IO or I/O is a common shorthand for referring to Input and Output

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VirtualBox: How much disk i/o speed gain will I gain if I have fixed-size hdd image?

I am running virtualbox on win7 with a dynamically allocated hard disk image. It seems to consume a lot of CPU and be slow on hdd activity. I've heard that not choosing a dynamically sized virtual ...
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9 views

Multiple interaction controls on a single computer

I wonder if there is a way to interact with a single computer using two interaction controls.For example,two people must be able to interact with two different application simultaneously on the same ...
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1answer
14 views

What would cause a high `%wa` value when there is nothing performing heavy io?

I have a 92.3%wa value on top right now under linux and when I run iotop -a, I see nothing causing heavy io. What might be the cause of the large %wa value and how can I go about diagnosing this? The ...
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22 views

How to reduce CPU on a Windows Share?

A process writes small files of size 30 KB to the Windows share in an interval of 1- 5 minutes. Another application which is running on a remote Linux machine is accessing those files. As this is a ...
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1answer
24 views

Plot the data collected by sar in ASCII

isag in an "Interactive System Activity Grapher" that "displays the system activity data stored in a binary data file by a previous sar". How do I view the data stored by sar in ASCII on a Linux ...
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1answer
25 views

Does LSF io index report NFS io?

We use SONAS for our filesystem on our cluster and I have noticed that the load on SONAS does not necessarily correlate with the value of io on the cluster nodes when I run lsload -l. Is it possible ...
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How best to iron out disk I/O lag cause?

Running luksCrypt (which I know causes some lag esp. with my -c serpent-xts-plain64 -s 512 -h whirlpool setup) but as of late lag has become very much more noticeable. I use xfs and lvm on this ...
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1answer
27 views

How do i suppress a ssh-add passphrase prompt?

Whenever i run ssh-add in cmd it outputs a passphrase prompt. ssh-add "%~%\.ssh\id_rsa" Enter passphrase for C:\Users\Kristian Welsh\.ssh\id_rsa: I would like to suppress this text to add my own, ...
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Controlling I/O Intesity for a JOB with FIO

I am trying to create a workload profile for a performance evaluation using FIO[1]. This workload profile is based on those presented in the SPC1 specification published by the Storage Performance ...
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3answers
68 views

does IO Port address belong to RAM?

I have been using linux(ubuntu). To communicate with IO devices, IO ports Address are used ex. 0x378 for parallel port. Is IO port address are actual RAM address ? If its not then where it reside ? ...
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1answer
14 views

In a single terminal window capture the command to start a.out 3 times each running as background job

On linux terminal window is there a way i can start a program like ./a.out 3 times each running as background jobs. I was told that IO redirection is helpful.
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1answer
31 views

How can I measure disk writes per file/program over a long period of time

I have an SSD and a hard disk in one computer. I use mountpoints and symlinks to put write-heavy directories (e.g. Downloads) on the hard disk to save on wear on the SSD. I want to find out which ...
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1answer
11 views

Linux redirect output ro earlier agument

Is there a way to redirect output on Linux to a former argument. For example, sort file.txt > file.txt Would there be a way to avoid typing file.txt again?
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1answer
53 views

What is I/O? How does it affect PC operation? [closed]

I see this I/O abbreviation a lot, what does it mean? How does it affect Computer operation?
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65 views

How Memory Mapped I/O works in x86 architecture?

If we use "mov" instruction between the address range of "0x000A0000 - 0x000BFFFF",how cpu understands that the data will be going to video card memory not to main memory?
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224 views

Memory Mapped vs I/O Mapped Input Output

I'm currently reading a computer organization book and i'm so confused about Input/Output mechanism and have lots of questions in my mind. As i understood there are two concepts for communicating ...
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146 views

NFS writes to md-raid extremely slow with busy jbd2

As far as I can remember, this problem appeared after upgrade from Debian Squeeze to Wheezy. The symptom is extremely slow write performance on the server's dmraid exclusively if written via nfs ...
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1answer
341 views

ls -l but not ls --color=never slow on nfs-mounted directory, if simulatenously writing to that directory

when I dump data into an NFS-mounted directory, reading files modes (e.g. ls -l) is several orders of magnitude slower than a plain file listing (e.g. ls --color=never). I would like to understand ...
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37 views

Monitor disk I/O used by specific command

I know that there are various tools for monitoring disk I/O, but I am wondering specifically if there is something equivalent to time for disk usage? For example, I am benchmarking a specific command ...
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1answer
31 views

Windows: Wide Variation in Read Performance

I'm new when it comes to measuring i/o performance. I found a tool called HDTune Pro, which according PCWorld is a good tool for i/o benchmarking. This tool attempted to read 40GB, on the first ...
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1answer
83 views

How can I debug IOZONE over the network?

I'm working on a mac and I have a vm running ubuntu server. I created a file vm_client.iozone that looks like: vm /path/to/test /usr/bin/iozone I have configured iozone to work over ssh using ...
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2answers
254 views

hard drive - How type of I/O access influences access time?

I am trying to better understand how the type of I/O access influences the access time. Can a conventional HDD perform both random and sequential access ? If so why would you want to keep provisions ...
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2answers
45 views

How is it possible for me to hear the audio of multiple different videos on my computer? [closed]

I am reading this book and so far, being in chapter 3, I understand that multiprogramming and multiprocessing allows for faster execution of multiple existing processes/threads. I am reading into all ...
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3answers
104 views

Find which process uses on average the most CPU, Memory and IO on Windows 7

I'd like a way to monitor processes on Windows 7 for average CPU, Memory and IO since last boot. I would love it if it was a nice UI friendly tool that could sort processes by Average CPU, Average ...
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227 views

Can anyone assist me in determining why my ssds are running so slowly please?

I have an MSI GT 680 Gaming laptop that I use for data analysis work. History: Originally I had a pair of 128GB Kingston Hyper X SSDs in the system in RAID 0. I put these in place (when I bought the ...
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1answer
268 views

Why does synchronizing 1.4 TB of data with my Dropbox account result in over 28 TB of IO read?

I tried to sync 4.4 millions of files (totaling ~1.4 TB) with my Dropbox account. I noticed a pretty high amount of IO read (28 TB) when the files were being synchronized, is there any reason why? ...
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140 views

Thinkpad Yoga “Disk I/O Error” (Linux)

My machine is sporadically remounting the SDD readonly due to a "Disk I/O Error". This seems only to happen when I connect to the laptop to a power source or after resuming from suspend. The SSD ...
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1answer
185 views

Mac SSD freezing & I/O error

6 months ago I've added a SSD (Samsung 840 Pro 512GB) on the back of the superdrive and enabled TRIM. It's still as fast as it was when I bought it. Since some days my mac randomly freezes twice a ...
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1answer
7 views

Writing to subfolder is faster than writing to its parent

I use dd to measure write perfomance and observed something strange: writing to /data/emzed2 is faster than writing to /data. This is the way I measured the performance: $ dd if=/dev/zero ...
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78 views

limit/cap total disk I/O to temporarily improve Windows stability on faulty hardware

Is there a way to limit/cap total disk I/O on a Windows 7 system? Processes like git and McAfee sporadically crash with InPageError (for files on different physical drives), seemingly most often when ...
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51 views

List contents of zip archive via stdin

Is there a "magic" way to list the contents of a Zip archive piped in via stdin? For instance: $ some_process_sending_files_in_one_zip_stream_to_stdout | gunzip -l - ... listing of files ... When ...
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810 views

Linux BFQ Scheduler with SSD

In the past I had always been advised by resources that I can get a performance boost when using SSDs by switching from the default Linux scheduler CFQ to one such as deadline or noop. Today after a ...
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57 views

Converting multiple files using programs that accepts stdin and output to stdout

I want to convert a list of files in a directory to another directory using some preprocessing programs. I know I can do this for one file: cat "$INDIR/$file" | ./program > "$OUTDIR/$file" And ...
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89 views

How long does it take for Linux to drop caches?

I run the following to clear cached files from the filesystem/system memory: # echo 3 > /proc/sys/vm/drop_caches I'd like to do this on a scripted basis, so that when I do I/O testing to compare ...
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113 views

Understanding iotop

I have a postgresql select query that consumes only 12% CPU, and little to no memory, but it still takes about a minute to run. I immediately tried to check the IO, using iotop. Sure enough, in ...
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471 views

Optimal cluster size for random I/O

I'm specifically interested in the answer for NAND storage (SD cards, memory sticks). I have a Windows 7 laptop where I run 2 VM's inside VMWare, as well as multiple programs in the host OS. VM disk ...
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1answer
216 views

How to lower I/O priority for file copying operations under Linux Mint?

Whenever I copy files from a disk to another on my personal Linux system, the OS stops responding appropriately, the UI starts behaving erratically, any movies I'm playing will freeze and continue ...
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1answer
100 views

i/o Bus Standards & Device Controllers

I'm really confused about bus standards like ide,ata,sata,pci etc. I have just read this article :When a disk read or disk write occurs, where does the data go? So if we talk about hard disk drive; ...
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42 views

Why do subsequent reads of a multi-gigabyte file run faster?

I have some algorithm test software running on a Windows 7 machine which, when run the first time on any given data file, runs ~3-5x slower than on subsequent runs. Our algorithm simply reads the file ...
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71 views

Can random writes to a non-formatted raw partition from linux corrupt the boot loader?

In brief: suppose I create a non-formatted raw partition on my hard drive, and read and write block IOs to and from it using the standard c interface: open, pread, pwrite, etc. Is there any reason why ...
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1answer
5k views

Difference between port mapped and memory mapped access?

Can anyone explain what's the difference between port mapping and memory mapping, and what having both accomplishes? Why is there port mapped, how does it differ in structure from memory maps, and is ...
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3answers
139 views

What is consuming my disk?

I have a Win8 64bit Dell XPS One computer that continuously has trouble operating because the disk I/O is at >99%! I need a way to find out what is causing this. The Task Manager is no help because ...
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240 views

No performance increase on I/O intensive operation after symlink to ramdisk

We have a system that transforms a set of several thousand multi-MB files. After every step in the transform, it writes the intermediate file to disk. The concept is similar to a scratch disk. We ...
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152 views

circumvent directory I/O error

I recently recovered a large amount of data from a failed external hard-drive with ddrescue, which did an excellent job. However, after running the tool several times and with different options, it ...
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1answer
30 views

Windows 7 printing “io” infinitely in all focused input areas

A few weeks ago, my computer started doing this strange behavior. All I did was click into a window that allowed for user input and the computer began printing "io" over and over again (no error, but ...
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334 views

How can RAM contain a “memory map” if RAM is unaware of the overall system?

This question concerns hardware more than software. Basically, citing from this article on memory maps, it says that: In computer science, a memory map is a structure of data (which usually ...
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1k views

Keep getting i/o error 1117 while trying the file operations

I am trying to copy a huge file (around 50 GB) to external hard drive. I keep getting the I/O error. I tried all things compressing the file, trying to copy to same drive splitting the file using ...
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870 views

<1MBps 4K read/write HDD issue

I bought a netbook, Windows Starter - it seemed really slow right from the start, so I removed all the bloatware, but it remained slow still. So I tested disk I/O with CrystalDiskMark and got 4k ...
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390 views

Getting i/o statistics of a process per file

I have a process of I would like to monitor the i/o with some precision. I know the PID, but I can't really control the way it is started (so I can't really put a pv-like command in between). What I ...
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879 views

Do computers need any input or output device?

Somewhat inspired by an answer I gave about keyboard lights I now ask this: do computers actually need any sort of input (keyboard, mouse, touchpad, scanner, microphone, joystick, etcetera) or output ...