Fix a segfault in the case where the entire recursive scan covers

[sgt/agedu] / agedu.but

diff --git a/agedu.but b/agedu.but
index ff97346..4796c28 100644 (file)
--- a/agedu.but
+++ b/agedu.but
@@ -6,8 +6,8 @@
 
 \U NAME
 
 
 \U NAME
 

-\cw{agedu} - correlate disk usage with last-access times to identify
-large and disused data
+\cw{agedu} \dash correlate disk usage with last-access times to
+identify large and disused data

 
 \U SYNOPSIS
 
 
 \U SYNOPSIS
 


@@ -572,11 +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 file system more than about ten times the above size
-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 \e{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