Find ASM Home

Question

Hi,
My question is :
To find the ORACLE HOME we use the "echo $ORACLE_HOME" and to find the CRS HOME we use the "echo $ORA_CRS_HOME"; In the same way, What variable i have to use to find ASM HOME ?
$ ps -ef |grep smon
oracle 7416 1 0 Apr08 ? 00:00:00 asm_smon_+ASM1
oracle 8218 1 0 Apr08 ? 00:06:20 ora_smon_ractest1
oracle 28210 15182 0 15:23 pts/0 00:00:00 grep smon
$ echo $ORACLE_HOME
/u01/app/oracle/product/10.2.0/db_1
$ echo $ORACLE_SID
ractest1
$ export ORACLE_SID=+ASM1
$ echo $ORACLE_SID
+ASM1
$ echo $ASM_HOME >>>>>>>>>>>>>>>>>>>>>>>>
$
$ sqlplus "/as sysdba"
SQL*Plus: Release 10.2.0.3.0 - Production on Sat Jul 3 15:25:11 2010
Copyright (c) 1982, 2006, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options
SQL> select instance_name from v$instance;
INSTANCE_NAME
+ASM1
$ cat /etc/oratab
+ASM1:/u01/app/oracle/product/10.2.0/db_1:N
ractest:/u01/app/oracle/product/10.2.0/db_1:N
------------------------------------

Answer 1

First of all ASM_HOME ora ORA_ASM_HOME - there are no conventions or requirements by Oracle to use this variables.
When saying "oracle home" we do not mean the home directory for 'database' type instance or the home for 'asm' type instance. There is just one term, Oracle Home - which means oracle software installation directory - not regarding which type of instance is run from this directory(i.e. from oracle home).
So, for your ASM instance also you will have a term "oracle home" which means the home directory of database binaries and other files.
Regarding to your configuration, you yourself answered to your question in your first post(question). your database and asm instances both share the same oracle home, which is shown via entries in your oratab file
$ cat /etc/oratab
+ASM1:/u01/app/oracle/product/10.2.0/db_1:N
ractest:/u01/app/oracle/product/10.2.0/db_1:N