Table of Contents
- 1 What is a memory error in C?
- 2 What causes memory leaks C?
- 3 What will happen if you malloc and free instead of delete?
- 4 What happens if you don’t deallocate memory?
- 5 Why is it important to deallocate memory?
- 6 How do I allocate more memory to heap?
- 7 Which memory allocation is best?
- 8 Which is the fastest memory management scheme?
- 9 What is compaction Why is it needed?
- 10 What is the memory compaction Mcq?
- 11 What is Trojan Horse Mcq?
- 12 What is a Trojan Horse 2 answer choices?
- 13 Is a Trojan horse a backdoor?
- 14 What is a backdoor virus?
- 15 Which type of hacker represents the highest risk?
- 16 What is the simplest way to stop brute force attacks dead in their tracks?
What is a memory error in C?
Memory errors are particularly easy to make in C and can be very hard to debug. Reactis for C automatically detects memory errors. A memory error occurs whenever a program reads-from or writes-to an invalid address.
What causes memory leaks C?
Memory leaks occur when new memory is allocated dynamically and never deallocated. In C programs, new memory is allocated by the malloc or calloc functions, and deallocated by the free function. One of the most common mistakes leading to memory leaks is applying the wrong delete operator.
How do you prevent memory leaks in C?
To avoid memory-related problems, it is good practice to:
- Always use memset along with malloc, or always use calloc .
- Whenever writing values to pointers, make sure you cross check the number of bytes available and number of bytes being written.
Why do you have to free memory in C?
In C, the library function malloc is used to allocate a block of memory on the heap. The program accesses this block of memory via a pointer that malloc returns. When the memory is no longer needed, the pointer is passed to free which deallocates the memory so that it can be used for other purposes.
What will happen if you malloc and free instead of delete?
If free() is not used in a program the memory allocated using malloc() will be de-allocated after completion of the execution of the program (included program execution time is relatively small and the program ends normally).
What happens if you don’t deallocate memory?
If you lose all pointers to a chunk of memory without deallocating that memory then you have a memory leak. Your program will continue to own that memory, but has no way of ever using it again.
When Deallocating a memory location pointed to by a pointer?
When you want to deallocate a memory location pointed to by a pointer, you first need to load the memory location that has been assigned by the pointer.
What is deallocation of memory?
Deallocation of memory by the Operating System (OS) is a way to free the Random Access Memory (RAM) of finished processes and allocate new ones. A process has to be loaded into the RAM for its execution and remains in the RAM until its completion.
Why is it important to deallocate memory?
It is always a good habit to free memory after it is no longer needed, even if the application is terminating. If you use a tool to detect memory leaks or similar problems, then deallocating memory will clean up the output of such tools.
How do I allocate more memory to heap?
In C, dynamic memory is allocated from the heap using some standard library functions. The two key dynamic memory functions are malloc() and free(). The malloc() function takes a single parameter, which is the size of the requested memory area in bytes. It returns a pointer to the allocated memory.
How will you check if a memory allocated at the heap is deleted or not?
While there are system specific approaches which will probably be able to tell whether memory is from heap or from a stack, that actually doesn’t really help: you may have got a pointer to a member of another object on the heap. The memory would be on the heap but you are still not responsible for deleting the object.
What are the various memory allocation techniques?
The two fundamental methods of memory allocation are static and dynamic memory allocation. Static memory allocation method assigns the memory to a process, before its execution. On the other hand, the dynamic memory allocation method assigns the memory to a process, during its execution.
Which memory allocation is best?
A partition allocation method is considered better if it avoids internal fragmentation. When it is time to load a process into the main memory and if there is more than one free block of memory of sufficient size then the OS decides which free block to allocate. 1.
Which is the fastest memory management scheme?
Shared memory is one of the fastest techniques for inter-process communication. Memory is usually classified by access rate into primary storage and secondary storage.
What is memory compaction?
Memory compaction is the process of moving allocated objects together and leaving empty space together. Consider a system with 3 pages and about 50% of their objects are allocated.
What does compaction mean?
Compaction refers to combining of all the empty spaces together and processes. Compaction helps to solve the problem of fragmentation, but it requires a lot of CPU time. It moves all the occupied areas of storage to one end and leaves one large free space for incoming jobs, instead of numerous small ones.
What is compaction Why is it needed?
Why is Soil Compaction Important? Soil compaction is necessary to increase the bearing capacity and stiffness of in-situ (natural state) or chemically modified soils. Compaction increases the shear strength of soils by adding friction from the interlocking of particles.
What is the memory compaction Mcq?
mcq on memory management. what do you mean by memory compaction? combine multiple equal memory holes into one big hole combine multiple small memory holes into one big hole divide big memory hole into small holes.
Which register is memory pointer?
The instruction pointer, IP, is also often referred to as the program counter. This register contains the memory address of the next instruction to be executed.
What type of fragmentation still exists?
There are three different but related forms of fragmentation: external fragmentation, internal fragmentation, and data fragmentation, which can be present in isolation or conjunction. Fragmentation is often accepted in return for improvements in speed or simplicity.
What is Trojan Horse Mcq?
This set of Cyber Security Multiple Choice Questions & Answers (MCQs) focuses on “Attack Vectors – Trojans and Backdoors – 1”. 1. Explanation: A Trojan is a small malicious program that runs hidden on the infected system. They are created with the intent and they infected the system by misleading the user.
What is a Trojan Horse 2 answer choices?
In computing, a Trojan horse is a program downloaded and installed on a computer that appears harmless, but is, in fact, malicious. When the user clicks on the email attachment or downloads the free program, the malware that is hidden inside is transferred to the user’s computing device.
What are zombie systems?
A Zombie is a malicious program that is installed on a device that transforms it into a “zombie” that attacks other systems. A computer or other device transformed by zombie malware is first infected by a virus or Trojan. It hijacked the computing power of laptops, then sufficient to mine digital currency. …
What is the difference between a backdoor and a Trojan?
A trojan is a type of malware that masquerades as a legitimate program to trick the recipient into running it. A backdoor is a specific type of trojan that aims to infect a system without the knowledge of the user.
Is a Trojan horse a backdoor?
Trojan definition A Trojan horse or Trojan is a type of malware that is often disguised as legitimate software. Once activated, Trojans can enable cyber-criminals to spy on you, steal your sensitive data, and gain backdoor access to your system.
What is a backdoor virus?
A backdoor is a malware type that negates normal authentication procedures to access a system. As a result, remote access is granted to resources within an application, such as databases and file servers, giving perpetrators the ability to remotely issue system commands and update malware.
Why would hackers want to cover their tracks Mcq?
Explanation: Hackers cover their tracks to keep from having their identity or location discovered.
How do hackers hide themselves?
Hackers will often use secure software such as a proxy server to hide their identity and funnel their communications through lots of different countries in order to evade detection. Other technologies like Tor and encryption enable them to add multiple layers to mask their identity.
Which type of hacker represents the highest risk?
5. Which type of hacker represents the highest risk to your network?
- Black-hat hackers.
- Grey-hat hackers.
- Script kiddies.
- Disgruntled employees.
What is the simplest way to stop brute force attacks dead in their tracks?
What is the simplest way to stop brute-force cyberattacks dead in their tracks? C. Add a few unique characters to any password or PIN.