Memory Management
interview questions on memory
1. What are the types of memory?
Ans:The basic types of memories that a computer has:
1. RAM(random access memory)
2.ROM(read Only memory)
3.Cache Memory
4.Other than these a computer also has secondary storage devices like a hard disk which also contribute towards it memory.
Q 2.Define Compaction.
Ans:Compaction is a process in which the free space is collected in large memory chunk to make some space available for process.
Q 3. What is Dirty bit?
Ans:When a bit is modified by the CPU and not written back to the storage,it is called as a dirty bit.
This bit is present in the memory cache or the virtual storage space.
Q 4.What is page fault & when does it occur?
Ans: A page is a fixed length memory block used as a transfering unit between physical memory and an external storage.A page fault occurs when a program access a page that has been mapped in address space , but has not been loaded in the physical memory.
Q 5. What is SGA?
Ans: SGA – Stands for System Global Area, its a part of Memory structure! SGA consists of Shared Pool Database Buffer Cache Redo Log Buffer Lock & Latch Management & More Aditional Memory Structures Large pool & Java Pool
another name of SGA is Shared Global Area. It is used to store database information that is shared by database processes. It contains Data and control information for the Oracle Server and is allocated in the Virtual Memory of the computer – where Oracle Resides.
Q6. What is a shared pool?
Ans: The Shared Pool environment contains both fixed and variable structures. The Fixed structures remain relatively the same size, whereas the variable structures grow and shrink based on user and program requirements.
Used To Store
Most Recently Executed SQL Statements
Most Recently used Data definitions
It Consists of two Key performance – related memory structures
Library Cache & Data Dictionary Cache
Shared Pool is sized by SHARED_POOL_SIZE
Q7. What are the three tricks used to resolve absolute addresses?
1.Position Independent Code [PIC]
2.Relocation
3.Base and Limit Registers
Q8. What is dictionary cache ?
Ans: Dictionary cache is information about the databse objects stored in a data dictionary table.
Q9. What is hit ratio ?
Ans: It is a measure of well the data cache buffer is handling requests for data. Hit Ratio = (Logical Reads – Physical Reads – Hits Misses)/ Logical Reads.
Q10. What is meant by redo log buffer ?
Ans: Changes made to entries are written to the on-line redo log files. So that they can be used in roll forward operations during database recoveries. Before writing them into the redo log files, they will first brought to redo log buffers in SGA and LGWR will write into files frequently. LOG_BUFFER parameter will decide the size.
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The function of the read-only memory is something you already gain from the teenage but still, the information which is posted in the above article for you all is very much useful and it will help.the management of the memory is very much important and it is obtained in the operating system too.
This post contains important information in the field of computer science.
The memory management subsystem is one of the most important parts of the operating system. Since the early days of computing, there has been a need for more memory than exists physically in a system. Strategies have been developed to overcome this limitation and the most successful of these is virtual memory.