Mainframe Interview Questions and Answers
Q1. Explain Paging Concept in memory.
Ans: Whenever a particular facts object is requested, the CPU hits number one reminiscence or RAM first to peer if the document similar to the information item is present in any web page in number one reminiscence. If not, it does paging and brings within the correspong web page from secondary/auxiliary reminiscence or hard disk to number one reminiscence and then returns the facts object to the person.
Q2. Explain why we can't define occurs clause at 01 level.
Ans: 01 is of the record stage. We repeat the fields inside a record now not the file itself. So occurs clause can't be used at 01 stage.
Q3. What is Defragmentation and What is its gain?
Ans: The procedure of combining the scattered allotted areas for a file in a unmarried or few contiguous areas in place of multiple regions is referred to as defragmentation. Defragmentation reduces the range the seeks to retrieve the statistics.
Q4. Explain IS NUMERIC Clause.
Ans: IS NUMERIC Clause is used to test if any item is numeric or not. It returns TRUE whilst the item towards which it's far used carries most effective numbers(0 to nine). The object may be +ve or -ve. IS NUMERIC may be used towards Numeric, Alpha Numeric, Packed Decimal fields whether or not signed or no longer.
Q5. What is downtime and what might be the cause?
Ans: Downtime is the very brief period that the device isn't to be had. It is typically accomplished for preservation sports for the mainframe. In the uncommon cases, it's miles because of gadget outage.
Q6. Explain inner Sort and External Sort.
Ans: Internal Sort:
SORT report-1 ON ASCENDING/DESCENDING KEY key[,key1,….] USING document-2 GIVING record-3.
USING may be substituted by way of INPUT PROCEDURE IS para-1 THRU para-2
GIVING may be substituted via OUTPUT PROCEDURE IS para-1 THRU para-2.
Record-1 is the sort (work) file and should be defined as SD entry in FILE SECTION.
Report-2 is the input document for the SORT and need to be described as FD entry in FILE SECTION
record-3 is the out record from the SORT and must be defined as FD access in FILE SECTION.
Record-1, record-2 & document-three must now not be opened explicitly.
INPUT PROCEDURE is performed before the type and facts need to be RELEASED to the type paintings record from the input manner.
OUTPUT PROCEDURE is performed after all data were sorted. Records from the kind work record need to be RETURNED one at a time to the output process.
External kind is the one that's coded in JCL. External type is greater green.
Q7. What is SLA?
Ans: SLA is Service Level Agreement between the consumer and the seller. It is great in support systems in which the terms will be like reaction should be given within hours that an abend has passed off or for on line structures, the system need to no longer be down for the duration of consumer daylight.
Q8. Explain distinction among CONTINUE and NEXT SENTENCE.
Ans: Continue transfers the control to next declaration after the scope terminator. Next sentence transfers the control to announcement after the primary period encountered.
Q9. What is a Configuration Management device, provide examples?
Ans: A configuration management gadget is typically utilized in improvement environments to keep versioning of the developmental code to avoid any overlay of code by means of extraordinary builders operating on the identical code. It enables hold the integrity and consistency of the code throughout environments.
CHANGEMAN and ENDEVOR are examples of configuration management in mainframe.
Q10. Can I redefine X(10) with X(20). What happens if I achieve this?
01 WS-1 PIC X(10).
01 WS-2 REDEFINES WS-1 PIC X(20).
MOVE ‘MY NAME IS MAINFRAME’ TO WS-2.
The above assertion displays ‘MY NAME IS’
The above announcement shows ‘MY NAME IS MAINFRAME’