I/O is an acronym for Input/Output, which refers to the mechanism or process for the transfer of information between one system or component and another.

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dd command: Finding read/write throughput of a flash/SD?

I am running petalinux from sd card. And trying to find data copying rate from Sd card and from QSPI flash that is there on the Xilinx Zynq board. As suggested here , I am doing like this: ...
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61 views

Artificially prime buffer cache?

Is it beneficial to artificially prime the buffer cache when dealing with larger files? Here's a scenario: A large file needs to be processed, line by line. Conceptually, it is easy to parallelize ...
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59 views

How to customize or reprogram function of specific keys on my keyboard and the LED on my laptop

When I disable bluetooth on my laptop, the light does not go off and the blinking of the Wi-Fi LED is starting to bother me. Since I sometimes use my laptop in a poor lighting condition an illuminated ...
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60 views

Getting IO privileges in Linux

I have installed flashrom software. When i try to run sudo flashrom command it gives me "Could not get I/O privileges (Operation not permitted). You need to be root" error. Also I tried su command to ...
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1answer
160 views

CONFIG_GPIO_SYSFS makes /sys/class/leds disappear

I have an embedded Linux board I'm working on, with a button and a couple LEDs. By default, I can control the LEDs via /sys/class/leds/redled/brightness However, I have no way to monitor the ...
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81 views

Strange problem with IO or file system or what?

On a SLES 11 SP2 32-bit system I'm seeing a strange problem. It's as if the OS can not open a file from the beginning of the file. Say I have a file that is 200 lines. If I cat or more or vi the ...
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116 views

Determine how much a process is using each disk?

How do I tell how much load a particular process is contributing to each of several available volumes/mounts? It seems that dstat only shows aggregate stats across all processes per disk, and iotop ...
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115 views

Unable to close a Luks partition

For backup purposes, I have "snapshotted" a LVM partition. This partition was crypted so I have opened this Luks partition (snapshot) in order to do my backup. The problem is that I have forgotten to ...
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/dev/sda not appearing after secure erase

I decided to wipe my SSD with a secure erase before installing Arch Linux, since the Arch wiki said that it would improve performance. I followed the instructions listed on the wiki, but now when I ...
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101 views

`crontab -e` sometimes fails with “Creation of temporary crontab file failed”

From time to time crontab -e fails on me on a Ubuntu box. It is the same for all users including the root and crontab -eu <user> under the root. Goes like this on a regular basis, a success here ...
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109 views

jbd2 journal constant i/o

iotop reports a constant i/o about 3% of [jbd2/vda1-8], I think this is the journal manager for ext4. my fstab is: UUID=X / ext4 defaults,noatime,nodiratime 1 1 tmpfs /dev/shm ...
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614 views

find ount what [flush-8:0] is writing

Using iotop, I found out that [flush-8:0] is doing a lot of hard disk activity, which explains the annoying slowdowns. However, I can't figure out what's the actual cause behind this flushing. No ...
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105 views

Shorter timeout on I/O errors MacOS X

How do you set a shorter timeout value for read/write I/O errors on MacOSX? We tend to get a few semicrashed disks and want to rsync the contents to a secure location, but when the file subsystem ...
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0answers
454 views

GNU/Linux, IO performance problems

I have some problems with my system performance. As I was adviced here, I used sar: $sar -u 5 and found out that the problems are caused by a low HDD performance, as I supposed (high %iowait). ...
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148 views

IOMMU causing freezes, disabling causes USB to not work

I'm somewhat new to linux, but I'm running a Xubuntu machine that I recently built. Since I started it up, I had noticed frequent freezes, where both the screen (if plugged in) and any SSH session ...
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149 views

How different is I/O handling of hard disk in AIX and Redhat Linux?

I am running a hadoop I/O workload in redhat linux and have ran that in IBM AIX as well with same underlying hardware, disk and disk configuration. With the default settings on the os redhat linux is ...
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1k views

How to set up ZFS with ZIL and L2ARC SSD?

I have been considering bcache and flashcache. However my friend suggested me something called ZFS. In fact it says that formating disk with ZFS can actually do the exact same thing without kernel ...
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Can ramdisk improve performance when stats show low wait and system cpu use?

I have jobs that do I/O of rates peaking around 200mb/s. On high load (over twice cpu cores) I tried to copy large file and got only few mb/s. Gathered dstat show single digits in wai and sys category ...
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19 views

I2c with 16 bit addresses

So, i'm trying to interface with a device that has 16-bit addresses, and the master I'm using also supports this mode. However since this isn't standard I2C (should be 8-bit addresses) I haven't been ...
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Is swapping the cause of high IO on my box?

I'm running a LAMP stack on an Amazon EC2 micro instance with 616 MB of memory. This seems sufficient to be able to run a few small websites with Apache, MySQL and PHP. I have one Wordpress site ...