Questions tagged [io]

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

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Unexpected latency reading from /dev/zero

I am currently investigating IO issues in some hosts and encountered a completely unexpected behavior for me: reading 1M from /dev/zero takes over 100ms While testing the drives I used the following ...
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118 views

PCI device: who assign I/O address range ? (Bios, Driver or Opeating System)

Who assign I/O memory adress range ? I'm a little confused, I don't know if this address range is assigned by Bios, Driver or Operating system. I have a problem with an address range of a device and ...
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Virtualbox VDI disk performance issues

I'm running Virtualbox 6.1 server on an Ubuntu 20.04 host - 64 bit, lots of CPU and RAM. A Virtualbox VM is running Ubuntu 18.04, 32 bit. The OS is installed onto a vdi image. Things have been running ...
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Which HDD track is the fastest? [duplicate]

I was told by a friend, that the (physically) innermost track on an HDD platter will read and write the fastest. But I think to myself that the outermost track must have more capacity for blocks and ...
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HDD I/O fast at first but gradually decreases? [duplicate]

I was benchmarking my WD 500 GB HDD in Ubuntu Disks several times and saw that the read speeds started at 140 MB/s, but it consistently would gradually decrease by a few MB/s with seemingly no floor. ...
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I/O range out of bounds: this device cannot find enough free resources (error code 12)

We have two types of machines (old and new) very similar : same motherboard, same Windows 7 OS, same capacity, ... with a slight difference in the BIOS version. The driver and the PCI device work well ...
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How to log disk i/o per user

In a program that I am coding, I want to calculate disk i/o (read and write operations, in bytes) during any specific time duration for each user in a Linux machine. I think there is no straight ...
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unclear semantics of some fio options

I am doing some raw disk tests using fio. I found some behaviour are not clear when I specify --filename=/dev/device_name and --direct=1. Could please help me to explain it? (1) default ioengine is ...
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High percentage of IO in iotop

I have a problem with a very slow process (mongod), so I downloaded iotop to see how is my drive going. I can see a very high percentage in the IO< column, constantly about 70-99%. Can someone ...
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1answer
31 views

Writing keypresses to SSD & wear leveling

I am planning to write an application that tries to write as much to file as possible as to never lose any significant amount of data. It will write every key stroke including micro or even nano-...
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1answer
34 views

why keyboard input lags while using Zoom app

Every time I am using Zoom App or Google Meet, The keyboard input is delayed terribly (about 3s+) while typing in any kind of application. I tried to reinstall Zoom again, deactivate my antiVirus (...
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26 views

Find out which files a process is writing to

I have this very annoying problem with Firefox for months where its CPU usage jumps to over 24% after a while when idle. Any official troubleshooting has lead to no positive results (tried to reset, ...
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819 views

IO shield is causing my motherboard to not align with case standoffs

I have a very quick question regarding the IO shield in my PC build. I'm a complete beginner when it comes to this, so this might be a silly question. I've recently started building a computer but I'...
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1answer
500 views

Why does the RTX IO in the Nvidia GeForce RTX 30 Series use any CPU at all even though the information flow from the storage to the GPU?

I saw in the 2020-09-01 Official Launch Event for the NVIDIA GeForce RTX 30 Series that the RTX IO in the Nvidia GeForce RTX 30 Series allows the GPU to directly access the storage (SSD) without ...
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Why does `find | md5sum` stop my desktop being responsive?

When I run: find $HOME -type f -print0 | xargs -0 md5sum > /tmp/home-md5sums my Ubuntu 18.04 GNOME desktop becomes very unresponsive: mouse actions and keystrokes take several seconds to register, ...
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VHDX I/O performance. Is it slower?

Does storing data in a VHDX virtual drive make it slow to read and write? Or is it the same as copying file withing the same physical drive?
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1answer
42 views

Blktrace missing I/O events

I'm using blktrace to capture the traffic that goes to my device and have been dealing with some painful issues. Wondering if you guys can confirm/correct my findings. Seems like blktrace is missing ...
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119 views

How do I set /sys/block/X/queue/scheduler on Ubuntu 18.04 with HWE on startup

I am running Ubuntu 18.04 (Bionic) with the HWE stack installed. This means I have the 5.3 Linux kernel running. In older versions of the kernel, apparently passing elevator=noop when GRUB starts the ...
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No input devices working after startup

It's a normal day. I start my PC and try to login and BAM. Both my keyboard and mouse are not working. The devices itself are working fine (I can see the lights and stuff) but Windows somehow doesnt ...
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2answers
53 views

rm -rf foo_dir takes a long time

I have a directory ./aggregated/ in which I have 7550 sub-dirs each containing 250 files. aggregated has 5.5GB in total. I've tried deleting aggregated via rm -rf aggregated and it is taking hours. ...
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99 views

Poor and strange disk performance with VirtualBox (macOS host, Windows 10 guest)

I have VirtualBox 6.1.4 running on macOS Mojave. I'm working with a Windows 10 guest and it seems I have some performance problems with disks. Testing with Aja System Test, on macOS I see numbers ...
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43 views

How is I/O encryption handled in modern systems? [closed]

First: I've struggled with the question on which stackexchange to post this question since it involves OS knowledge, hardware knowledge but probably also other CS fields. Suggestions for a better ...
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140 views

Problems accessing disk after IO tests

I am having problems when accessing my home folder, or generally anything that is on my HDD (I also have an SSD which seems to work fine) in my ubuntu (18.04.4) workstation. :/$ df -h Filesystem ...
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1answer
54 views

What's happening when I create a file in a “NTFS compressed” directory?

What's exactly happening? The files appear in the UI as compressed. Is it? If so, is it written twice (like, uncompressed version of the new files is stored, as a buffer, and compressed then (so ...
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41 views

How to determine the duration for which a file was accessed/modified a program?

I would like to measure the speed of encryption performed by a utility on a Windows 10 box. Since there are no other ways in the utility itself to do this, I would like to know if I can determine how ...
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1answer
59 views

Process ntoskrnl.exe CPU usage jumps from 1% to over 40% precisely when using I/O

the problem occurs with the following system. Device: Lenovo Ideapad 730S - Windows version: 10.0.18362 Build 18362 So ntoskrnl.exe is running just fine as long as all the USB-C ports are left free. ...
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how to install kernel module for blk_mq's io schedulers?

I have recently changed single queue to multi queue on my oracle server. This server is oracle linux 6.10 (4.1.12 kernel). I realize there is no any io scheduler for blk_mq alse show the /sys/block//...
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which io scheduler is recommended when use the blk_mq block layer with oracle database?

I have oracle Linux 6.10 with 4.1.12 kernel. I have recently moved from the legacy block to the blk_mq block. But all SCSI devices have show io scheduler is none. I have researched but I didn't find ...
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505 views

Cannot diagnose slow disk read speed, bottleneck, in Ubuntu

I have the same processes running on 2 (or more machines) for which we notice a massive slow down in disk i/o on some machines. The PCs have very similar hardware (I am happy to post dmidecode if ...
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1answer
218 views

Is it safe to use one server fd in multiple epoll event loops in different threads?

I have one server fd, and several threads with epoll event loop in each of them (different epoll_fd's). Is it safe, if I would add this fd to every event loop? Is it true, that only one of them would ...
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147 views

Pipe stdout of two programs to each other

I have two programs, one of them prints something first, they need to communicate with each other with their standard IO. Is there a way in Bash to pipe stdout of two programs to each other? I know I ...
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Making MsMpEng.exe disk access be nice

MsMpEng.exe disk accesses are making my system unusable. Since this process is critical for system security, it is unreasonable to disable it. Moreover, as it is provided by the OS vendor, and ...
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924 views

Very high disk usage due to reading from CbsPersist…log

My personal laptop is Windows 7, Dell, 8 CPU Cores and 8GB of RAM. It operates very slowly, especially when launching software, and I think especially when starting up (but not only). Looking at ...
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1answer
3k views

Trying to write to /sys/class/gpio/export – write error: Invalid argument

I have an Intel aaeon upboard and I want to use its GPIO pins. To do that I'm trying the below code: echo 17 > /sys/class/gpio/export But when I run it, this is what I get: -bash: echo: write ...
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1answer
139 views

Where do Docker containers and Kubernetes pods write to disk in absence of a volume?

General question about the internals of Docker and containers running in Kubernetes when using the Docker engine. Docker containers are ephemeral, meaning that if a container is destroyed, any data ...
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869 views

Unable to mount DVD - unable to read superblock

I bought a Documentary DVD online, but when I inserted the DVD into a Windows machine, nothing happened. So, I tried with Ubuntu, and same thing happened. When I checked dmesg after I inserted the ...
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1answer
172 views

Does 'Write cliff' phenomenon only happen to SSD disks?

First of all, I am new to disks, I just know the basics. I am trying to improve performance of a software with heavy I/O and I need to understand how my SAS disks work in terms of read and write speed....
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529 views

CPU Burst or I/O Burst

If a process that currently is being executed faces an I/O Burst, will the next available process gain the CPU burst or will the processor wait until the I/O Burst of the first process finishes to ...
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2answers
144 views

What's the use of providing number of partitions when partitioning a hard disk?

I'm trying to partition my hard disk to make it usable. I'm following the steps given in this link to partition my hard disk. I'm doing this by providing the number of partitions as 1 and choosing the ...
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121 views

IOException - Leiningen REPL crashing while typing

I'm coding in Clojure and have been using Lein's REPL thoroughly. But recently it's been crashing while I'm typing, especially while opening or closing maps or parenthesis, with the following error ...
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1answer
31 views

How to save output of python-swiftclient to file when dowloading a directory?

When I download files from a cloud with python-swiftclient sometimes I get errors like this one: Error downloading object 'uploads/1/image.png': Object GET failed: https://orbit.brightbox.com/v1/...
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What prevents my RT thread from working?

I have some data acquisition application running under Linux 2.6.37 on DM8148 with TI Linux. I have two threads: thread named IDE, scheduled as SCHED_RR, prio 114 (75), which collects data from HW ...
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1answer
467 views

The request could not be performed because of an I/O device error

A few weeks ago something bad happened to my OS (Windows 10). In my laptop I have SSD with OS and HDD for data (cd drive slot). I usually hibernate my PC instead of shutting it down. I also have a bad ...
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1answer
859 views

iostat + how to solve latency on disks

we use iostat -x and check for the await column - per device it shows the total time spent waiting plus the actual handling of the request by the disk iostat -yzx 5 Device: rrqm/s wrqm/s ...
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1answer
58 views

Can Operating Systems handle shift, ctrl and alt key signals separate from the keyboard?

The basic problem is this: I have a mini keyboard I'm using for a Raspberry Pi project, and since there is only one shift, ctrl and alt key apiece, that means combinations on the left side of the ...
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1answer
24 views

Disk write issue but no error detected

I'm using a 3TB western digital red disk on my desktop pc (windows 10) and smart info says it's been powered on for nearly 1000 days, I never had any issue with it before but now I'm having some ...
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56 views

Why firefox behaves so weirdly/annoying?

Occasionally FF starts very heavy activities, performing huge amounts of I/O (On my HDD) and considerable CPU usage for a long time (More than 10 minutes is really normal for it) that there is no ...
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1answer
83 views

Which filesystems reuse unchanged data blocks on write?

Let's say I open and read an existing file of N blocks where N > 1. Then I change data which resides within the boundaries of one - 1 - block. On writing back the actual data, presumably one of ...
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2answers
1k views

What are the relations between IO ports and registers in a device controller? [closed]

Do the following two references give different claims on the relations between IO ports and registers in a device controller? What are their relations actually? Does the following quote from https://...
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2answers
63 views

Are interrupts used to signify that output is ready or input has completed? [closed]

Operating System Concepts says: During I/O, the various device controllers raise interrupts when they are ready for service. These interrupts signify that output has completed, or ...

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