Portability and the Ivory Tower (was Re: Book on Microsoft C)

[Jim Shankland]

mcdonald at uxe.cso.uiuc.edu:
	"Portability" is a word seldom heard outside the academic discussions
	of Usenet.

gwyn at smoke.brl.mil (Doug Gwyn):
	That's utter nonsense.[....]

ejd at caen.engin.umich.edu (Edward J Driscoll):
	Sure, but there are also numerous developers who use all kinds of
	non-portable code in order to get the best performance they can.
	The majority of users probably only use a particular application
	on one particular system, so they're not going to be attracted
	by portability....

First, I have to take Doug Gwyn to task for insufficient constructive
snottiness (as Padlipsky would say).  "Utter nonsense" is a *big*
understatement.

Second, it's a canard that there is a direct tradeoff between portability
and performance.  In most cases, the performance impact is unnoticeable,
and the (very) few cases where it makes a difference can be carefully
isolated.  Learning to code portably can take a little extra programmer time
and discipline up front; even once the skill is learned, portable coding
*may* take a little extra development time.  It's worth it.

Third, it's not the *users* who pay the price of non-portable code
(at least, not directly); it's the software vendors.  A particular
user may (or may not) be interested in the product on only one
system; but there are potential users of the product on all sorts
of systems.  The commercial importance of different platforms is
constantly changing.  Non-portable coding artificially limits the
lifetime and the potential user community of a piece of software.
Software vendors who can't be bothered to produce portable code
finish last.

Those are the facts.  Flout them at your own (or your employer's) risk.

Jim Shankland
jas at ernie.berkeley.edu

"Blame it on the lies that killed us, blame it on the truth that ran us down"