Optimisations in HTML generation: do not keep calling get_indices()

[sgt/agedu] / agedu.but

diff --git a/agedu.but b/agedu.but
index a6a5dfe..f4fdb1d 100644 (file)
--- a/agedu.but
+++ b/agedu.but
@@ -68,7 +68,10 @@ along the lines of
 \c URL: http://127.164.152.163:48638/
 
 (That URL will always begin with \cq{127.}, meaning that it's in the
 \c URL: http://127.164.152.163:48638/
 
 (That URL will always begin with \cq{127.}, meaning that it's in the

-\cw{localhost} address space.)
+\cw{localhost} address space. So only processes running on the same
+computer can even try to connect to that web server, and also there
+is access control to prevent other users from seeing it \dash see
+below for more detail.)

 
 Now paste that URL into your web browser, and you will be shown a
 graphical representation of the disk usage in \cw{/home/fred} and
 
 Now paste that URL into your web browser, and you will be shown a
 graphical representation of the disk usage in \cw{/home/fred} and


@@ -241,9 +244,11 @@ whereas \cw{-S} will not.
 
 \lcont{
 
 
 \lcont{
 

-(Actually, the output will not be exactly identical, due to a
-difference in treatment of last-access times on directories. See the
-documentation of the \cw{--dir-atime} option in the next section.
+(The output will not be exactly \e{identical}, due to a
+difference in treatment of last-access times on directories.
+However, it should be effectively equivalent for most purposes. See
+the documentation of the \cw{--dir-atime} option in the next section
+for further detail.)

 
 }
 
 
 }
 


@@ -438,6 +443,20 @@ complexity.)
 
 }
 
 
 }
 

+\dt \cw{--mtime}
+
+\dd This option causes \cw{agedu} to index files by their last
+modification time instead of their last access time. You might want
+to use this if your last access times were completely useless for
+some reason: for example, if you had recently searched every file on
+your system, the system would have lost all the information about
+what files you hadn't recently accessed before then. Using this
+option is liable to be less effective at finding genuinely wasted
+space than the normal mode (that is, it will be more likely to flag
+things as disused when they're not, so you will have more candidates
+to go through by hand looking for data you don't need), but may be
+better than nothing if your last-access times are unhelpful.
+

 The following options affect the web server mode \cw{-w}, and in one
 case also the stand-along HTML generation mode \cw{-H}:
 
 The following options affect the web server mode \cw{-w}, and in one
 case also the stand-along HTML generation mode \cw{-H}:
 


@@ -476,8 +495,8 @@ three months ago or later.
 \cw{agedu} should listen when running its web server. If you want
 \cw{agedu} to listen for connections coming in from any source, you
 should probably specify the special IP address \cw{0.0.0.0}. If the
 \cw{agedu} should listen when running its web server. If you want
 \cw{agedu} to listen for connections coming in from any source, you
 should probably specify the special IP address \cw{0.0.0.0}. If the

-port number is omitted, it will be assumed to be 80 (for which
-\cw{agedu} will probably need to be running as a privileged user).
+port number is omitted, an arbitrary unused port will be chosen for
+you and displayed.

 
 \lcont{
 
 
 \lcont{
 


@@ -553,11 +572,13 @@ efficiently perform the queries it needs; this data structure
 requires \cw{O(N log N)} storage. This is larger than you might
 expect; a scan of my own home directory, containing half a million
 files and directories and about 20Gb of data, produced an index file
 requires \cw{O(N log N)} storage. This is larger than you might
 expect; a scan of my own home directory, containing half a million
 files and directories and about 20Gb of data, produced an index file

-nearly a third of a Gb in size. Furthermore, since the data file
-must be memory-mapped during most processing, it can never grow
-larger than available address space, which means that any use of
-\cw{agedu} on a seriously large file system is probably going to
-have to be done on a 64-bit computer.
+over 60Mb in size. Furthermore, since the data file must be
+memory-mapped during most processing, it can never grow larger than
+available address space, so a \em{really} big filesystem may need to
+be indexed on a 64-bit computer. (This is one reason for the
+existence of the \cw{-D} and \cw{-L} options: you can do the
+scanning on the machine with access to the filesystem, and the
+indexing on a machine big enough to handle it.)

 
 The data structure also does not usefully permit access control
 within the data file, so it would be difficult \dash even given the
 
 The data structure also does not usefully permit access control
 within the data file, so it would be difficult \dash even given the