[Scottish] Computing Power debate

George Richard Russell scottish at mailman.lug.org.uk
Tue Oct 1 11:37:01 2002

On Tuesday 01 Oct 2002 11:03 am, you wrote:

> As for why C is popular: it does the job, its *largely* portable and, if
> you abstract out hardware differences, it can be made portable. What more
> do you _need_?

Polymorphism, first class functions, an unbroken type system, string support, 
standard networking, threading etc

Perhaps I'm just spoilt.

> > 2. High level languages like python can, in theory, be much quicker
> > than low level languages: http://psyco.sourceforge.net/introduction.html

> But I'd say this is more because the language is interpreted rather than
> it being high or low level. If a language is compiled, then your stuffed:
> the compiler produces what it thinks of as the best code but it wont take
> into account any hot-spots.

Many interpreters compile to an intermediate form, which is then interpreted 
- hence bytecode. This can then be JIT compiled at run time.

> > 3. Language choice is totally epsilon compared to algorithim choice,
> > the difference between C and Python is prolly in the order of 10% at
> > worst, the difference between a skip list and a linked list is so much
> > more.

Um, python is several orders of magnitude slower. Interpreters tend at best 
to be twice as slow, often ten times a slow, and for pure interpreters, often 
a 1000 times slower than compiled machine code.


C code for Sieve of Eratosthenes ~ under a quarter of a second
Python code - 47 seconds

Language choice is important for developer productivity. Choose a language 
suitable for the task. (in most cases, anything other than C).

Once it works, it can be optimised. Until it works, its useless.