What is mean by SID in SAP?

SID

        Each R/3 installation (SAP system) of a database server and several app servers running the application logic is uniquely identified by a single SID (SAP System Identification), SAP system name or SAP SID can be of maximum 3 alphanumeric characters and its first character must be an alphabet such as D11,SDK, K56, etc.

There some Reserved SIDs in SAP We unable use this SIDs.

No.	SID	Status	Description
1	ADD	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
2	ADM	Prevented by SWPM.	SQL keyword, when used as SAPSID queries could break.
3	ALL	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Reserved SQL keyword, when used as SAPSID or DBSID queries could break.
4	AMD	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID.
5	AND	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
6	ANY	Prevented by SWPM. Listed as reserved since SAP NetWeaver 7.0 SR2.	Reserved SQL keyword, when used as SAPSID or DBSID queries could break.
7	ARE	Prevented by SWPM. Listed as reserved since 4.6C SR2.	ODBC reserved keyword, when used as SAPSID queries could break.
8	ASC	Prevented by SWPM. Listed as reserved since SAP NetWeaver 7.0 SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
9	AUX	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. 'AUX' is the Windows Pseudofile for Auxilary Device.
10	AVG	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	ODBC reserved keyword, when used as SAPSID queries could break.
11	BIN	Prevented by SWPM SP06 and later. Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server ABAP. Requested by SUM 1.0 SP9 or lower with problems to distinguish between 'bin' and 'BIN' on Windows and i5.
12	BIT	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	ODBC reserved keyword, when used as SAPSID or DBSID queries could break.
13	CDC	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Reserved keyword on MS SQL Server, can lead to data loss when used as SAPSID or DBSID.
14	COM	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID. 'COM' is the Windows Pseudofile for a communication port.
15	CON	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. 'CON' is the Windows Pseudofile for Console input/output.

16	DAA	Prevented by SWPM 1.0 SP06 and later, for non Diagnostics Agent installations. Used by SAP Solution Manager Diagnostics Agent	In case 'DAA' is already used, the values 'DA1' … 'DA9' are tried and offered in the installer UI when installing an SAP Solution Manager Diagnostics Agent.
17	DBA	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
18	DBM	Prevented by SWPM for DB2 for Windows and Unix.	Cannot be used as DBSID.
19	DBO	Prevented by SWPM. Listed as reserved since SWPM 1.0 SP6.	Reserved keyword/schema on SQL Server, when used as SAPSID or DBSID queries could break.
20	DTD	Prevented by SWPM SP06 and later Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server Java. Requested by SUM 1.0 for Application server Java with problems to distinguish between 'dtd' and 'DTD' on Windows and i5.
21	END	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Reserved SQL keyword, when used as SAPSID or DBSID queries could break.
22	EPS	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
23	EXE	Prevented by SWPM SP06 and later Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server ABAP or Java. Requested by SUM 1.0 SP9 or lower with problems to distinguish between 'exe' and 'EXE' on Windows and i5.
24	FOR	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
25	GET	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID.
26	GID	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
27	IBM	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
28	INT	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
29	KEY	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
30	LOG	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID. Should not be used for SAP application server ABAP or Java. Requested by SUM 1.0 SP9 and lower with problems to distinguish between 'log' and 'LOG' on Windows and i5.
31	LPT	Prevented by SWPM. Listed as	Cannot be used as SAPSID or DBSID.

 

		reserved since ERP 6.0 EHP5.	'LPT' is the Windows Pseudofile for a parallel printer port.
32	LIB	Prevented by SWPM SP06 and later Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server Java. Requested by SUM 1.0 SP9 and lower with problems to distinguish between 'lib' and 'LIB' on Windows and i5.
33	MAP	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	ODBC reserved keyword, when used as SAPSID or DBSID queries could break.
34	MAX	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. SQL Server function.
35	MEM	Prevented by SWPM SP06 and later Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server ABAP. Requested by SUM 1.0 SP9 with problems to distinguish between 'mem' and 'MEM' on Windows and i5.
36	MIG	Prevented by SWPM SP06 and later Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server ABAP. Requested by SUM 1.0 SP9 and lower with problems to distinguish between 'mig' and 'MIG' on Windows and i5.
37	MIN	Prevented by SWPM.	ODBC reserved keyword, when used as SAPSID or DBSID queries could break.
38	MON	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Reserved future keyword, when used as SAPSID or DBSID queries could break in future.
39	NIX	Prevented by SWPM, Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID. Reserved for internal ABAP transport tools (tp) related to cofiles read error
40	NOT	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
41	NUL	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. 'NUL' is the Windows Pseudofile for NULL device.
42	OFF	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
43	OLD	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. Reserved future keyword, when used as SAPSID or DBSID queries could break in future.
44	OMS	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
45	OUT	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. Reserved future keyword, when used as SAPSID queries could break in future.

 

46	PAD	Prevented by SWPM for MSSQL. Listed as reserved since ERP 6.0 EHP5.	MS SQL Server reserved keyword, when used as SAPSID or DBSID queries could break
47	PRN	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Cannot be used as SAPSID or DBSID. 'PRN' is the Windows Pseudofile for Printer output.
48	RAW	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
49	REF	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	Reserved future keyword, when used as SAPSID or DBSID queries could break in future.
50	ROW	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Reserved future keyword, when used as SAPSID or DBSID queries could break in future.
51	SAP	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID. Requested from ABAP transport tools (tp) related to anonymization. Furthermore sapadm (<sid>adm) is the operating system owner of the SAP Hostagent executables.
52	SET	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SQL keyword, when used as SAPSID or DBSID queries could break.
53	SGA	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
54	SHG	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
55	SID	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
56	SQL	Prevented by SWPM. Listed as reserved since 4.6C SR2.	ODBC reserved keyword, when used as SAPSID or DBSID queries could break.
57	SUM	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	ODBC reserved keyword, when used as SAPSID or DBSID queries could break.
58	SYS	Prevented by SWPM. Listed as reserved since 4.6C SR2.	SAP internal identifier. Cannot be used as SAPSID or DBSID.
59	TMP	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as SAPSID or DBSID.
60	TOP	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	SQL keyword, when used as SAPSID or DBSID queries could break.
61	TRC	Prevented by SWPM SP06 and later Listed as reserved by SUM on i5 and Windows.	Should not be used for SAP application server ABAP or Java. Requested by SUM 1.0 SP9 and lower with problems to distinguish between 'trc' and 'TRC' on Windows and i5.
62	UID	Prevented by SWPM. Listed as	Cannot be used as SAPSID or DBSID.

 

		reserved since 4.6C SR2.	Should not be used for SAP application server ABAP or Java.
63	USE	Prevented by SWPM. Listed as reserved since ERP 6.0 EHP5.	MS SQL Server reserved keyword, when used as SAPSID or DBSID queries could break
64	USR	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Cannot be used as DBSID.
65	VAR	Prevented by SWPM. Listed as reserved since 4.6C SR2.	Should not be used as SAPSID for SAP application server ABAP. Requested by SUM 1.0 SP9 and lower with problems to distinguish between 'var' and 'VAR' on Windows and i5.