They should all fail in the same way.• Law 16:

Do not believe in miracles. Rely on them.

Murphy's Computer Laws

• Law 20: Undetectable errors are infinite in variety, in contrast to detectable errors, which by definition are limited.

• Law 21: Investment in reliability will increase until it exceeds

the probable cost of errors or until someone insists on getting some useful work done.

• Law 22: The amount of expertise varies in inverse proportion to the

number of statements understood by the general public.• Law 30:

Program complexity grows until it exceeds the capabilityof the programmer who must maintain it.

Murphy's Computer Laws

• Law 32: Inside every large program is a small

program struggling to get out.• Law 37:

The first 90% of the task takes 90% of the time, & the last ten 10% takes the other 90%.

• Law 52: Badness comes in waves.

• Law 54: After designing a useful routine that gets around a familiar bug

in the system, the system is revised, the bug is taken

away, and you're left with a useless routine.

Murphy's Computer Laws

• Law 56: That's not a bug, that's a feature!

• Law 59: Once you open a can of worms, the only way to

recan them is to use a larger can.• Lubarsky's Law of Cybernetic Entomology:

There's always one more bug.• (Douglas) Hofstadter's Law:

Any computer project will take twice as long as you think it will even when you take into

account Hofstadter's law.• Woltman's Law:

Never program and drink beer at the same time.

Murphy's Computer Laws