Refer to I/O (not IO), ID (not id), and "an rsync" (not "a rsync").

rsyncd.conf.yo

@@ -93,7 +93,7 @@ useful on systems (such as AIX) where syslog() doesn't work for
 chrooted programs.
 
 dit(bf(pid file)) The "pid file" option tells the rsync daemon to write
-its process id to that file.
+its process ID to that file.
 
 dit(bf(syslog facility)) The "syslog facility" option allows you to
 specify the syslog facility name to use when logging messages from the
@@ -172,13 +172,13 @@ listed when the client asks for a listing of available modules. By
 setting this to false you can create hidden modules. The default is
 for modules to be listable.
 
-dit(bf(uid)) The "uid" option specifies the user name or user id that
+dit(bf(uid)) The "uid" option specifies the user name or user ID that
 file transfers to and from that module should take place as when the daemon
 was run as root. In combination with the "gid" option this determines what
 file permissions are available. The default is uid -2, which is normally
 the user "nobody".
 
-dit(bf(gid)) The "gid" option specifies the group name or group id that
+dit(bf(gid)) The "gid" option specifies the group name or group ID that
 file transfers to and from that module should take place as when the daemon
 was run as root. This complements the "uid" option. The default is gid -2,
 which is normally the group "nobody".
@@ -237,7 +237,7 @@ connect without a password (this is called "anonymous rsync").
 See also the bf(CONNECTING TO AN RSYNC SERVER OVER A REMOTE SHELL
 PROGRAM) section in rsync(1) for information on how handle an
 rsyncd.conf-level username that differs from the remote-shell-level
-username when using a remote shell to connect to a rsync server.
+username when using a remote shell to connect to an rsync server.
 
 dit(bf(secrets file)) The "secrets file" option specifies the name of
 a file that contains the username:password pairs used for
@@ -255,7 +255,7 @@ by "other"; see "strict modes".
 
 dit(bf(strict modes)) The "strict modes" option determines whether or not 
 the permissions on the secrets file will be checked.  If "strict modes" is
-true, then the secrets file must not be readable by any user id other
+true, then the secrets file must not be readable by any user ID other
 than the one that the rsync daemon is running under.  If "strict modes" is
 false, the check is not performed.  The default is true.  This option
 was added to accommodate rsync running on the Windows operating system.
@@ -314,10 +314,10 @@ rejected. See the "hosts allow" option for more information.
 The default is no "hosts deny" option, which means all hosts can connect.
 
 dit(bf(ignore errors)) The "ignore errors" option tells rsyncd to
-ignore IO errors on the server when deciding whether to run the delete
+ignore I/O errors on the server when deciding whether to run the delete
 phase of the transfer. Normally rsync skips the --delete step if any
-IO errors have occurred in order to prevent disasterous deletion due
-to a temporary resource shortage or other IO error. In some cases this
+I/O errors have occurred in order to prevent disasterous deletion due
+to a temporary resource shortage or other I/O error. In some cases this
 test is counter productive so you can use this option to turn off this
 behaviour. 
 
@@ -342,7 +342,7 @@ itemize(
   it() %h for the remote host name
   it() %a for the remote IP address
   it() %l for the length of the file in bytes
-  it() %p for the process id of this rsync session
+  it() %p for the process ID of this rsync session
   it() %o for the operation, which is either "send" or "recv"
   it() %f for the filename
   it() %P for the module path
@@ -361,7 +361,7 @@ A perl script called rsyncstats to summarize this format is included
 in the rsync source code distribution.
 
 dit(bf(timeout)) The "timeout" option allows you to override the
-clients choice for IO timeout for this module. Using this option you
+clients choice for I/O timeout for this module. Using this option you
 can ensure that rsync won't wait on a dead client forever. The timeout
 is specified in seconds. A value of zero means no timeout and is the
 default. A good choice for anonymous rsync servers may be 600 (giving
@@ -423,7 +423,7 @@ where command would be
 quote(rsync --server --daemon .)
 
 NOTE: rsync's argument parsing expects the trailing ".", so make sure
-that it's there.  If you want to use a rsyncd.conf(5)-style
+that it's there.  If you want to use an rsyncd.conf(5)-style
 configuration file other than the default, you can added a
 --config option to the em(command):