Basic partitioned access method - Revision history

82.109.66.148 at 12:34, 13 June 2019

2019-06-13T12:34:23Z

← Previous revision		Revision as of 12:34, 13 June 2019
Line 8:		Line 8:
	BPAM provides an [[application program interface]] (API) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.		BPAM provides an [[application program interface]] (API) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.

	The programmer specifies <code>DSORG=PO</code> in their[[Data Control Block]] (DCB) to indicate use of BPAM.		The programmer specifies <code>DSORG=PO</code> in their [[Data Control Block]] (DCB) to indicate use of BPAM.
	As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation proceeds [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a previous <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>		As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation proceeds [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a previous <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

82.109.66.148 at 12:34, 13 June 2019

2019-06-13T12:34:05Z

← Previous revision		Revision as of 12:34, 13 June 2019
Line 8:		Line 8:
	BPAM provides an [[application program interface]] (API) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.		BPAM provides an [[application program interface]] (API) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.

	The programmer specifies <code>DSORG=PO</code> in ~~his~~ [[Data Control Block]] (DCB) to indicate use of BPAM.		The programmer specifies <code>DSORG=PO</code> in their[[Data Control Block]] (DCB) to indicate use of BPAM.
	As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation proceeds [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a previous <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>		As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation proceeds [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a previous <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

Peter Flass: sp

2016-08-21T01:12:13Z

← Previous revision		Revision as of 01:12, 21 August 2016
Line 9:		Line 9:

	The programmer specifies <code>DSORG=PO</code> in his [[Data Control Block]] (DCB) to indicate use of BPAM.		The programmer specifies <code>DSORG=PO</code> in his [[Data Control Block]] (DCB) to indicate use of BPAM.
	As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation ~~procedes~~ [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>		As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation proceeds [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a previous <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

	==Load modules==		==Load modules==

Peter Flass: /* Application program interface */ note/point

2016-08-21T01:03:10Z

Application program interface: note/point

← Previous revision		Revision as of 01:03, 21 August 2016
Line 9:		Line 9:

	The programmer specifies <code>DSORG=PO</code> in his [[Data Control Block]] (DCB) to indicate use of BPAM.		The programmer specifies <code>DSORG=PO</code> in his [[Data Control Block]] (DCB) to indicate use of BPAM.
	As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>		As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref name=Macro>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>NOTE</code> macro instruction returns position of the last block read or written, and the <code>POINT</code> macro will reposition to the location identified by a <code>NOTE</code>.<ref name=Macro /> The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

	==Load modules==		==Load modules==

Peter Flass: DSORG=PO. Selete section "similar facilities which relates to PDSs and not to BPAM as an access method.

2016-08-20T06:49:32Z

DSORG=PO. Selete section "similar facilities which relates to PDSs and not to BPAM as an access method.

← Previous revision		Revision as of 06:49, 20 August 2016
Line 6:		Line 6:

	==Application program interface==		==Application program interface==
	BPAM provides an application program interface ([[API]]) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.		BPAM provides an [[application program interface]] (API) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.

			The programmer specifies <code>DSORG=PO</code> in his [[Data Control Block]] (DCB) to indicate use of BPAM.
	As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. <code>BLDL</code> ~~builds~~ a list of the addresses of members specified by the programmer for later use. <code>FIND</code> ~~will position~~ to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>		As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. The <code>BLDL</code> macro can be used to build a list of the addresses of members specified by the programmer for later use, if desired. <code>FIND</code> positions to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

	==Load modules==		==Load modules==
Line 14:		Line 15:

	The Linkage Editor organizes a load module in a specialized format consisting of alternating "text records" and "control/relocation dictionary records". This organization allows a load module to be completely loaded and relocated with one input/output operation by Program Fetch ([[Execute Channel Program\|EXCP]] on pre-MVS systems, or [[Start Input/Output\|STARTIO]] on MVS/370 and later systems).		The Linkage Editor organizes a load module in a specialized format consisting of alternating "text records" and "control/relocation dictionary records". This organization allows a load module to be completely loaded and relocated with one input/output operation by Program Fetch ([[Execute Channel Program\|EXCP]] on pre-MVS systems, or [[Start Input/Output\|STARTIO]] on MVS/370 and later systems).

	==Similar facilities==
	The closest parallel to partitioned datasets in other operating systems such as Unix or Windows is the [[static library]], such as produced by the [[ar (Unix)\|ar]] utility. In fact, the nomenclature for libraries in [[make (software)\|make]], <code>lib(member)</code>, is directly derived from [[OS/360]]. A PDS may be compared to a directory, that can contain only files, no subdirectories, and at the same time is physically stored in a single file. The need for libraries relates to the fact that mainframe operating systems (until very recently) did not have a hierarchical [[file system]].

	==References==		==References==

Peter Flass: /* Load modules */ delete "specialized"

2016-08-20T00:52:22Z

Load modules: delete "specialized"

← Previous revision		Revision as of 00:52, 20 August 2016
Line 11:		Line 11:

	==Load modules==		==Load modules==
	The operating system requires all executable programs to be stored in libraries because the member's directory entry contains additional attribute information specific to load modules. When used for storing load modules, directories also contain, among other data, the size of the load module and the address of the first "text record", which is different from the address of the first member data. Executable programs are written to libraries by the [[linkage editor]] and loaded into user-acquired storage by the Loader (an application program) or into system-acquired storage by Program Fetch (a ~~specialized~~ component of the OS [[Kernel (operating system)\|supervisor]]).		The operating system requires all executable programs to be stored in libraries because the member's directory entry contains additional attribute information specific to load modules. When used for storing load modules, directories also contain, among other data, the size of the load module and the address of the first "text record", which is different from the address of the first member data. Executable programs are written to libraries by the [[linkage editor]] and loaded into user-acquired storage by the Loader (an application program) or into system-acquired storage by Program Fetch (a component of the OS [[Kernel (operating system)\|supervisor]]).

	The Linkage Editor organizes a load module in a specialized format consisting of alternating "text records" and "control/relocation dictionary records". This organization allows a load module to be completely loaded and relocated with one input/output operation by Program Fetch ([[Execute Channel Program\|EXCP]] on pre-MVS systems, or [[Start Input/Output\|STARTIO]] on MVS/370 and later systems).		The Linkage Editor organizes a load module in a specialized format consisting of alternating "text records" and "control/relocation dictionary records". This organization allows a load module to be completely loaded and relocated with one input/output operation by Program Fetch ([[Execute Channel Program\|EXCP]] on pre-MVS systems, or [[Start Input/Output\|STARTIO]] on MVS/370 and later systems).

Peter Flass: add API section head and move paragraph

2016-08-20T00:48:42Z

add API section head and move paragraph

← Previous revision		Revision as of 00:48, 20 August 2016
Line 3:		Line 3:
	A PDS consists of members (internally identical to [[data set (IBM mainframe)\|sequential data sets]]), registered in a list called the ''directory''. The combination of members and directory is a single dataset on disk. The directory contains a list of member's names (8 characters, padded on the right with blanks, as required) and member's addresses. Addresses are relative to the start of the dataset in order to allow the PDS to be moved to a different disk location.		A PDS consists of members (internally identical to [[data set (IBM mainframe)\|sequential data sets]]), registered in a list called the ''directory''. The combination of members and directory is a single dataset on disk. The directory contains a list of member's names (8 characters, padded on the right with blanks, as required) and member's addresses. Addresses are relative to the start of the dataset in order to allow the PDS to be moved to a different disk location.

		⚫	Partitioned datasets can store any type of data, but they are often used to store [[executable\|executable programs]], or ''load modules'', sometimes called binaries in other systems. Other uses include system assembler [[Macro (computer science)\|macro]] definitions, [[Job Control Language\|job control]] procedures, and program source code.
⚫	BPAM provides an application program interface ([[API]]) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement. As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. <code>BLDL</code> builds a list of the addresses of members specified by the programmer for later use. <code>FIND</code> will position to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

			==Application program interface==
⚫	Partitioned datasets can store any type of data, but they are often used to store [[executable\|executable programs]], or ''load modules'', sometimes called binaries in other systems. Other uses ~~for libraries~~ include system assembler [[Macro (computer science)\|macro]] definitions, [[Job Control Language\|job control]] procedures, and program source code.
			BPAM provides an application program interface ([[API]]) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.

		⚫	As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. <code>BLDL</code> builds a list of the addresses of members specified by the programmer for later use. <code>FIND</code> will position to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>

	==Load modules==		==Load modules==

Peter Flass: description of basic access method, BPAM macros

2016-08-20T00:33:55Z

description of basic access method, BPAM macros

← Previous revision		Revision as of 00:33, 20 August 2016
Line 3:		Line 3:
	A PDS consists of members (internally identical to [[data set (IBM mainframe)\|sequential data sets]]), registered in a list called the ''directory''. The combination of members and directory is a single dataset on disk. The directory contains a list of member's names (8 characters, padded on the right with blanks, as required) and member's addresses. Addresses are relative to the start of the dataset in order to allow the PDS to be moved to a different disk location.		A PDS consists of members (internally identical to [[data set (IBM mainframe)\|sequential data sets]]), registered in a list called the ''directory''. The combination of members and directory is a single dataset on disk. The directory contains a list of member's names (8 characters, padded on the right with blanks, as required) and member's addresses. Addresses are relative to the start of the dataset in order to allow the PDS to be moved to a different disk location.

			BPAM provides an application program interface ([[API]]) to allow programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement. As a ''basic'' access method BPAM reads and writes member data in [[Block (data storage)\|blocks]] and the I/O operation procedes [[Asynchronous I/O\|asynchronously]] and must be tested for completion using the <code>CHECK</code> macro.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Macro Instructions\|date=June 1973\|page=157\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3794-1_OS_Data_Management_Macro_Instructions_Rel_21.7_Jun73.pdf\|accessdate=August 19, 2016}}</ref> BPAM uses the standard system macros <code>OPEN</code>, <code>CLOSE</code>, <code>READ</code>, <code>WRITE</code>,and <code>CHECK</code>. <code>BLDL</code> builds a list of the addresses of members specified by the programmer for later use. <code>FIND</code> will position to a single member, specified by name, which requires a directory lookup on disk, or by address previously retrieved by <code>BLDL</code>. The <code>STOW</code> macro is used to update the directory when a member is added, deleted, changed (including renamed), or replaced.<ref>{{cite book\|last1=IBM Corporation\|title=OS Data Management Services Guide\|date=July 1973\|pages=75–85\|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/360/os/R21.7_Apr73/GC26-3746-2_OS_Data_Management_Services_Guide_Rel_21.7_Jul73.pdf\|accessdate=August 19, 2016}}</ref>
⚫	Partitioned datasets can store any type of data, but they are often used to store [[executable\|executable programs]], or ''load modules'', sometimes called binaries in other systems. Other uses for libraries include system assembler [[Macro (computer science)\|macro]] definitions, [[Job Control Language\|job control]] procedures, and program source code. BPAM provides an application program interface [[API]] to programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.

		⚫	Partitioned datasets can store any type of data, but they are often used to store [[executable\|executable programs]], or ''load modules'', sometimes called binaries in other systems. Other uses for libraries include system assembler [[Macro (computer science)\|macro]] definitions, [[Job Control Language\|job control]] procedures, and program source code.

	==Load modules==		==Load modules==

Peter Flass: /* Similar facilities */ code

2016-08-19T23:59:27Z

Similar facilities: code

← Previous revision		Revision as of 23:59, 19 August 2016
Line 11:		Line 11:

	==Similar facilities==		==Similar facilities==
	The closest parallel to partitioned datasets in other operating systems such as Unix or Windows is the [[static library]], such as produced by the [[ar (Unix)\|ar]] utility. In fact, the nomenclature for libraries in [[make (software)\|make]], ~~'''~~lib(member)~~'''~~, is directly derived from [[OS/360]]. It may be compared to a directory, that can contain only files, no subdirectories, and at the same time ~~that~~ is physically stored in a single file. The need for libraries relates to the fact that mainframe operating systems (until very recently) did not have a hierarchical [[file system]].		The closest parallel to partitioned datasets in other operating systems such as Unix or Windows is the [[static library]], such as produced by the [[ar (Unix)\|ar]] utility. In fact, the nomenclature for libraries in [[make (software)\|make]], <code>lib(member)</code>, is directly derived from [[OS/360]]. A PDS may be compared to a directory, that can contain only files, no subdirectories, and at the same time is physically stored in a single file. The need for libraries relates to the fact that mainframe operating systems (until very recently) did not have a hierarchical [[file system]].

	==References==		==References==

Peter Flass: cleanup

2016-08-19T23:56:22Z

cleanup

← Previous revision		Revision as of 23:56, 19 August 2016
Line 3:		Line 3:
	A PDS consists of members (internally identical to [[data set (IBM mainframe)\|sequential data sets]]), registered in a list called the ''directory''. The combination of members and directory is a single dataset on disk. The directory contains a list of member's names (8 characters, padded on the right with blanks, as required) and member's addresses. Addresses are relative to the start of the dataset in order to allow the PDS to be moved to a different disk location.		A PDS consists of members (internally identical to [[data set (IBM mainframe)\|sequential data sets]]), registered in a list called the ''directory''. The combination of members and directory is a single dataset on disk. The directory contains a list of member's names (8 characters, padded on the right with blanks, as required) and member's addresses. Addresses are relative to the start of the dataset in order to allow the PDS to be moved to a different disk location.

	Partitioned datasets can store any type of data, but they are often used to store [[executable\|executable programs]],h or ''load modules'', sometimes called binaries in other systems. Other uses for libraries include system assembler [[Macro (computer science)\|macro]] definitions, [[job control]] procedures, and program source code. BPAM provides an [[API]] to programmers to access libraries directly. The BPAM [[API]] is ~~fairly~~ similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. ~~PDS~~ members can also be ~~procesed~~ using sequential access methods by specifying the member name on the job control ''DD'' statement.		Partitioned datasets can store any type of data, but they are often used to store [[executable\|executable programs]], or ''load modules'', sometimes called binaries in other systems. Other uses for libraries include system assembler [[Macro (computer science)\|macro]] definitions, [[Job Control Language\|job control]] procedures, and program source code. BPAM provides an application program interface [[API]] to programmers to access libraries directly. The BPAM API is similar to [[basic sequential access method]] (BSAM), but it adds functionality to process directories. Individual members of a PDS can also be processed using sequential access methods by specifying the member name on the job control ''DD'' statement.

	==Load modules==		==Load modules==
	The operating system requires all executable programs to be stored in libraries because the member's directory entry contains additional attribute information specific to load modules. When used for storing load modules, directories also contain, ~~amongst~~ other data, the size of the load module and the address of the first "text record", which is different from the address of the first member data. Executable programs are written to libraries by the [[linkage editor]] and loaded into user-acquired storage by the Loader (an application program) or into system-acquired storage by Program Fetch (a specialized component of the OS [[Kernel (operating system)\|supervisor]]).		The operating system requires all executable programs to be stored in libraries because the member's directory entry contains additional attribute information specific to load modules. When used for storing load modules, directories also contain, among other data, the size of the load module and the address of the first "text record", which is different from the address of the first member data. Executable programs are written to libraries by the [[linkage editor]] and loaded into user-acquired storage by the Loader (an application program) or into system-acquired storage by Program Fetch (a specialized component of the OS [[Kernel (operating system)\|supervisor]]).

	The Linkage Editor organizes a load module in a specialized format consisting of alternating "text records" and "control/relocation dictionary records". This organization allows a load module to be completely loaded and relocated with one EXCP (on pre-MVS ~~instances~~ of ~~the OS) and with one~~ STARTIO (on MVS/370 and later ~~instances of the OS~~) ~~by Program Fetch~~.		The Linkage Editor organizes a load module in a specialized format consisting of alternating "text records" and "control/relocation dictionary records". This organization allows a load module to be completely loaded and relocated with one input/output operation by Program Fetch ([[Execute Channel Program\|EXCP]] on pre-MVS systems, or [[Start Input/Output\|STARTIO]] on MVS/370 and later systems).

	==Similar facilities==		==Similar facilities==