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When any COBOL-DB2 program is pre-compiled, the current timestamp is inserted in the DBRM and if the DBRM is binded to a package then the timestamp is further copied to a package. Similarly, the timestamp is also inserted in the load module during the compilation process.When any COBOL-DB2 program is executed, the system matches the timestamp of the load module with that in the DBRM/package, if there is mismatch then the program fails.In case DBRM directly binds to a plan, we need to bind both the plans - PLANA and PLANB again even if only the subprogram has gone through ... Read More
A DBRM can be directly bound to a plan or we can first bind DBRM into a package and then bind that package into PLAN.In case DBRM binds to a plan directly, if there is some change in the source code, the new DBRM has to be generated and then we have to bind the entire plan again. Since, plan contains multiple DBRMs, the system will process all the DBRMs again in order to bind that plan (even if the other DBRMs have not gone through any changes). This process takes a lot of resources like memory, processor and valuable ... Read More
A DBRM is a DB2 object which is generated from the pre-compilation of the source code. It contains all the SQL statements/queries of the source code. DBRM could not be executed directly due to its format, hence it is binded into a plan first. There can be multiple DBRM which can be binded in a single plan.Whenever there is a source code change, corresponding DBRM has to be generated again with changed SQL statements/queries. Then the entire plan (which contains the old DBRM) has to be bound again.Using the below JCL step we can BIND a DBRM directly into a ... Read More
Precompilation is the process through which the SQL statements used in the COBOL-DB2 program are replaced by appropriate COBOL calls. The precompilation is necessary before the actual compilation because the COBOL compiler cannot recognize the DB2 SQL statements and will throw errors due to them.DB2 utility DSNHPC is used for the precompilation. The inputs to the precompilation JCL step are DCLGEN (in SYSLIB) for the respective tables which are used in COBOL-DB2 program and COBOL-DB2 source program (in SYSIN).//STEP010 EXEC PGM=IKJEFT01 //SYSIN DD DSN=DIS.TEST.COBOL(PSNEW2), DISP=SHR //SYSLIB DD DSN=DIS.TEST.DCLGEN(PSDC2), DISP=SHR //DBRMLIB DD DSN=DIS.TEST.DBRMLIB(PSNEW2), DISP=SHR //SYSCIN DD DSN=DIS.TEST.COBL(PSCOB2), DISP=(NEW, CATLG, DEL), SPACE=(20, ... Read More
The package is a database object which contains the SQL statements from DBRM in a DB2-optimized form.The collection is a group of packages using which we can segregate the DB2 packages belonging to the different applications. For example, in a production environment for a Telecom company, we can have different collections for order handling, billing and customer service.The package or group of packages (collections) are binded into a plan. A plan is an executable object which contains the DB2 access paths of all the SQL queries within it. We can bind a package into a plan directly or we can ... Read More
The COBOL-DB2 program can be executed with the help of IKJEFT01. The IKJEFT01 is an inbuilt mainframe utility that allows us to run z/OS TSO commands via Job control language(JCL). If we want to execute a COBOL-DB2 program PROGA of plan PLANA we must give a JCL step as below.//STEP010 EXEC PGM=IKJEFT01 //STEPLIB DD DSN=DIS.TEST.LOADLIB, DISP=SHR //SYSOUT DD SYSOUT=* //SYSTSIN DD * DSN SYSTEM(TB3) RUN PROGRAM (PROGA) PLAN(PLANA) END /*In the above JCL step, we have first used IKJEFT01 utility to call the COBOL-DB2 program. The loadlib path for the program PROGA is given in STEPLIB i.e. DIS.TEST.LOADLIB and the ... Read More
Radio Frequency Identification (RFID) is the application of radio waves to read and capture information stored on tags affixed to objects. RFID readers are installed at tracking points and can read information from tags when they come into range, which can be of several feet radius. A tag need not be within direct line-of-sight of the reader to be tracked. RFID is used to check identities and track inventory, assets and people. RFID tags can be attached to a variety of objects like cash, clothing, baggage, parcels, and even implanted in animals and people.Working PrincipleThere are two parts in a ... Read More
The Bluetooth network technology connects mobile devices wirelessly using short-wavelength, ultra-high frequency (UHF) radio waves over a short range to form a personal area network (PAN). Data is transferred between the Bluetooth devices as data frames. Two basic frame formats are defined, for transmitting data at basic data rate and for transmitting data at enhanced data rate.Bluetooth Frame Format with Basic Data RateA Bluetooth frame with basic rate has three parts, access code, header and data as shown in the following diagram−The various fields are−Access Code− A 72-bit field containing synchronization bits to identify the master.Header− A 54-bit field containing ... Read More
Bluetooth link layers define two types of data links, Asynchronous Connection-Less (ACL) Link, being one of them. It is the type of link used for transmission of general data packets using Bluetooth connection. ACL is a point – to – multipoint link used for irregular traffic between a master device and one or more slave devices.Features of Bluetooth ACL linksACL is a packet oriented link, i.e. the link establishes a packet – switched network.ACL is used for transmission of data traffic which are delivered at irregular intervals, where maintaining data integrity is more important than the time latency.Both symmetric and ... Read More
Bluetooth link layers define two types of data links, Synchronous Connection Oriented (SCO) link, being one of them. SCO is a symmetric, point-to-point link between the master device and the slave device connected via Bluetooth.Features of Bluetooth SCO linksIn SCO, a dedicated, point-to-point link is established between the master device and the slave device before communication starts.SCO is a symmetric link, i.e. fixed slots are allocated for each direction.Since fixed slots are reserved, SCO provides a circuit switched connection.SCO radio links are used for time critical data transfer, particularly for voice data.Both the master and the slave device transmit encoded ... Read More