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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3
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1answer
310 views

Why do programmers still use “SAFE_DELETE”?

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
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1answer
78 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
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2answers
134 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
333 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
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1answer
183 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
124 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
261 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
242 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
349 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
134 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
160 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
157 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
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1answer
80 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
198 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
42 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
69 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 ...
39
votes
5answers
5k 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.
-1
votes
1answer
112 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
126 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
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1answer
650 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
209 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
313 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
620 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
473 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
280 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
108 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
458 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 ...
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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
602 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 ...
5
votes
3answers
401 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
165 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
3k 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
343 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
381 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? ...
5
votes
2answers
2k 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
569 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
442 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
181 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
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6answers
547 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
110 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
368 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 ...
20
votes
5answers
2k views

How did they debug segmentation faults before protected memory?

Now, when I make a programming mistake with pointers in C, I get a nice segmentation fault, my program crashes and the debugger can even tell me where it went wrong. How did they do that in the time ...
24
votes
1answer
594 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 ...
2
votes
4answers
281 views

Architecture change from using disk to RAM to read and write key/value pairs coming over a network

A WebApp writes a stream of data coming over a network to disk as key/value pair and then reads & send it over network again after few milliseconds in 99% of case. In 1% of cases write/read can be ...
3
votes
2answers
748 views

How many `malloc` calls is too many? If any?

I'm implementing a system in C, implemented partially as a library. The library does most of the memory management itself, with the application layer just having to call *_destroy functions on the ...
2
votes
4answers
248 views

Should I read a chapter about Memory management if now a days we mostly use ARC?

I'm reading a book on Objective C, and I was wondering about 2 things: Should I take the time currently to read a whole chapter on memory management? If you are doing a really good job on manual ...