Memory refers to the physical devices used to store programs or data on a temporary or permanent basis for use in a computer or other digital electronic device.
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2answers
82 views
Loading database in memory vs querying
I am currently developing a continuous backup software. The key feature of the software is instant backup meaning that each time a file is created, modified, renamed or deleted the change is ...
-4
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0answers
43 views
Allocating memory inside a function and returning it back [migrated]
I want to pass a pointer to my function and allocate the memory to which this pointer points. I've read in other posts that I should pass a double pointer to this function and I did so, but I keep ...
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2answers
128 views
Estimation of space is required to store 275305224 of 5x5 MagicSquares? [closed]
Here are some examples of 5x5 Magic Squares found by the Magic Square Generator by Marcel Roos:
Magic squares 5x5
Sum must be: 65
Solution: 1
1 2 13 24 25
3 23 17 6 16
20 21 11 8 ...
12
votes
3answers
496 views
Debugging memory corruption
First off, I do realize this is not a perfect q&a style question with an absolute answer, but I can't think of any wording to make it work better. I don't think there is an absolute solution to ...
0
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0answers
61 views
Memory management scheme for custom memory allocator
I am in the process of implementing a small memory manager. The users of this memory pool will always access the memory bytes via handles. So a memory allocation/deallocation is done with two APIs:
...
3
votes
1answer
364 views
Why do programmers still use “SAFE_DELETE”? [closed]
If I had a dime for every time I've seen this macro in use, today I would be coding just for fun:
#define SAFE_DELETE(p) if ((p) != NULL) { delete (p); (p) = NULL; }
Why do programmers insist in ...
1
vote
1answer
81 views
In general: guard pages or heap checks? [closed]
I would like to know the advantages and disadvantages of using guard pages with bump-pointer allocation versus heap checks with bump-pointer allocation, including performance as a consideration.
In a ...
0
votes
2answers
144 views
Failed to allocate memory - What is it trying to say?
In my early days of programming I often used to get memory related fatal errors in the following format:
Fatal error: Allowed memory size of <some big number> bytes exhausted
(tried to ...
2
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4answers
357 views
In C++ Good reasons for NOT using symmetrical memory management (i.e. new and delete)
I try to learn C++ and programming in general. Currently I am studying
open source with help of UML. Learning is my hobby and great one too.
My understanding of memory allocation in C++ is that it ...
1
vote
1answer
195 views
Are there theoretical reasons why arrays in C take less RAM than Java?
My experience is that Java requires about twice as much RAM compared to C (comparing char arrays or other comparisons). I also read in a hardware book that Java takes about twice RAM than C. Is is ...
0
votes
3answers
159 views
How are negative signed values stored? [duplicate]
I was watching this video on the maximum and minimum values of signed integers.
Take an example of a positive signed value - 0000 0001
The first bit denotes that the number is positive and the last ...
4
votes
1answer
277 views
Writing a spell checker similar to “did you mean”
I'm hoping to write a spellchecker for search queries in a web application - not unlike Google's "Did you mean?" The algorithm will be loosely based on this: http://catalog.ldc.upenn.edu/LDC2006T13
...
0
votes
3answers
271 views
Why std::allocators are not that popular? [closed]
With the latest trends about C and C++ applications, and with latest I mean the latest years, I was expecting to see std::allocators to be used way more frequently than what it really is.
Modern ...
7
votes
3answers
353 views
Object Identity and Mutability
I was reading a proposal for value types in Java, and I came across this sentence: "Object identity serves only to support mutability, where an object’s state can be mutated but remains the same ...
1
vote
1answer
136 views
How to implement an algorithm out-of-core?
I want to implement a parallel clustering algorithm "out-of-core" in CUDA. My CPU has 12GB of RAM and GPU has 4GB of it.
What I want is that the entire dataset should be on the disk, and I can pick ...
5
votes
1answer
161 views
At ping, why do we have to do array copying instead of passing on the source array that the client sent to us?
So I have been googling about this OpenSSL heart-bleed thing and somehow sees that it is caused by the heartbeat extension which requires client to ping the server to show its aliveness and it all ...
3
votes
2answers
184 views
How to manage memory in C interface for C++ implementation considering c++11?
I have a library implemented in C++ which has a C interface. This C interface is, for all intents and purposes, the only way to use this library. C++11 seems to discourage the use of raw pointers but ...
0
votes
1answer
95 views
Worried about memory leak in DLL that creates a dynamic sized array
I have a wrapper DLL that interfaces to another DLL that contains the following function:
char * Foobar(void)
{
// BLAH is the function from the DLL this wrapper interfaces too
char *array ...
5
votes
2answers
207 views
Evaluation order of expressions in Clojure?
I'm currently learning Clojure (my first functional programming language), and I'm curious as to its order of evaluation.
Here is an example:
(take 10 (cycle [1 2 3]))
If the cycle expression was ...
0
votes
0answers
59 views
streaming data in memory aggregation
We have a stream of data we're aggregating stats over and putting into a python dictionary (sent from kafka). Every X time interval, We update our database with these aggregated metrics. This ...
0
votes
2answers
75 views
Multi-level paging tables
Referring to the image here:
From http://en.wikipedia.org/wiki/File:X86_Paging_4K.svg
Could somebody please explain something for me? I don't get exactly how this works. As I understand it the ...
38
votes
5answers
6k views
Why is CPU cache memory so fast?
What makes CPU cache memory so much faster than main memory? I can see some benefit in a tiered cache system. It makes sense that a smaller cache is faster to search. But there must be more to it.
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votes
1answer
114 views
How do memory-clean apps work? [closed]
In terms of operating system architecture, what does a memory-clean software to get rid of all data that fill the virtual memory? I assume that it simply saves all RAM data into a file, but how does ...
0
votes
3answers
155 views
Advantage of monitoring file change using Windows API rather than manually
I developed a Windows software about an year ago. Part of it was to monitor few configuration files for manual changes by user and if any of these change restart a particular service.
So, I used the ...
1
vote
1answer
919 views
how much memory should android app use [closed]
We are planning to develop an android application. the application will use API and data transfer will be via SSL.
I should write documentation and set functional and system requirements for the ...
4
votes
1answer
263 views
What are the benefits of Android way of “saving memory” - explicitly passing Context objects everywhere?
Turned out, this question is not easy to formulate for me, but let's try.
In Android, pretty much any UI object depends on a Context, and has defined lifetime. Android can also destroy and recreate UI ...
5
votes
2answers
326 views
Are there alternatives to stack+heap+static memory model?
All programs I have seen organize their data memory into one or more call stacks (usually fixed size, but sometimes not), the heap, and static memory. Lately thread-local static storage has been ...
7
votes
4answers
637 views
Why not free memory as soon as its reference counter hits zero [duplicate]
A lot of languages like Java and C# have garbage collectors that free memory when that memory no longer has any reference. Yet they don't immediately free it after the reference counter hits zero but ...
2
votes
2answers
477 views
Help me think in C++
I mainly use dynamic languages. For many years I see statically typed hello world examples like
const int STACK_SIZE = 100;
And I will think "wow, I can't think like that". I understand memory ...
2
votes
1answer
291 views
How does the CPU know when it received RAM data and instructions?
Well, the title is pretty much self explanatory, but I'll expound it a bit, and say the origin of my question.
So, I've been wondering as to how the CPU knows when it received the RAM. I'm pretty ...
0
votes
1answer
109 views
Multiple Instantiate of 1 class affects memory?
I am currently struggling with memory handling. I have an if statement and each case instantiate a new object from a class. Does this affect the memory allocation in java?
switch()
{
case 1:
test t1 ...
2
votes
4answers
463 views
Why do we use to talk about addresses and memory of variable in C?
Why do we use to talk about addresses and memory of variable in C, where in other languages (like in Java, .Net etc) we do not talk about variable address and memory in a program, we will directly use ...
0
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2answers
1k views
Can anyone explain representation of float in memory?
This is not duplicate question as I read the previous question.
Can anyone help me in understanding how float values are stored in the memory .
My doubt is here float values contain '.' (for example ...
-1
votes
2answers
85 views
Applications affected by memory performance [closed]
I'm writing a paper on the topic of applications affected more by memory performance than processor performance. I've got a lot written regarding the gap between the two, however I can't seem to find ...
12
votes
1answer
617 views
How important it is to fix memory leaks?
I found by Valgring that some GTK+ programs leaks memory. How important it is to fix those leaks? I mean, often those programs works very well but on the other hand, one can never be sure if one wants ...
4
votes
3answers
421 views
Multiple sites with the same codebase in Python
I am trying to run a large amount of sites which share about 90% of their code. They are simply designed to query an API and return the results. They will have a common userbase / database but will be ...
1
vote
1answer
2k views
External sqlite db file from sdcard in android
I just searched for the same but didn't get the answers. What I have is a db file which is around 100MB. I have saved the db file in sdcard .
Through this db file I'm going to populate the contents ...
0
votes
1answer
170 views
Will having ClassA extend ClassB slow down my runtime performance compared to having classC which contains all the members of ClassC?
I have a class with a lot of methods. I would like to group similar methods together in their own class, but all of the methods need to extend another class, ClassC. So I was thinking of having ...
11
votes
3answers
4k views
What are CPU registers?
This question has been bothering me for some time now and today I figured I would Google it. I've read some stuff about it and it seemed very similar to what I've always known as processor cache.
Is ...
3
votes
2answers
379 views
Methods to identify and resolve memory leaks in the JVM
As the data is migrated via the object level, there has been a slow upwards trend in memory usage. I can see the periodic gc activity, but the memory trend is still going up slowly. I have currently ...
4
votes
1answer
387 views
Does having more classes necessarily increase the memory requirements of the app?
When we add .edmx files to a DLL, the physical size of the DLL increases. DLL's are loaded into memory. However, the .NET infrastructure with functionality such as JIT compilation and the GAC ...
10
votes
2answers
1k views
Haskell memory efficiency - which is the better approach?
We are implementing a matrix compression library based on a modified two dimensional grammar syntax. Now we have two approaches for our data types -which one will be better in case of memory usage? ...
6
votes
2answers
3k views
How are the size of the stack and heap limited by the OS?
Note: if you need to consider a specific OS to be able to answer, please consider Linux.
Whenever I run a program, it will be given a virtual memory space to run in, with an area for its stack and ...
2
votes
2answers
616 views
Flat addressing vs. segmented addressing
Is flat addressing model generally superior to a segmented one? If so, why? If not, what instances would call for each over the other and why?
My understanding of memory models surrounds the ...
3
votes
2answers
491 views
What is the best solution for static memory allocation?
I'm working on image processing and I need to use big Images in a critical system.
A good practice for critical systems is to avoid dynamic allocation of memory but what is the design/recommendations ...
1
vote
1answer
185 views
Improving the efficiency of containers with dynamically allocated objects
This is not strictly related to C++ but its type system serves to illustrate the problem well.
Assume:
We have a generic template Container<T> (such as a std::vector<T>) which stores an ...
6
votes
6answers
589 views
Demonstration of garbage collection being faster than manual memory management
I've read in many places (heck, I've even written so myself) that garbage collection could (theoretically) be faster than manual memory management.
However, showing is a lot harder to come by than ...
2
votes
1answer
114 views
Handling Dynamic amount of Strings for persistent and runtime storage in an IOS App
Background
I am dynamically building an FQL query statement and because of the nature of the app, I exclude FB family members, this is the base portion of the query and remains fairly static. The ...
2
votes
1answer
139 views
Is every object rounded to the same size in Java?
According to this answer every object in Java is of the same size? Is the answer talking about the object itself or the reference to the object?
Here's the statement:
every object size is rounded ...
8
votes
2answers
383 views
Is there a comparative study of the memory consumption of programming languages runtimes, correlated with expressiveness and production bug ratios? [closed]
There are many comparative studies and available online when it comes to the runtime performance of applications built using one language or another. Some driven by corporations, some academic, some ...
