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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7
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5answers
105 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 ...
0
votes
1answer
57 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 ...
1
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3answers
129 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 ...
1
vote
1answer
63 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 ...
14
votes
6answers
941 views

Term for 24-bits

Is there a term for a 24-bit (3-byte) integer? I know uncommon bit counts (such as a "nibble" or "nybble" for 4 bits) have names, and having 24-bits in both video and audio technology, for instance, ...
-1
votes
2answers
181 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. ...
27
votes
5answers
53k views

Stack and Heap memory in Java

As I understand, in Java, stack memory holds primitives and method invocations and heap memory is used to store objects. Suppose I have a class class A { int a ; String b; ...
0
votes
2answers
71 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 ...
7
votes
2answers
205 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
votes
1answer
195 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 ...
1
vote
2answers
132 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 ...
0
votes
1answer
109 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 ...
1
vote
2answers
189 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 ...
0
votes
1answer
70 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 ...
2
votes
6answers
441 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 ...
-1
votes
2answers
98 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 ...
12
votes
3answers
647 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 ...
4
votes
1answer
296 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 ...
3
votes
1answer
425 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
108 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 ...
4
votes
3answers
465 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 ...
0
votes
2answers
168 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
votes
4answers
415 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 ...
6
votes
6answers
713 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 ...
1
vote
1answer
219 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 ...
4
votes
1answer
325 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 ...
14
votes
5answers
13k views

Why does IIS default to Recycling the Application Pool every 1740 minutes?

Why does IIS default to recycle the app pool after a given time? Is there some specific reason other than perhaps most web apps are not managing the memory prudently? Given that you are managing your ...
0
votes
3answers
392 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 ...
8
votes
3answers
379 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 ...
0
votes
3answers
348 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 ...
1
vote
1answer
139 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
164 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
208 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
vote
1answer
179 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
votes
2answers
221 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
70 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
110 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
7k 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.
2
votes
4answers
473 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 ...
25
votes
1answer
625 views

Performance of single-assignment ADT oriented code on modern CPUs

Working in immutable data with single assignments has the obvious effect of requiring more memory, one would presume, because you're constantly creating new values (though compilers under the covers ...
10
votes
4answers
8k views

How can I monitor the JVM memory in a proper way?

I'm thinking of how we do JVM memory monitor in a low overhead way in production environment even under busy hour. Suppose I have two tomcat app server in production, load balance set up behind them. ...
-1
votes
1answer
127 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
207 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
2k 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 ...
6
votes
2answers
369 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 ...
35
votes
7answers
3k views

In C++, how much programmer time is spent doing memory management

People who are used to garbage collected languages are often scared of C++'s memory management. There are tools, like auto_ptr and shared_ptr which will handle many of the memory management tasks for ...
12
votes
11answers
1k views

Could it be more efficient for systems in general to do away with Stacks and just use Heap for memory management?

It seems to me that everything that can be done with a stack can be done with the heap, but not everything that can be done with the heap can be done with the stack. Is that correct? Then for ...
7
votes
4answers
673 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
484 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
356 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 ...