Subject: Re: RFC: /kern/summary
To: Systems Anarchist <>
From: Henry Miller <>
List: tech-kern
Date: 03/10/1999 23:07:43
On Wed, 10 Mar 1999, Systems Anarchist wrote:

> 	>Historically, unix systems have, for the most part, used
> 	>single_case_underscore_separated_identifiers, not
> 	>MixedCaseMashedTogetherIdentifiers.
> 	I thought that, historically, Unix has used six character identifiers
> 	(later seven chars) and no underscores for lack of space.
> That hasn't been true for a long, long time, if it ever was.  Take a 
> look at the v6 kernel source in the Lions book; you'll see identifiers
> as long as 13 characters, as well as underscores (though they did tend to
> use underscores more sparingly than the UCB people later would).

My understanding was that the first six were required to be UNIQUE.  That
is you could have as many characters as you cared to use, but the compiler
was only required to use the first 6.  

As justification let me site part 9.  Note that this
only applies to external identifiers.   I wish I knew where the orginial
came from, but this is at least some justification for saying that 6
characters is historical.