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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8
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1answer
203 views

Why are C string literals read-only?

What advantage(s) of string literals being read-only justify(-ies/-ied) the: Yet another way to shoot yourself in the foot char *foo = "bar"; foo[0] = 'd'; /* SEGFAULT */ Inability to elegantly ...
-5
votes
2answers
76 views

Does CPU need local cache if Intel and Micron 3D XPoint is used? [on hold]

As Intel and Micron stated, the new 3D XPoint RRAM is 1,000 times faster than NAND. See link here. From speed perspective, does CPU still need L1 cache if Intel & Micron 3D XPoint RRAM is used as ...
0
votes
0answers
3 views

Beginner in C needing help with strings and memory [migrated]

So this course I'm doing wants us to play around with memory management and pointers. I'm not really fully understanding them. I keep getting a "Segmentation fault (Core dumped)" error. Apparently I ...
1
vote
3answers
122 views

Pre-calculate values or not on Raspberry Pi

Say that you want to rotate something 360 steps 100 times. You now have a choise to pre-calculate 360 sin and cos values once and then use the stored values 100 times, or you can calculate sin and cos ...
0
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0answers
26 views

Can MCU ROM and RAM limitations be scaled? [migrated]

Please note: Although this specific question has to do with the 32-bit ARM SAM3X8E Cortex M3 series, it is really a generic question that should be applicable to all microcontrollers, and therefore ...
0
votes
2answers
720 views

How are new[] and malloc implemented in Windows? [closed]

So when you call malloc or new [] from your C/C++ application, how does the CRT translate it into Windows API calls?
1
vote
0answers
76 views

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
votes
1answer
379 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 ...
1
vote
2answers
66 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 ...
0
votes
2answers
27 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 ...
1
vote
1answer
111 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 ...
0
votes
0answers
81 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. ...
5
votes
2answers
243 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 ...
0
votes
2answers
91 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 ...
0
votes
1answer
930 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 ...
0
votes
1answer
74 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?
0
votes
3answers
2k views

Instruction vs data cache usage

Say I've got a cache memory where instruction and data have different cache memories ("Harvard architecture"). Which cache, instruction or data, is used most often? I mean "most often" as in time, not ...
110
votes
9answers
10k 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, ...
2
votes
1answer
212 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 ...
4
votes
4answers
580 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
5answers
1k 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 ...
5
votes
5answers
4k views

Can multiple CPU's / cores access the same RAM simutaneously?

This is what I guess would happen: If two cores tried to access the same address in RAM, one would have to wait for the other to access the RAM. The second time that each core would try to access ...
2
votes
1answer
240 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 ...
1
vote
1answer
68 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 ...
17
votes
4answers
2k 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 ...
1
vote
1answer
255 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 ...
0
votes
0answers
30 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
votes
2answers
210 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
votes
2answers
389 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 ...
0
votes
1answer
100 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 ...
2
votes
1answer
399 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 ...
9
votes
5answers
250 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
566 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
168 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
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 ...
14
votes
6answers
1k 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
216 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. ...
42
votes
4answers
76k 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
147 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
256 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
232 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
210 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
523 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
votes
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 ...
0
votes
1answer
145 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
767 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
172 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
votes
1answer
355 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
537 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 ...
0
votes
2answers
264 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 ...