Top 100 CICS Interview Questions
1. What is CICS?
CICS (Customer Information Control System) is a transaction server that runs primarily on IBM mainframe systems under z/OS and z/VSE.
CICS is a transaction manager designed for rapid, high-volume online processing. This processing is mostly interactive (screen-oriented), but background transactions are possible.
While CICS has its highest profile among financial institutions such as banks and insurance companies, over 90 percent of Fortune 500 companies are reported to rely on CICS (running on z/OS) for their core business functions, beside many governments. CICS is used in bank-teller applications, ATM systems, industrial production control systems, insurance applications and many other types of interactive application.
Recent CICS Transaction Server enhancements include support for Web services and Enterprise Java Beans (EJBs). IBM began shipping the latest release, CICS Transaction Server – Version 3.2, in June of 2007.
2. Kindly specify the PIC clause for the following:
Any BLL Cell, Data type of Length Option field, HHMMSS type of data fields?
Any BLL Cell -S9(8) COMP
Data type of length Option field – S9(4) COMP
HHMMSS type of data fields – S9(7) COMP 3
3. List the sequence of steps used to achieve Modiication in Skip Sequential Mode?
List the sequence of steps used to achieve “Modiication in Skip Sequential Mode”.
I. READNEXT command
II. Issue the ENDBR command
II. Issue the READ command with UDATE option.
IV. Manipulate the record ( DELETE or REWRITE command)
V. Issue START command
VI. Isusue two READNEXT commands (One for dummy skip)
VII. Go to step two.
4. What are the commands used to gain exclusive control over a resource?
What are the commands used to gain
exclusive control over a resource
(for Ex a Temporary storage queue.)?
EXEC CICS ENQ EXEC CICS DEQ
RESOURCE(QID) RESOURCE(QID)
END-EXEC END-EXEC
5. Mention the 5 fields available in the symbolic map for every NAMED field in the DFHMDI macro? Give a brief description of these fields (Not exceeding a line).?
FIELD+L – Return the length of text entered (or for dymanic cursor positioning)
FIELD+F – Return X(80) if data entered but erased.
FIELD+A – Used for attributes reading and setting
FIELD+I – Used for reading the text entered while receiving the map.
FIELD+O – Used for sending information on to the MAP.
6. How do you intitiate another transaction?
The transaction initiated should be in a position to retrieve information pertaining to which transaction has initiated it and from which terminal. (Code the required CICS commands)
EXEC CICS START
INTERVAL(hhmmss)/TIME(hhmmss)
TRANSID(‘TRAN’)
TERMID(‘TRM1)
FROM(data-area)
LENGTH(data-value)
RTRANSID(EIBTRNID)
RTERMID(EIBTRMID)
END-EXEC
EXEC CICS RETRIEVE
INTO(data-area)
LENGTH(data-value)
RTRANSID(data-name)
RTERMID(data-name)
END-EXEC
7. What is the CICS command used to access current date and time?
ASKTIME.
8. How do you terminate an already issued DELAY command?
EXEC CICS CANCEL
REQID(id)
END-EXEC
9. Which option of the PCT entry is used to specify the PF key to be pressed for initiating a transaction?
TASKREQ=PF1
10. Mention the option used in the CICS READ command to gain accessibility directly to the file I/O area. (Assume COBOL-II).?
SET(ADDRESS OF LINKAGE-AREA).
11. How do you establish a starting position in a browse operation?
EXEC CICS STARTBR —- END-EXEC.
12. What is the CICS command that gives the length of TWA area?
EXEC CICS ASSIGN
TWALENG(data-value)
END-EXEC.
13. How do you set the MDT option to ON status, even if data is not entered?
Mention FSET option in DFHMDF or set it dynamically in the program using FIELD+A sttribute field.
14. How do you dynamically set the CURSOR position to a specific field?
MOVE-1 to FIELD + L field. Mention CURSOR option in the SEND command.
15. Specify the CICS command used to read a VSAM record starting with prefix F. Code all the relevant options?
EXEC CICS READ
DATASET(‘FILENAME’)
INTO(data-area)
RIDFLD(data-area)
KEYLENGTH(1)
GENERIC
LENGTH(WK-LEN)
END-EXEC.
16. Which command is used to release a record on which exclusive control is gained?
EXEC CICS UNLOCK END-EXEC.
17. What is the option specified in the read operation to gain multiple concurrent operations on the same dataset?
REQID(value)
18. What are the attribute values of Skipper and Stopper fields?
ASKIP. PROT.
19. Specify CICS transaction initiation process. ( From the perspective of CICS control programs and control tables.)?
TCP places data in TIOA and corresponding entry into TCT.
KCP acquires the transaction identifier from TIOA and verifies if it is present in PCT.
SCP acquires Storage in Task Control Area (TCA), in which KCP prepares control data for the task.
KCP then loads the application programs mentioned in PCT by looking for it in PPT.
If resident – real storage memory location is not present in the PPT the control is passed to PCP that loads the application program from the physical storage location address given in PPT. The control is then passed to the application program (LOAD module).
20. Specify the requirements for Automatic Task Initiation. (Mention the control table, it is entries and the corresponding Procedure division CICS command).?
DFHDCT TYPE = INTRA,
DESTIN = MSGS,
TRANSID = MSW1,
TRIGLEV = 1000
EXEC CICS WRITEQ TD
QUEUE(‘MSGS’),
FROM(DATA-AREA),
LENGTH(MSG_LEN)
END-EXEC.
21. What is the EIB parameter and the CICS command used to implement Pseudo-Conversational technique using single PCT – Single PPT entry?
EIBCALEN – To check if COMMAREA has been passed in terurn command.
EXEC CICS RETURN
TRANSID(data-name)
COMMAREA(data-area)
LENGTH (data-value)
END-EXEC
22. What are the two ways of breaking a CPU bound process to allow other task to gain access to CPU?
EXEC CICS DELAY EXEC CICS DELAY
INTERVAL(hhmmss) TIME(hhmmss)
END-EXEC END-EXEC
23. Mention the option (along with argument type) used in a CICS command to retrieve the response code after execution of the command?
RESP( S9(8) COM. )
24. Into what fields will the date and time values be moved after execution of the above command?
EIBDATE and EIBTIME.
25. What are the six different type of argument values in COBOL that can be placed in various options of a CICS command?
. Data Value – EX (Literal 8 or 77 KEYLEN PIC S9(4) COMP VALUE8.)
. Data Area – EX (01 RECORD-AREA. 05 FIELD PIC X(5).)
. Pointer-REF -EX (05 POINTER-I PIC S9(8( COMP.) . Name -EX (05 FIELD-NAME PIC X(5) VALUE ‘FILEA’.)
. Label – Cobol paragraph name
. HHMMSS – EX (77 TIMEVAL PIC S9(7) COMP3. )
26. What is the purpose of the Program List Table?
The Program List Table records the set of application programs that will be executed automatically at CICS start-up time
27. What is the function of the CICS translator?
The CICS translator convert the EXEC CICS commands into call statements for a specific programming language. There are CICS translator for Assembler, COBOL, and PL/1.
28. What does Pseudo Conversational mean?
The programming technique in which the task will not wait for the end-user replies on the terminal. Terminating the task every time the application needs a response from the user and specifying the next transaction to be started when the end user press any attention key ( (Enter, PF1 trough PF24, PF24, PA1, PA2 and clear) is pseudo-conversational processing.
29. Code the related portions of CICS/COBOL-I programs to gain addressability to TWA area assigned to a particular task. Assme that the size of TWA area is 300 bytes. What are the advantages if COBOL-II is used in the place of COBOL?
Code the above requirement in COBOL-II.
AN: LINKAGE SECTION.
01 PARMLIST.
02 FILLER PIC S9(8) COMP.
02 TWA-PTR S(98) COMP.
01 TWA-DATA-LAYOUT.
02 DATA-AREA PIC x(300)
PROCEDURE DIVISION.
……
EXEC CICS ADDRESS
TWA(TWA-PTR)
END-EXEC
SERVISE RELOAD TWA-DATA-LAYOUT.
COBOL-II PROGRAM
LINKAGE SECTION
01 TWA-DATA-LAYOUT.
05 DATA-AREA PIC X(300).
PROCEDURE ADDRESS
……
EXEC CICS ADDRESS
TWA(ADDRESS OF TWA-DATA-LAYOUT)
END EXEC
….
30. How and where is the TWA size set?
TWASIZE=300 in PCT table.
31. What is the most common way of building queue-id of a TSQ?
(Name the constituents of the Queue ID).
TERMID+TRANSACTION-ID.
32. What option is specified in the SEND command to send only the unnamed fields on to the screen?
MAPONLY
33. What is the COMMAREA (communications area)?
This is the area of main storage designed to let programs or task communicate with one another. used in programs via RETURN, XCTL and LINK commands.
34. How many conditions can you include in a single HANDLE CONDITION command?
No more than 16 in a single handle condition. If you need more, then you must code another HANDLE CONDITION command.
35. Explain how to handle exceptional conditions in CICS?
An abnormal situation during execution of a CICS command is called an exceptional condition:
1. Handle Condition Command: It is used to transfer control to the procedure label specified if the exceptional condition specified occurs.
2. Ignore Condition Command: It causes no action to be taken if the condition specified occurs in the program. That is control will be returned to the next instruction following the command which encountered the exceptional condition.
3. No Handle Option: This option can be specified in any CICS command and it will cause no action to be taken for any exceptional condition occurring during execution of this command.
4. RESP Option: This option can be specified in any CICS command. If the RESP option is specified in a command, CICS places a response code at a completion of the command. The application program can check this code, then proceed to the next processing.
36. What information can be obtained from the EIBRCODE?
The EIBRCODE tells the application program if the last CICS command was executed successfully and, if not, why not.
37. What is EIB, How is can be used?
CICS automatically provides some system-related information to each task in a form of EXEC interface BLOCK (EIB), which is unique to the CICS command level. We can use all the fields of EIB in our application programs right away.
38. What CICS command do you need to obtain the user logon-id?
You must code EXEC CICS ASSIGN with the OPENID option.
39. What are the differences between and EXEC CICS XCTL and an EXEC CICS LINK command?
The XCTL command transfer control to an application program at the same logical level ( do not expect to control back), while the lINK command passes control to an application program at the next logical level and expects controal back.
40. How is addressability achieved to the data outside programs working storage?
The Base Locator for Linkage (BLL) is an addressing convention used to address storage outside the Working Storage Section of an application program. If BLL is used for the input commands (e.g.: READ, RECEIVE), it will improve the performance, since the program would be accessing directly the input buffer outside of the program. In order to work as intended, the program must
Construct BLL based on the following convention:
1. The parameter list must be defined by means of a 01 level data definition in the Linkage Section as the first area definition to the Linkage Section, unless a communication area is being passed to the program, in which case DFHCOMMAREA must be defined first. The parameter list consists of a group of the address pointers, each of which is defined as the full word binary field ( S9(8) COMP). This is called the BLL cells.
2. The parameter list is following by a group of 01 level data definitions, which would be the actual data areas. The first address pointer of the parameter list is set up by CICS for addressing the parameter list itself. From the second address pointer onward, there is a one-to-one correspondence between the address pointer of the parameter list and 01 level data definitions.
3. VS COBOL II provides CICS application programs with a significant improvements in the area of addressability through the specifial ADDRESS register. Therefore, if an application program is written in VS COBOL II, the program is no longer requires building the B
41. Explain re-entrancy as applies to CICS?
Reentrant program is a program which does not modify itself so that it can reenter to itself and continue processing after an interruption by the operating system which, during the interruption, executes other OS task including OS tasks of the same program. It is also called a “reenterable” program or “serially reusable” program
A quasi-reentrant program is a reentrant program under the CICS enviroment. That is, the quasi-reentrant program is a CICS program which does not modify itself. That way it can reenter to itself and continue processing after an interruption by CICS which, during the interruption executes other tasks inluding CICS tasks of the same program. In order to maintain the quasi- reentrancy, a CICS application program must follow the follow convention:
Constants in Working Storage: The quasi-reentrant program defines only constants in its ordinary data area (e.g. working Storage Section). These constants will never be modified and shared by the tasks
Variable in Dynamic Working Storage: The quasi reentrant program acquires a unique storage area ( called Dynamic Working Storage – DWS) dynamically for each task by issuing the CICS macro equivalent GETMAIN. All variables will be placed in this DWS for each task. All counter would have to be initialized after the DWS has been acquired.
42. What happens when a CICS command contains the NOHANDLE option?
No action is going to be taken for any exceptional conditional occurring during the execution of this command. the abnormal condition that occurred will be ignored even if an EXEC CICS HANDLE condition exist. It has the same effect as the EXEC CICS IGNORE condition except that it will not cancel the previous HANDLE CONDTION for any other command.
43. What is the EXEC CICS HANDLE ABEND?
It allows the establishing of an exit so cleanup processing can be done in the event of abnormal task termination.
44. Explain the various ways data can be passed between CICS programs?
Data can be passed between CICS programs in three ways- COMMAREA, TRANSIENT DATA QUEUE $ TEMPORARY STORAGE QUEUE.
Data can be passed to a called program using the COMMAREA option of the LINK or XCTL command in a calling program. The called program may alter the data content of COMMAREA and the changes will be available to the calling program after the RETURN command is issued in the called program. This implies that the called program does not have to specify the COMMAREA option in the RETURN command.
If the COMMAREA is used in the calling program, the area must be defined in the Working Storage Section of the program (calling), whereas, in the called program, the area must be defined as the first area in the Linkage Section . using reserved name DFHCOMMAREA.
45. What are the CICS commands available for program control?
The following commands are available for the Program Control services:
1. LINK: To pass control to another program at the lower level, expectiong to be returned.
2. XCTL: To pass control to another program at the same level, not expecting to be returned.
3. RETURN: To return to the next higher-level program or CICS.
4. LOAD: to load a program
5. RELEASE: To release a program.
46. When a task suspends all the handle conditions via the PUSH command, how does the task reactivate all the handle conditions?
By coding an EXEC CICS POP HANDLE command
47. What is the difference between EXEC CICS HANDLE CONDTION and an EXEC CICS IGNORE command?
HANDLE CONDTION command creates a “go-to” environment. An IGNORE command does not create a go-to environment: instead. it gives control back to the next sequential instruction following the command causing the condition. They are opposites.
48. What is the function of the EXEC CICS HANDLE CONDITION command?
To specify the paragrph or program label to which control is to be passed if the “handle conditin” occurs.
49. What is the effect of including the TRANSID in the EXEC CICS RETURN command?
The next time the end user presses an attention key, CICS will start the transaction specified in the TRANSID option.
50. What is some of the information available in the EIB area?
I. The cursor position in the map
II. Transaction ID
III. Terminal ID
IV. Task Number
V. Length of communication area
VI. Current date and time
VII. Attention identifier
51. What is a resident program?
A program pr map loaded into the CICS nucleus so that is kept permanently in main storage and not deleted when CICS goes ” Short on Storage.”
52. What happens to resources supplied to a transaction when an XCTL command is executed?
With an XCTL, the working storage and the procedure division of the program issuing the XCTL are released. The I/O areas, the GETMAIN areas, and the chained Linkage Section areas (Commarea from a higher level) remain. All existing locks and queues also remain in effect. With a LINK, however, program storage is also saved, since the transaction expects to return and use it again.
53. What are the differences between and EXEC CICS XCTL and EXEC CICS START command?
The XCTL command transfer control to another application (having the same Transaction ID), while the START command initiates a new transaction ID (therefore a new task number). The XCTL continues task on the same terminal. START can initiate a task on another terminal.
54. How can you start a CICS transaction other than by keying the Transaction ID at the terminal?
By coding an EXEC CICS START in the application program
1. By coding the trans id and a trigger level on the DCT table
2. By coding the trans id in the EXEC CICS RETURN command
3. By associating an attention key with the Program Control Table
4. By embedding the TRANSID in the first four positions of a screen to the terminal.
5. By using the Program List Table.
55. Explain the means of supporting pseudo conversation programming. (Eg. Storing and restoring of states, control flow, error handling)?
When we send a map using SEND MAP command, Immediately we release the program by using EXEC CICS RETURN command. In this command we mention the TRANSACTION ID which is to be executed after receiving the map. In this command we also specify the data that should be stored in COMMUNICATION AREA for later use.
When this command is executed the corresponding program is released from the memory. After receiving the response from the terminal the program is again loaded and this time the data which we stored in communication area will be copied into the working storage section. And the map will be received with RECEIVE MAP command. The variable EIBCALEN in EIB holds the length of communication area.
In procedure division we checks the value of EIBCALEN if it is zero, we first send the map followed by RETURN command. Otherwise, that is if EIBCALEN is not zero, we know that this transaction is not running first time and we receive the map by using RECEIVE MAP command.
56. Which transient data queue support ATI?
INTRA-PARTITION Data queue.
57. Into which table is the terminal id registered?
TCT.
58. Which CICS service transaction is used to gain accessibility to CICS control tables? Mention the one that has the highest priority.?
CEDA
59. What is the function of the Terminal Control table?
To register all CICS terminals
60. What does the following transactions do?
CEDF:CICS-supplied Execution Diagnostic Facility transaction. It provides interactive program execution and debugging functions of a CICS programs.
CEMT: CICS-supplied Extended Master Terminal transaction. It displays or manipulates CICS control environment interactively.
CEBR: CICS-supplied Temporary Storage Browse transaction. It displays the content of Temporary Storage Queue (TSQ).
CECI: CICS-supplied Command Interpreter transaction. It verifies the syntax of a CICS command and executes the command.
61. What are the differences between Temporary Storage Queue (TSQ) and Transient Data Quene (TDQ)?
Temporary Storage Queue names are dynamically defined in the application program, while TDQs must first be defined in the DCT (Destination Control Table). When a TDQ contains certain amount of records (Trigger level), A CICS transaction can be started automatically.
This does not happen when using a TSQ. TDQ (extra partition) may be used by batch application; TSQ cannot be accessed in batch.
he Transient Data Queue is actually a QSAM file. You may update an existing item in a TSQ. A record in a TDQ cannot be updated. Records in TSQ can be read randomly. The TDQ can be read only sequentially. Records inTemporary Storage can be read more than once, while recordes stored in Temporary Data Queues cannot. With TDQs it is “one read” only.
62. Why is a TERM ID recommended in naming a TSQ?
In order to avoid confusion and to maintain data security, a strict naming convention for QID will be required in the installation. Moreover, for a terminal-dependent task (e.g. pseudo-conversation task), the terminal id should be included in QID in order to ensure the uniqueness of TSQ to the task.
63. What is a mapset?
A mapset is a collection of BMS maps link-edited together.
64. What are the three ways available for a program to position the cursor on the screen?
I. Static positioning. Code the insert cursor (IC) in the DFHMDF BMS macro.
II. Relative positioning. Code the CURSOR option with a value relative to zero (position 1.1 is zero)
III. Symbolic positioning. Move high values or -1 the field length in the symbolic map (and code CURSOR on SEND command ).
65. How to establish dynamic cursor position on a map? How to get the cursor position when we receive a map?
We dynamically position a cursor through an application program using a symbolic name of the symbolic map by placing -1 into the field length (i.e., fieldname + L) of the field where you wish to place the cursor. The SEND MAP command to be issued must have the CURSOR option (without value).
Also, the mapset must be coded with MODE = INOUT in the DFHMSD macro. We get the cursor position when we receive a map by checking EIBCPOSN, which is a halfword ( S9(4) COMP) binary field in EIB, and contains offset position (relatively to zero) of the cursor on the screen.
66. Can we define an alternate index on VSAM/RRDS?
No
67. Name three ways the Modified Data Tag can be set on?
The Modified Data Tag can be set on:
1. When the user enters data into the field.
2. When the application program moves DFHBMFSE to the attribute character.
3. By defining it in the BMS macro definition.
68. What is MDT?
MDT ( Modified Data Tag ) is one bit of the attribute character, If it is off (0), it indicates that this field has not been modified by the terminal operator. If it is on (1), It indicates that field has been modified by the operator. Only when MDT is on, will the data of the field be sent by the terminal hardware to the host computer (i.e. to the applcation progam in end).
An effective use of MDT drastically reduces the amount of data traffic in the communication line, thereby improving performance significantly. Therefore, BMS maps and CICS application program should be devloped based on careful considerations for MDT.
69. What is the difference between using the READ command with INTO option and SET option?
When we use INTO option with the READ command the data content of the record will be moved into the specified field defined in the Working Storage Section of the program. When we use SET option with the READ command, CICS sets the address pointer to the address of the record in the file input / output area within CICS,so that the application program can directly refer to the record without moving the record content into the Working Storage area defined in the program.
Therefore, the SET option provides a better performance than the INTO option.
70. What is the difference between the INTO and the SET option in the EXEC CICS RECEIVE MAP command?
The INTO option moves the information in the TIOA into the reserved specified area, while the SET option simple returns the address of the TIOA to the specified BLL cell or “address-of” a linkage-section.
71. What does it mean when EIBCALEN is equal to zeros?
When the length of the communication area (EIBCALEN) is equal to zeros, it means that no data was passed to the application.
72. Explain floating maps with illustration?
Maps which can positioon themselves relative to the previous maps on the screen or page are known as the floating maps. For this you have to use special positional operands to LINE and COLUMN parameters of the BMS macro definition. They are SAME, NEXT. Actually this floating map concept is there only in Full BMS where as it is not available in Min. or Standard BMS macros. RECEIVE MAP is not recommended in the case of floating maps. Hence these maps are normally used to send information such as selected records from a database to screen but not for data entry. A mapset can contain more than one map in it, you may use all these maps to build a screen.
In that case there are two ways to send these maps on to the screen.
i) Use separate SEND MAP commands one for each map involved. or
ii) Use ACCUM operand along with SEND MAP command and while sending really on to the screen use SEND PAGE to display them at one shot. The second one is called cumulative mapping scheme where you also can use foating maps.
Let’s take a situation where you have to build a screen like this
HEADER MAP (no. of A gr. employs)
DETAIL MAP ( employee list)
TRAILER MAP
73. What is the differences between getting the system time with EIBTIME and ASKTIME command?
The ASKTIME command is used to request the current date and time. Whereas, the EIBTIME field have the value at the task initiation time.
74. Explain the basic difference between Intra partition TDQ and Extra partition TDQ?
INTRA PARTITION TD QUEUEs. It is a goup of sequential records which are produced by the same and / or different transaction within a CICS region. These Qs are stored in only one physical file (VSAM) in a CICS region, which is prepared by the system programmer.
Once a record is read from a queuue, the record will be logically removed from the queue; that is the record cannot be read again EXTRA PARTITION TD QUEUEs It is a group of sequential record which interface between the transaction s of the CICS region and the systems outside of CICS region. Each of there TDQs is a separate physical file, and it may be on the disk, tap, printer or plotter.
75. What is the function of DFHMDF BMS macro?
The DFHMDF macro defines fields, literal, and characteristics of a field.
76. Which CICS system program is responsible for handling automatic task initialization?
The Transient Data Program (TDP).
77. How can the fact that EIBCALEN is equal to zeros be of use to an application programmer?
When working in a pseudo-conversational mode, EIBCALEN can be checked if it is equal to zero. A programmer can use this condition as a way of determining first time usage (of the program).
78. How can you prevent more than one user from accessing the same Transient Data Queue?
By issuing an EXEC CICS ENQ against the resource. When processing is completed, a DEQ should be executed.
79. Explain the term Transaction routing?
Transaction routing is a CICS mode of intercommunication which allows a terminal connected to local CICS to execute another transaction owned by a remote CICS.
80. What is ENQ in CICS?
If any one want to restrict Trans-ID to single user, enter trans-id with ENQ. It won’t allow any one else to use the same trans-id.
81. What is a deadlock?
Deadlock (also known as a “deadly embrace”) occurs when a task is waiting for a resource held by another task which, in turn, is waiting for a resources held by the first task.
82. In which CICS table would you specify the length of the TASK WORK AREA (TWA)?
In the Program Control Table (PCT).
83. Which CICS command must be issued by the application program in order to gain access to the Common Work Area (CWA)?
EXEC CICS ADDRESS with CWA option.
84. What information do you get when an EXEC CICS STARTCODE is issued?
You will be able to determine if the application was started by
(1) a transient data trigger level (QD),
(2) a START command (S,SD),
(3) user (U) or terminal input (TD), or
(4) Distributed Program Link (D, DS).
85. How do you define Task Work Area?
By defining it on the PCT ( the Program Control Table)
86. The DFHCOMMARA is used to pass information from one application to another. What are some other ways that this function can be accomplished?
You can also pass information in the following ways.
-By using a temporary storage queue.
-By using an intrapartion TDQ
-By using the Task Work Area
-By using TCTUA
-Through a file
87. When an apllication is invoked via the EXEC CICS START command with the from option, how does the application gain access to the common area?
An EXEC CICS RETRIEVE command will access the common area.
88. In an on-line environment, how can you prevent more than one user from accessing the same Transient Data Queue at the same time?
By issuing an EXEC CICS ENQ against the resource. When processing is completed, a DEQ should be executed.
89. Explain the term Function Request Shipping?
Function request shipping is one of the CICS modes of intercommunication which allows an application program in a local CICS to access resources owned by a remote CICS.
90. Explain the term MRO (Multi Region Operation)?
MRO is the mechanism by which different CICS address spaces with in the same CPU can comunication and share resources.
91. What are different system tables used in CICS?
PCT, FCT, TCT, DCT, PPT
92. What is multitasking and multithreading?
multitasking is the feature supported by the operating system to execute more than one task simultaneously. Multithreading is the system environment where the tasks are sharing the same programs load module under the multitasking environment. It is a subset of multitasking since it concerns task which use the same program.
93. What is the difference between link Xctl?
Link is temporary transfer of control. Xctl is permanent transfer of control
94. Name some of the common tables in CICS and their usage?
PCT Program Control Table – defines each transaction containing a list of valid transaction identifiers (transid) where each transaction is paired with its matching program;
PPT Program Processing Table – contains a list of valid program names and maps and whether a current version is in the CICS region or needs to be brought in as a new copy;
FCT File Control Table – contains a list of files known to CICS, the dataset name and status (closed/open, enable/disabled;)
TCT Terminal Control Table – a list of the terminals known to CICS.
95. Name some common CICS service programs and explain their usage?
Terminal Control, File Control, Task Control, Storage Control, etc, Each CICS service program controls the usage and status for its resource (file, terminal, etc) within the CICS region.
96. What is meant by a CICS task?
A CICS task exist from the time the operator presses the enter key until the application program returns control to CICS.
97. What is meant by program reentrance?
A program is considered reentrant if more than one task can execute the code without interfering with the other tasks’ execution.
98. What is the common systems area (CSA)?
The common systems area is the major CICS control block that contains system information, including pointers to most other CICS control blocks. The CSA points to all members of STATIC storage.
99. What is the EIB (execute interface block)?
The execute interface block lets the program communicate with the execute interface program, which processes CICS commands. It contains terminal id, time of day and response codes.
100. What is an MDT (Modified Data Tag)? Its menaing and use?
The modified data tag is the last bit in the attribute byte for each screen field. It indicates whether the corresponding field has been changed.