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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The same objects are staying in memory across multiple executions

I was testing a neural net I created, and noticed something odd. The net uses a hashed adjacency list (roughly) to maintain its links. The vertices of the list are the nodes of the net. I chose to ...
12
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2answers
359 views

What uses does Smalltalk’s ‘become:’ have?

The become: message in Smalltalk causes one object to change into another, affecting all references to it. What uses does this language feature have? Does it get used in real code? Is it just a ...
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2answers
65 views

What is a latency-bound and a memory-bound application in HPC?

I understand that in HPC hybrid systems, for instance a MIC architecture, main memory access is much slower than access to data in own cache or in the cache of another core. I read that HPC MIC ...
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About BMP file. How can i write/change a pixel color? (in C) [migrated]

I'm trying to change a pixel from a picture (format bmp, 24 bits). I have this 3 structures: for file header: #pragma pack(2) typedef struct { unsigned short int typeID; unsigned int size; unsigned ...
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2answers
26 views

Memory page - virtual or physical and relation to data types allocation?

I'm looking for a understandable definition of memory pages. Please help me clarify the following questions: Is a "memory page" always related only to a data chunk of virtual memory? Are physical ...
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1answer
91 views

Android & OutOfMemoryError: Possible causes besides memory leak?

In my application I keep receiving crash reports where the root cause is an OutOfMemoryError. The app is quite image heavy (I use Picasso for all the image loading) and also has a WebView component ...
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0answers
50 views

Class to manage EEProm Memory for microcontroller in .netMF

I've got a working driver to access the EEPROM chip, but looking for much better management and access of the memory. I've been racking my brain about what's the best or correct approach to do this. ...
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2answers
228 views

Does sun.misc.Unsafe give access to the system or just the JVM?

Please note: Although this question involves microcontrollers, it is at its core, a Java question, and so I believe it can be answered by any battle-weary Java guru. I stumbled accross this blog ...
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2answers
88 views

Should I set values using the return or by giving a reference?

Suppose I have a mouse position watcher, which should let the user extract the mouse position. Should the mouse position be set in the method and returned: Mouse_Position ...
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1answer
55 views

Memory Limit of a Single Program and mmap

If one has a 32 bit machine, a single program cannot address more than 2^32 bytes, or 4 GB. Would making use of mmap() allow one to exceed the 4 GB limit?
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1answer
192 views

Are there real world examples demonstrating reasonable performance improvement by using move semantics?

(I've asked a similar question on SO but unfortunately it might not be proper, so I also put here; please kindly point out if you think it's a duplicate.) I've heard many words about the move ...
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5answers
900 views

How to share memory between applications written in C/C++

I'm going through a program written in C/C++ for control in robotics. Basically, three different programs run at the same time, and they communicate via shared memory. Google-ling around I found ...
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1answer
238 views

How can C++ make it possible to use dynamic container classes even in embedded systems?

How can C++ make it possible to use dynamic container classes even in embedded systems? Background info: I've been working with PIC (C) and AVR (C++) processors and at the moment (PIC C) I'm ...
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1answer
65 views

Translation Lookaside buffer - Lookup By Page Size

I am having a hard time finding documentation that explains precisely how the various TLB caches are used in modern processors. Most modern processors have separate TLBs for code/data. That in itself ...
109
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9answers
9k views

When is it a good idea to force garbage collection?

So I was reading a question about forcing the C# garbage collector to run where almost every single answer is the same: you can do it, but you shouldn't - except for some very rare cases. Sadly, ...
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0answers
29 views

Cache Memory Vs Main Memory [duplicate]

Why is the access time of the cache memory lesser than the access time of the main memory? I have tried looking at the sites as - tutorialspoint.com, education-portal.com etc. I know that the ...
3
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2answers
205 views

Place variables frequently used by the same function on the heap?

Say that I have the following situation: void myFunc() { int x; //Do something with x } "x" is placed on the stack which is no doubt fast. Now, "myFunc" is called very frequently, lets say ...
3
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2answers
348 views

Best practice for uploading large file, previewing, and editing before saving to database?

I am allowing users to upload a relatively large .csv file (about 1MB) - it will contain thousands of records that each represent one of my business objects. I want the users to upload the file and ...
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1answer
98 views

Architecture question about data migration

I'm facing a new enterprise project in Java about data migration. I did one of them in the past, now I want to do a better work and I think I need your considerations. So, let's me explain the ...
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1answer
210 views

Relation between cache line and memory page

If I am correct, a page in a main memory is the smallest unit unit for transfer data between the main memory and an external storage device, such as a hard disk. A cache line of a main memory is the ...
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1answer
827 views

Facing MemoryError in Python

I wrote a program to find prime factors of a number. When I give a large number(600851475143) as input, MemoryError pops up. Below is the code: def fact(a): factors = [] for i in ...
2
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1answer
363 views

Understanding memory update propagation in x86/x86-64 CPU L1/L2/L3 caches and RAM

I'm trying to understand in a general sense how L1/L2 (and now L3 caches) are updated and how the updates are propagated in a multi-core x86/x86-64 CPU to the other cores and eventually RAM. Assuming ...
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5answers
248 views

Correctly disposing objects upon server termination

I am working on a large C++ project. It consists in a server that exposes a REST API, providing a simple and user-friendly interface for a very broad system comprising many other servers. The codebase ...
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1answer
525 views

Calculating physical address given only an offset for my process

Learning about virtual memory with an program assignment. Currently this is what I have: Main memory has 60 bytes and virtual memory another 60 bytes. The size of a frame/page is 10 bytes. So there ...
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3answers
163 views

Can a process that needs 15 MB run given a machine with 10 MB of physical memory and 10 of virtual?

So there is physical and virtual memory. Let's say we have 10 MB physical and 10 MB virtual. There is also paging. As far as I get it, paging basically splits physical and virtual memory into slots ...
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1answer
72 views

Is it possible to quickly change an array declared on the stack to one declared on the heap

I have about 5000 lines of code which manipulates a large array in C++. The problem is that when I try to make the array even larger i.e. A[10000][10000], the gcc compiler throws me a segmentation ...
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2answers
135 views

memory needed to store a function in javascript

I have been using sizeof.js to investigate the size of various objects in javascript. It appears from this that the size of a function is essentially zero bytes, regardless of how many instructions ...
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2answers
253 views

Autoreleasing objects in Reference Counting Systems

I'm experimenting a bit in C and I'm trying to implement my own Reference Counting System. I've mainly worked with Objective-C in the past but AFAIK autoreleasing objects is something that is unique ...
6
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1answer
231 views

Does assigning NULL in a GC'ed Environment have similar effects to using free()?

I was just writing a function (in C# in this case) that stored huge amounts of data in a local variable early on in the code, let's say at 5% of the functions code. After that point, the data in this ...
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2answers
201 views

How does the CPU access the values of stack-allocated variables? [duplicate]

Consider the following C++ function: void doStuff() { Thing thingA; Thing thingB; thingA.doSomething(); // .. etc } During the execution of this function, variables thingA and ...
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1answer
494 views

JVM memory and zero-copy (de)serialization

I am trying to understand the JVM memory model. In particular, I would like to understand whether it would be feasible to have zero-copy (de)serialization libraries, such as Cap'n Proto or ...
2
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2answers
2k views

When I create an object, is fresh memory allocated to both instance fields and methods or only to instance fields

I have a following class class Student{ int rollNumber; int marks; public void setResult(int rollNumber, int marks){ this.rollNumber=rollNumber; this.marks=marks; } public void ...
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1answer
141 views

What effect does using multiple childViewControllers views inside a ContainerViewController have on memory?

I have three childViewController views inside my ContainerViewController and these three views are inside a horizontal scroll view. My intention is to build an app that has a custom camera on one ...
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6answers
744 views

What are memory addresses? [closed]

I have more or less 0 knowledge in low-level topics, so forgive my possible ignorance. I know that in languages such as C, pointers hold 'memory addresses', i.e. strings (or binary data?) written in ...
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2answers
162 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 ...
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2answers
212 views

Estimation of space is required to store 275305224 of 5x5 MagicSquares? [closed]

Here are some examples of 5x5 Magic Squares found by some good solvers : Magic Square Generator by Marcel Roos this program state using 2.4GHz Intel takes about 95 hours to generate all solutions. ...
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4answers
1k 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 ...
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1answer
516 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 ...
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2answers
256 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 ...
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4answers
606 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 ...
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1answer
277 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
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3answers
3k 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
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1answer
466 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 ...
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3answers
641 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 ...
8
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3answers
428 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
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1answer
147 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
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1answer
166 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
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2answers
295 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 ...
1
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1answer
396 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 ...
4
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2answers
251 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 ...