Re: What is emacs architecture ?

[Chad Brown]

On Jul 19, 2010, at 3:04 PM, Fren Zeee wrote:

> Let me make sure I understand correctly, when I execute the command
> offered by Oscar, it will get all the sources going back to 80's. How
> are they organized and how do I find out which is a consistent
> selection ? Are they organized by incremental diffs ? Take for example
> a file like

I believe that you will find this exercise much, much easier to understand
 if you spend a few minutes (probably ~20-30) learning about Bazaar:

        http://bazaar.canonical.com/en/

Bazaar (invoked and sometimes called `bzr') is a version control system, 
combining something conceptually like incremental diffs and a directed 
graph. 

> Suppose there are 5, 50 or 500 files that go to make emacs, actually i
> dont have any idea of the size. Then out of the 20 versions of each or
> say 20 incremental patches, how does one get the consistent set ?

On my system, the latest sources themselves take up about 120M of 
space, and a fully built tree takes up about 360M of space (that includes 
a `stand-alone bundle' with a copy of all the documentation, elisp, 
support binaries, etc -- which isn't used on most systems).  My emacs 
development area itself is about 800M at the moment; that includes a 
`pristine' source tree, a version of the source tree with my (few) changes, 
a full build and stand-alone bundle mentioned above, and all of the 
history.  If my simple method of counting files isn't terribly off, emacs (not
including history, but including ChangeLogs, docs, sources, etc) is 3117 
files.

For finding a `consistent set', you're really going to want to read up on 
Bazaar first.  The concepts that you want here are `tags' and perhaps 
`branches', but I recommend that you read the overview first.

> How much disk space needed by sources and additional for compilation ?


This varies by system/platform, potentially quite a bit.  I would expect that 
my particular system is on the high end of average, since most platforms 
(as far as I know) don't try to build that stand-alone bundle (which is part 
of the nextstep support, in case you're curious).

This assumes that you already have a functioning development environment,
of course.  If you have to add that (which is likely if you're using, for 
example, 
a stock `MS Windows' platform of some stripe), it'll be much larger.

I hope that helps,
*Chad