[30897] in North American Network Operators' Group
Re: ARIN Policy on IP-based Web Hosting
daemon@ATHENA.MIT.EDU (David Charlap)
Fri Sep 1 08:48:53 2000
Message-ID: <39AFA4E9.54081F88@marconi.com>
Date: Fri, 01 Sep 2000 08:45:29 -0400
From: David Charlap <david.charlap@marconi.com>
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"Roeland M.J. Meyer" wrote:
>
> everything to the right side of the final dot. Such as in
> "/etc/named.conf" the extension is "conf". A better example is
> "/usr/local/src/whois.1.9.0/readme.txt" where the extension is "txt".
True, in a literal understanding.
But in the sense of "a part of the filename used to identify the format
or purpose of the file content", it's not always correct.
"extension" is a term that stems from the DOS days, when it was actually
stored separately in the directory structure of the file system.
Today, however, you find this information encoded into filenames in a
wide variety of ways. Type information may be in the form of a prefix,
a suffix, multiple prefixes, or multiple suffixes. It may be delimited
by periods, dashes, other characters, or even by no characters at all.
For example:
conf.modules
myarchive.tar.gz
libstdc++-2-libc6.1-1-2.9.0.a
kernel-headers-2.2.16-3.i386.rpm
An "extension" is only one specific subset of the infinite number of
possible ways that type information can be, and often is, encoded into
filenames.
Unfortunately, this creates the reality that any code which tries to
deduce a file type from a filename will require a huge (and ever
increasing) set of parsing rules (probably some form of regular
expressions) in order to to the job properly.
Even more unfortunately, the Windows world hasn't figured this out yet,
and only looks at strings that follow a period at the end of a name.
-- David
