Update the diskless(8) documentation to indicate that the use of the

kernel BOOTP options is *not* required if the boot loader can pass
network configuration information to the kernel using the kernel
environment.  As such, PXE doesn't require them.  However, the NFS
options are required in the kernel (previously not documented).

Tripped over by:	des

1 files changed, 24 insertions, 7 deletions

diff --git a/share/man/man8/diskless.8 b/share/man/man8/diskless.8
index ea59ead791c3..be6fe41ff6da 100644
--- a/share/man/man8/diskless.8
+++ b/share/man/man8/diskless.8
@@ -1,5 +1,5 @@
 .\" Copyright (c) 1994 Gordon W. Ross, Theo de Raadt
-.\" Updated by Luigi Rizzo
+.\" Updated by Luigi Rizzo, Robert Watson
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 23, 2002
+.Dd January 10, 2004
 .Dt DISKLESS 8
 .Os
 .Sh NAME
@@ -129,13 +129,18 @@ make clean; make; make install
 cp /boot/pxeboot /tftpdir/
 .Ed
 .Pp
-In phase 3, the kernel again uses
+In phase 3, the kernel acquires IP networking configuration in one
+of two ways, and then proceeds to mount the root file system and start
+operation.
+If the phase 2 loader supporst passing network configuration to the
+kernel using the kernel environment, then the kernel will configure
+the network interface using that information.
+Otherwise, it must use
 .Tn DHCP
 or
 .Tn BOOTP
 to acquire
-configuration information, and proceeds to mount the
-root file system and start operation.
+configuration information.
 The boot
 scripts recognize a
 .Nm
@@ -401,13 +406,25 @@ clients, which will be loaded using
 .Tn NFS
 or
 .Tn TFTP ,
-should be built with at least the following options:
+must include support for the NFS client:
+.Pp
+.D1 Cd "options NFSCLIENT"
+.D1 Cd "options NFS_ROOT"
+.Pp
+If you are using a boot mechanism that does not pass network configuration
+to the kernel using the kernel environment, you will also need to include
+the following options:
 .Pp
 .D1 Cd "options BOOTP"
 .D1 Cd "options BOOTP_NFSROOT"
 .D1 Cd "options BOOTP_COMPAT"
 .Pp
-In the devices section add:
+NOTE: The PXE environment does not require these uptions.
+.Pp
+The diskless booting environment relies on memory-backed file systems to
+support temporary local storage in the event that the root file system
+is mounted read-only; as such, it is necessary to add the following
+to the device section of the kernel configuration:
 .Pp
 .D1 Cd "device md"
 .Pp