diff --git a/require-ess/tools/driver.makefile b/require-ess/tools/driver.makefile
index fa6a93dfa0d23851ea2e9be9a9e786c9d06abe35..1c792be0bb6d14cb4dd6f7f8d6ddbf3bd718bcde 100644
--- a/require-ess/tools/driver.makefile
+++ b/require-ess/tools/driver.makefile
@@ -59,9 +59,8 @@ MAKEHOME:=$(dir $(lastword ${MAKEFILE_LIST}))
 USERMAKEFILE:=$(lastword $(filter-out $(lastword ${MAKEFILE_LIST}), ${MAKEFILE_LIST}))
 
 
-##---## In E3, We only use ONE EPICS_BASE in order to COMPILE A MODULE
-##---##
-##---## In E3,  EPICS_LOCATION is the EPICS BASE  /testing/epics/base-MAJ.MIN.REV[.PATCH]
+##---## In E3, We only use one version of EPICS base when compiling modules.
+##---## EPICS_LOCATION is (by default) /epics/base-${EPICSVERSION}
 EPICS_LOCATION =
 EPICS_BASE=${EPICS_LOCATION}
 CONFIG=${EPICS_BASE}/configure
@@ -96,7 +95,7 @@ RM = rm -f
 CP = cp
 MKDIR = mkdir -p -m 775
 
-# This is to allow for build numbers in recognized versions. First regex is for grep, second for sed.
+# This is to allow for build numbers in recognized versions.
 VERSIONREGEX = [0-9]+\.[0-9]+\.[0-9]+(\+[0-9]+)?
 
 # Some generated file names:
@@ -208,13 +207,11 @@ COMMON_DIR = O.${EPICSVERSION}_Common
 
 ifndef T_A
 ## RUN 1
-# Target achitecture not yet defined
-# but EPICSVERSION is already known.
+# Target achitecture not yet defined, but EPICSVERSION is already known.
 # Still in source directory.
 
-# Look for sources etc.
-# Select target architectures to build.
-# Export everything for third run:
+# Look for sources etc., and select target architectures to build.
+# Export everything for second run:
 
 AUTOSRCS := $(filter-out ~%,$(wildcard *.c *.cc *.cpp *.st *.stt *.gt))
 SRCS = $(if ${SOURCES},$(filter-out -none-,${SOURCES}),${AUTOSRCS})
@@ -320,7 +317,7 @@ else # T_A
 ifeq ($(filter O.%,$(notdir ${CURDIR})),)
 ## RUN 2
 # Target architecture defined.
-# Still in source directory, third run.
+# Still in source directory, second run.
 
 # Add sources for specific epics types or architectures.
 ARCH_PARTS = ${T_A} $(subst -, ,${T_A}) ${OS_CLASS}
@@ -455,7 +452,7 @@ export ${PRJ}_GIT_STATUS
 
 else # in O.*
 ## RUN 3
-# In O.* directory.
+# In build directory.
 
 # Add macros like USR_CFLAGS_Linux.
 EXTENDED_VARS=INCLUDES CFLAGS CXXFLAGS CPPFLAGS CODE_CXXFLAGS LDFLAGS