README.md: add Cygwin dependencies.

[bup.git] / README.md

diff --git a/README.md b/README.md
index cec2b4cbe4f65a675f293817c2f1b305a26b40aa..46b4e7a0d26f677c8cedad3b6c5fea55de9b56da 100644 (file)
--- a/README.md
+++ b/README.md
@@ -71,7 +71,7 @@ Reasons you might want to avoid bup
    for you, but we don't know why.  It is also missing some
    probably-critical features.
    
- - It requires python >= 2.4, a C compiler, and an installed git version >=
+ - It requires python >= 2.5, a C compiler, and an installed git version >=
    1.5.3.1.
  
  - It currently only works on Linux, MacOS X >= 10.4,
@@ -99,9 +99,8 @@ From source
             apt-get install python-pyxattr python-pylibacl
             apt-get install linux-libc-dev
 
-   Substitute python2.5-dev or python2.4-dev if you have an older
-   system.  Alternately, on newer Debian/Ubuntu versions, you can try
-   this:
+   Substitute python2.5-dev if you have an older system.  Alternately,
+   on newer Debian/Ubuntu versions, you can try this:
     
             apt-get build-dep bup
 
@@ -116,6 +115,8 @@ From source
    In addition to the default CentOS repositories, you may need to add
    RPMForge (for fuse-python) and EPEL (for pyxattr and pylibacl).
 
+   On Cygwin, install python, make, rsync, and gcc4.
+
  - Build the python module and symlinks:
 
         make
@@ -257,6 +258,13 @@ Notes on NetBSD/pkgsrc
    anything useful.
 
 
+Notes on Cygwin
+---------------
+
+ - There is no support for ACLs.  If/when some entrprising person
+   fixes this, adjust t/compare-trees.
+
+
 How it works
 ============
 
@@ -327,13 +335,32 @@ mailing list (see below) if you'd like to help.
  
     On the plus side, they actually do have support now, but it's new,
     and not remotely as well tested as tar/rsync/whatever's.  If you'd
-    like to help test, please do; something like 'rsync -niaHAX src/
-    restore/' may be useful on that front.
+    like to help test, please do (see t/compare-trees for one
+    comparison method).
 
     In addition, at the moment, if any strip or graft-style options
     are specified to 'bup save', then no metadata will be written for
     the root directory.  That's obviously less than ideal.
 
+ - bup is overly optimistic about mmap.  Right now bup just assumes
+   that it can mmap as large a block as it likes, and that mmap will
+   never fail.  Yeah, right... If nothing else, this has failed on
+   32-bit architectures (and 31-bit is even worse -- looking at you,
+   s390).
+
+   To fix this, we might just implement a FakeMmap[1] class that uses
+   normal file IO and handles all of the mmap methods[2] that bup
+   actually calls.  Then we'd swap in one of those whenever mmap
+   fails.
+
+   This would also require implementing some of the methods needed to
+   support "[]" array access, probably at a minimum __getitem__,
+   __setitem__, and __setslice__ [3].
+
+     [1] http://comments.gmane.org/gmane.comp.sysutils.backup.bup/613
+     [2] http://docs.python.org/2/library/mmap.html
+     [3] http://docs.python.org/2/reference/datamodel.html#emulating-container-types
+
  - 'bup index' is slower than it should be.
  
     It's still rather fast: it can iterate through all the filenames on my
@@ -414,7 +441,7 @@ and you can subscribe by sending a message to:
 
        bup-list+subscribe@googlegroups.com
 
-Please see <a href="bup/blob/master/HACKING">./HACKING</a> for
+Please see <a href="HACKING">./HACKING</a> for
 additional information, i.e. how to submit patches (hint - no pull
 requests), how we handle branches, etc.