diff --git a/sbin/dump/dump.8 b/sbin/dump/dump.8
index e20dacb1de9e..87b8577b740f 100644
--- a/sbin/dump/dump.8
+++ b/sbin/dump/dump.8
@@ -53,7 +53,11 @@
 .Op Fl T Ar date
 .Ar filesystem
 .Nm
-.Op Fl W Li \&| Fl w
+.Fl W | Fl w
+.Pp
+.Nm rdump
+is an alternate name for
+.Nm .
 .Pp
 .in \" XXX
 (The
@@ -83,17 +87,23 @@ On media that cannot reliably return an end-of-media indication
 (such as some cartridge tape drives)
 each volume is of a fixed size;
 the actual size is determined by the tape size and density and/or
-block count options below.
+.Fl B
+options.
 By default, the same output file name is used for each volume
 after prompting the operator to change media.
 .Pp
+The filesystem to be dumped is specified by the argument
+.Ar filesystem
+as either its device-special file or its mount point
+(if that is in a standard entry in /etc/fstab).
+.Pp
 The following options are supported by
 .Nm :
 .Bl -tag -width Ds
 .It Fl 0\-9
 Dump levels.
 A level 0, full backup,
-guarantees the entire file system is copied
+guarantees the entire filesystem is copied
 (but see also the
 .Fl h
 option below).
@@ -112,11 +122,15 @@ recommended when appending to an existing tape, or using a tape
 drive with hardware compression (where you can never be sure about
 the compression ratio).
 .It Fl B Ar records
-The number of 1 KB blocks per volume.
+The number of kilobytes per output volume, except that if it is
+not an integer multiple of the output block size,
+the command uses the next smaller such multiple.
 This option overrides the calculation of tape size
 based on length and density.
 .It Fl b Ar blocksize
-The number of kilobytes per dump record.
+The number of kilobytes per output block, except that if it is
+larger than 64, the command uses 64. (See the BUGS section.)
+The default block size is 10.
 .It Fl c
 Change the defaults for use with a cartridge tape drive, with a density
 of 8000 bpi, and a length of 1700 feet.
@@ -243,7 +257,7 @@ but the
 option may be used to change it.
 .It Fl W
 .Nm Dump
-tells the operator what file systems need to be dumped.
+tells the operator what filesystems need to be dumped.
 This information is gleaned from the files
 .Pa dumpdates
 and
@@ -252,12 +266,12 @@ The
 .Fl W
 option causes
 .Nm
-to print out, for each file system in
+to print out, for each filesystem in
 the
 .Pa dumpdates
 file
 the most recent dump date and level,
-and highlights those file systems that should be dumped.
+and highlights those filesystems that should be dumped.
 If the
 .Fl W
 option is set, all other options are ignored, and
@@ -343,8 +357,7 @@ Always start with a level 0 backup, for example:
 This should be done at set intervals, say once a month or once every two months,
 and on a set of fresh tapes that is saved forever.
 .It
-After a level 0, dumps of active file
-systems are taken on a daily basis,
+After a level 0, dumps of active filesystems are taken on a daily basis,
 using a modified Tower of Hanoi algorithm,
 with this sequence of dump levels:
 .Bd -literal -offset indent
@@ -355,7 +368,7 @@ For the daily dumps, it should be possible to use a fixed number of tapes
 for each day, used on a weekly basis.
 Each week, a level 1 dump is taken, and
 the daily Hanoi sequence repeats beginning with 3.
-For weekly dumps, another fixed set of tapes per dumped file system is
+For weekly dumps, another fixed set of tapes per dumped filesystem is
 used, also on a cyclical basis.
 .El
 .Pp
@@ -378,7 +391,7 @@ see the
 .Fl D
 option)
 .It Pa /etc/fstab
-dump table: file systems and frequency
+dump table: filesystems and frequency
 .It Pa /etc/group
 to find group
 .Em operator
@@ -404,7 +417,7 @@ is written.
 Currently,
 .Xr physio 9
 slices all requests into chunks of 64 KB.  Therefore, it is
-impossible to use a larger tape blocksize, so
+impossible to use a larger output block size, so
 .Nm
 will prevent this from happening.
 .Pp