Random-access memory (RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time.

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101
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18answers
54k views

I have 16GB RAM. Do I need 32GB swap?

I read many places that the rule of thumb for swap space is to double the amount of physical RAM. However, 32 GB does seem a LOT. Do I need that much? Do I need it at all with this high amount of ...
23
votes
5answers
14k views

Why does Ubuntu only show 3GB of RAM?

I have an Asus G50vt-x5 laptop with 4GB of RAM installed. But Ubuntu 10.10 shows only 3GB of RAM. Why is it only showing 3GB of RAM instead of the full 4GB? output of free command is : neal@ubuntu:~$ ...
17
votes
5answers
30k views

How can I check my RAM and harddrive for errors?

Are there any tools available for this?
35
votes
6answers
56k views

How can I monitor the memory usage?

I have used top to see the memory usage at the moment. But I would like to monitor the memory usage over a period of time. E.g start monitoring and then execute a few commands, and final stop the ...
4
votes
1answer
4k views

How can I check how much space there is left on WUBI versus how much space it takes on my HDD?

Using 11.10 for the record. It would be easiest to do it on the Terminal.
7
votes
3answers
4k views

Why is more than 3GB of RAM not recognised when using amd64?

Why does Ubuntu 10.10 amd64 not addresses more of 3GB ram? Please if somebody knows about that, tell me the solution. My machine is a Toshiba P205-S6287 Intel centrino duo 64 bits procesor and 4GB ...
6
votes
1answer
2k views

Only 3.2 Gb of memory being used on a 64-bit system

I have ubuntu 11.10 64 bit: Linux 3.0.0-12-generic #20-Ubuntu SMP Fri Oct 7 14:56:25 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux I have installed 4 Gb of RAM: $ sudo dmidecode --type 17 | grep -E ...
17
votes
3answers
13k views

What is a segmentation fault?

In Ubuntu I have faced the segmentation fault error many times. What is a segmentation fault and when does it occur?
45
votes
5answers
14k views

Drawbacks of using preload? Why isn't it included by default?

I would like to know what are the drawbacks of using preload? If there would be no downside, preload would be enabled by default, so I guess there are some. Okay you need a bit more RAM, but most ...
18
votes
2answers
6k views

Memory limiting solutions for greedy applications that can crash OS?

I use my computer for scientific programming. It has a healthy 8GB of RAM and 12GB of swap space. Often, as my problems have gotten larger, I exceed all of the available RAM. Rather than crashing ...
10
votes
4answers
9k views

How to permanently enable compressed ram swap? What version to use?

EDIT: In precise there's now zram-config. It's an upstart job compressing up to half of your ram spread over $(number of CPU cores) swap devices. It didn't allways start at boot but issuing sudo ...
8
votes
1answer
4k views

Ubuntu detects only 3.2GB RAM on a 64bit OS [duplicate]

Possible Duplicate: Only 3.2 Gb of memory being used on a 64-bit system I have been running 64 bit version of 11.10 which was upgraded from 11.04 and wasn't a fresh install. I earlier had ...
5
votes
4answers
17k views

Why is the cache in my memory always full?

I have 6GB RAM, i5 2.4GHZ Processor running Ubuntu 11.10. I partitioned my HD so that I have 8GB swap. When streaming online or opening several tabs in Chromium I soon have 4GB Memory in the cache. ...
5
votes
2answers
12k views

How do I make a RAM disk?

I want to make a partition that is made of ram ... Example In windows 7 you can make a partition that is made of ram I have created 1 GB of partition in ram . using Primo RamDisk Is there any ...
7
votes
3answers
11k views

For a 32-bit kernel, what are the pros/cons of PAE vs. non-PAE?

I am using Ubuntu 12.04 32-bit. My kernels are PAE kernels. I know these are the kernels we can use for 32-bit OS which have 4 GB RAM, to utilize all 4GB of RAM. My system is a 32-bit system. So I ...
18
votes
6answers
3k views

8 GB RAM on 64 bit processor using 32 bit Ubuntu

I'm going to repeat the title in a longer word. Can a 32 bit Ubuntu address more than 4 gb of RAM on a 64 bit processor?
13
votes
6answers
45k views

What's the maximum amount of RAM I can use on an specific hardware

I've an Asus U31SD Notebook with an i5-2430M CPU. The Asus site says that the maximum RAM is 8 GB, but Intel's says my CPU supports 16 GB. What is the maximum RAM I can use on this system ...
4
votes
4answers
13k views

Using usbdrive as ram in ubuntu

In windows it is possible to use usb flash drive as a virtual ram. I wonder if it is possible to do so in ubuntu? If it is, how could one do it? [Edit]: I mean Ready boost equivallent for ubuntu. I ...
4
votes
1answer
4k views

Why doesn't Ubuntu detect all of my RAM on 64-bit? [duplicate]

Possible Duplicate: Ubuntu only detects 3.1 GB of ram on Ubuntu 64 bit ISSUE IDENTIFIED: BIOS bug. See dmesg output below. Question is: How to resolve this? Change made since 2.6.32 have ...
14
votes
2answers
9k views

How to create RAM drive?

How do i create RAM drive under ubuntu. And would he automounted at startup?
5
votes
2answers
4k views

Automatically kill a process if it exceeds a given amount of RAM

I work on large-scale datasets. When testing new software, a script will sometimes sneak up on me, quickly grab all available RAM, and render my desktop unusable. I'd like a way to set a RAM limit ...
9
votes
2answers
22k views

How do I clean or disable the memory cache?

After the system starts, in a few minutes my memory cache fills up and it starts using the swap. Here's a screenshot of /proc/meminfo. However, if I can disable this process / clean the cache once ...
5
votes
4answers
16k views

How to impove Ubuntu performance on netbook

Most recent Ubuntu 12.04 seems to be quite nice and Unity (3D/2D) works fine for me, however not on my old Acer Aspire One any more. There was a times, when I switched from Windows XP to Ubuntu and ...
11
votes
6answers
8k views

How to determine where biggest files/directories on my system are stored?

I was wondering how do you know where the largest files in my system are stored. For example--- Disk Space Used: 1GB Java: 500MB Java Percentage: 50% maybe represented in a pie chart. Maybe? I know ...
7
votes
2answers
2k views

How much ram is being used on my laptop?

I have 3987MB of RAM on my laptop. Task (System) Manager says that I am using 700MB of this RAM, whilst the command "free -m" says I am using nearly 1500MB. Which one is correct and why do they show ...
4
votes
2answers
3k views

How to use a compressed ramdisk (ramzswap)? Huge speed gain

Since I don't use my laptop's CD-drive I want to put a small (8 GB) SSD into the CD-drive slot (I'll use a caddy similar to this one). I want to use compressed btrfs on the SSD and put all the data on ...
7
votes
2answers
42k views

How much memory (RAM) should I allocate to the Virtual Machine?

I'm installing Ubuntu in a Virtual Box; my host OS is Windows 7, and I have 6GB of RAM on my system. One tutorial on setting up Ubuntu on a virtual machine (this one, on step 14: ...
6
votes
1answer
2k views

Exclude bad ram bytes

I have 5 bytes (or bits, don't know) of bad Ram. How can I exclude these bytes so my Ubuntu 11.10 don't use them. My PC randomly freez, and when I ran memtest it reported 5 errors.
3
votes
4answers
1k views

what is the nm-applet and why does it take so much memory?

I was wondering why my memory useage was so high, what is this thing that take a whopping 1.2GB of memory. Please and thank you.
3
votes
2answers
1k views

Can I use all my RAM for application data?

I have yet another question about "where is my Linux memory" Question goes: can I use cache for application data? On my laptop I have 1GB ram. Situation after some time of work: browser takes 400MB ...
2
votes
1answer
418 views

Can i automatically kill any application that uses more than a certain percentage of the CPU and/or RAM?

What i need from my computer, now that it's summer at least, should never use a lot of resources - when applications do so it's because of some kind of bug or memory leak. Is there any way to ...
8
votes
9answers
3k views

What are the available browsers for 128 MB of RAM PC?

Running 12.04 with VirtualBox and I set it for 128MB of RAM. I cannot use more than 128MB of RAM. Since the browsers I know like Firefox, Google Chrome and Chromium seem to eat more RAM, could ...
6
votes
3answers
36k views

MicroSD card is set to Read-only state. How can I write data on it?

I have a MicroSD card reader in my notebook. When I insert a MicroSD memory card into it, I can't write any data on it - it's read-only. The same thing happens when I try to do it under root. And I ...
5
votes
2answers
2k views

How to make ubuntu use more RAM?

After 2 weeks of trying, failing, trying again, still failing, I finally got Ubuntu stable and operational. My hard disk is quite old and slow but I have excessive RAM (16 GB 2133 mhz), so I was ...
1
vote
1answer
129 views

/dev/sda1 /boot is full [duplicate]

I know there are a lot of questions like this but I've tried pretty much to understand what to do and failed. By df -h I know that my /dev/sda1 /boot is with 100% use. I'm not understanding what I ...
1
vote
2answers
985 views

Secure shared memory

In my Ubuntu deployment script I have written a function to secure shared memory. For a web server it's important to secure the shared memory to tighten up security. Below you can find the code: echo ...
1
vote
1answer
215 views

Warning when available RAM approaches zero

This is a follow-up to Memory limiting solutions for greedy applications that can crash OS?: ulimit and cgroups are not user friendly, and besides, wouldn't work with applications that spawn separate ...
1
vote
1answer
2k views

Ubuntu only detects 3.1 GB of ram on Ubuntu 64 bit

I am using Ubuntu Linux 64 bit. Recently, I was using Ubuntu 32 bit, and discovered through the command grep --color=always -iw lm /proc/cpuinfo that my processor is capable of 64-bit. The output of ...
18
votes
5answers
20k views

How do I use zRam?

I installed zRam as described on webupd8.org. I installed it from the terminal. Is that all I have to do or do I have to do some configuration or something? Does the zram-enabler do everything by ...
8
votes
3answers
6k views

Computer freezing on almost full RAM, possibly disk cache problem

The problem I think is somewhat similar to this thread. It doesn't matter if I have swap enabled or disabled, whenever the real used RAM amount starts going close to maximum and there is almost no ...
15
votes
2answers
2k views

Is it possible to query maximum ram my mobo takes?

Is it possible to query through Terminal how much ram my motherboard can take? I'm looking to see if i can even upgrade.
5
votes
2answers
1k views

How can I make an existing persistant live USB installation load more of the OS to RAM?

A while back I installed (a permanent installation, not a Live USB) Ubuntu on my USB thumb drive. Unfortunately, the transfer rates are too slow for a smooth and responsive experience, so I'd like to ...
21
votes
4answers
23k views

How to check video memory size?

Is there a way to check the size of the video memory? Specifically, is there one that works accurately for both integrated GPU's as well as PCI/AGP graphics cards? Many integrated GPU's have ...
10
votes
3answers
18k views

Why am I frequently getting this “Cannot allocate memory” error?

I'm using Ubuntu 12.10 with Gnome-Classic. I am getting this error frequently and with almost all programs, big and small. When I try to open them, they don't start, and instead I get an error message ...
7
votes
2answers
6k views

How can I dump all physical memory to a file?

I am using Ubuntu 11.10, and wish to simply know whether I can dump all physical memory and swap, as due to some kernel restrictions, I can't dd /dev/mem, even as superuser. Is there any workaround or ...
5
votes
2answers
797 views

How can I measure how much RAM has been used by a command

I'm trying to measure the memory of a process that I call via the command line (i.e., I want to find out much RAM it takes to for the process ). Is there any command that I can add to the command ...
4
votes
1answer
5k views

Good way to run Java and Eclipse from a ramdisk

It is often suggested to me that to improve the performance of the Eclipse development environment, that I should move the Java JDK/JVM (and possibly Eclipse) to a Ramdisk. I know that the Ubuntu has ...
3
votes
1answer
35 views

How to set a memory limit for a specific process?

I tried to execute mpiexec -16 ... on a 384 GB RAM server, but it induced OOM Killer and was aborted. How can I set a memory limit for mpiexec execution? I know ulimit, but it might affect other ...
8
votes
1answer
4k views

Why is Ubuntu 14.04 using too much RAM..? [closed]

Compiz in earlier versions of Ubuntu took around 60-65 MB of RAM. In Ubuntu 14.04, it is taking around 205-201 MB. And Nautilus took 35 MB of RAM in earlier versions, it is taking a minimum of 65 MB. ...
7
votes
3answers
3k views

Installation only recognizes 3 GB of memory after RAM upgrade [duplicate]

Possible Duplicate: Why does Ubuntu only show 3GB of RAM? I recently upgraded my system from 2 to 4 GB of memory. When I booted into Ubuntu, it's only recognizing 3 GB. I followed some ...