bitPrison.net - Hardware

How to disable chrome caching on Ubuntu?

Jozsef — Tue, 29 Oct 2013 10:06:34 +0000

I bought SSD drive to my laptop, so I decided to minimize write I/O on my system. The less writing is a good idea even you have a HDD. Your system become faster in this way.

There are some good starting point:
https://wiki.debian.org/SSDOptimization
http://askubuntu.com/questions/1400/how-do-i-optimize-the-os-for-ssds

The fake solution

But I would have liked to turn off caching on my browser. I use chrome, and there is no any setting in the UI to turn off caching. In the matter of fact the most supposed solution doesn't work at all. If you turn out the caching on the development tools it just turn off caching while development toolbox is open. But I wanted to find a real solution.

The real solution

Edit /usr/share/gnome-control-center/default-apps/chromium-browser.xml and put --cache-disk-size=1 argument into command tag:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE default-apps SYSTEM "gnome-da-list.dtd">
<default-apps>
  <web-browsers>
    <web-browser>
      <name>Chromium</name>
      <executable>chromium-browser</executable>
      <command>chromium-browser --cache-disk-size=1 %s</command>
      <icon-name>chromium-browser</icon-name>
      <run-in-terminal>false</run-in-terminal>
      <netscape-remote>false</netscape-remote>
      <!--
      <tab-command>false</tab-command>
      <win-command>false</win-command>
      -->
    </web-browser>
  </web-browsers>
</default-apps>

When you click on chromium browser icon the cache size will be 1 byte. So the cache is disabled. (0 means no limit)

Blog categories: Hardware Linux Unix admin

Blog tags: chrome linux ssd performance tuning hardware ubuntu

How to convert your real system to virtual machine?

Jozsef — Fri, 03 May 2013 09:34:44 +0000

I had a real Linux server system that I need to convert into virtual server, because I wanted to sell my old hardware, but I needed the system as backup. This backup is able to run as virtual server. This is a very useful backup method. This tutorial show you how you can convert your whole system into virtualbox system. Virtualbox is a free opensource virtual computer solution from Oracle.

1. Backup your system disk

If you can, put your system disk to another computer. But if you can't do it you can do it the original system.

Backup you hard disk (not just your partition) with the following command:

cd /the/path/of/your/backup
cat /dev/sda >./sda.backup

This command makes you a hard drive image in /the/path/of/your/backup folder.

2. Convert your hard disk image into virtual hard disk

Convert your hard drive backup:

VBoxManage convertfromraw ./sda.backup sda.vdi --format vdi

3. Create new virtual machine

Download, install and start VirtualBox. Push the New button. At the settings of virtual hard disk choose "use existing hard disk" option and select your new sda.vdi virtual hard disk image.

Blog categories: Hardware Linux Unix admin

Blog tags: virtualbox vps backup system admin linux

SATA HotPlug and HostSwap in Ubuntu Linux

Jozsef — Tue, 05 Mar 2013 16:23:46 +0000

Check active scsi devices:

ubuntu@ubuntu:~$ lsscsi
[1:0:1:0]    disk    ATA      SAMSUNG HD103SJ  1AJ1  /dev/sda 
[2:0:0:0]    disk    ATA      SAMSUNG HD103SJ  1AJ1  /dev/sdb 
[3:0:0:0]    cd/dvd  HL-DT-ST DVDRAM GH22NS90  HN00  /dev/sr0 
[5:0:0:0]    disk    Generic  STORAGE DEVICE   9451  /dev/sdd 
[6:0:0:0]    disk    GT-I5700  - Card                /dev/sdc

Now refresh SCSI devices. Use this command to refresh host0 (or host1, host2, host3):

ubuntu@ubuntu:~$ echo "- - -" | sudo tee -a /sys/class/scsi_host/host0/scan

Check the result:

ubuntu@ubuntu:~$ lsscsi 
[0:0:1:0]    disk    ATA      SAMSUNG SP1213C  SV10  /dev/sde 
[1:0:1:0]    disk    ATA      SAMSUNG HD103SJ  1AJ1  /dev/sda 
[2:0:0:0]    disk    ATA      SAMSUNG HD103SJ  1AJ1  /dev/sdb 
[3:0:0:0]    cd/dvd  HL-DT-ST DVDRAM GH22NS90  HN00  /dev/sr0 
[5:0:0:0]    disk    Generic  STORAGE DEVICE   9451  /dev/sdd 
[6:0:0:0]    disk    GT-I5700  - Card                /dev/sdc

HotPlugged SATA HDD appeared on the first line.

Now you can see the partitions on /proc/partitions file:

ubuntu@ubuntu:~$ cat /proc/partitions
major minor  #blocks  name

   8        0  976762584 sda
   8        1     975872 sda1
   8        2          1 sda2
   8        3  963902464 sda3
   8        5   11881472 sda5
   8       16  976762584 sdb
   8       17     975872 sdb1
   8       18          1 sdb2
   8       19  963902464 sdb3
   8       21   11881472 sdb5
  11        0    1048575 sr0
   9        1     975808 md1
   9        0  963902400 md0
   8       64  117245471 sde
   8       65   35656267 sde1
   8       66   57850065 sde2
   8       67    4056412 sde3
   8       68   19679593 sde4

Now I can mount sde[1234] partitions.

Blog categories: Linux Unix admin Hardware

Blog tags: linux system admin

UEFI BIOS Windows 7 installation problem and solution

Jozsef — Sun, 24 Feb 2013 21:53:06 +0000

New ASUS K55 Laptop with UEFI Bios

I have a client who bought an ASUS K55VD laptop. This laptop is coming with Windows 8. But my client had bought a windows 7. So He wanted to use this windows 7 on his new laptop. I had another task. I had to change the HDD to SSD. It sounds easy, doesn't it?

Problems was coming...

I have never seen UEFI BIOS before. I did not think this will be a challenge for me. I tell the truth I wasted a lot of time to install the OS.

Firstly I can not boot any CD under UEFI BIOS. I solve this problem by turning off Security Boot in BIOS Security section.

Secondly the Windows 7 DVD froze during boot under UEFI BIOS. It was a nightmare. Windows 7 installer initializing stopped with a black screen and a white "Loading" text.

I could not start the installer. So I started to play with BIOS. After some hour and some thousand failed booting I found an option. This option is the key to install any Operation System in your laptop with UEFI BIOS. You have to Enable the "Launch CSM" option in Boot section of Bios. CSM means the Compatibility Support Module. Without this you can boot only UEFI mode. Windows 8 in UEFI mode receive serial key from BIOS. Windows 7 in UEFI mode can not boot in my case.

Conclusion

If you want to install any new OS to your PC or Laptop with UEFI Bios just turn off Security Boot and turn on Launch CSM option. Try these options if your OS installer does not boot. This method also works with Windows XP CD and Linux CD/USB Flash.

Blog categories: Hardware

Blog tags: windows laptop UEFI

My new JustCloud storage account

Jozsef — Thu, 19 Jul 2012 09:34:06 +0000

I found a very fast and easy to use online storage solution. My free dropbox account was too small for backing up my files. I mostly backup my most important files with dropbox online storage, but the 2Gb too small for me. I saw the dropbox pro pricing that was almost $10 for 100GB. When I found the JustCloud storage it was less than $10 for unlimited storage. I think it is good offer to me.

If somebody is looking for a good online storage solution, here is JustCloud that secure, fast, and really easy to use. Can you imageine what will you do if your computer chrashed and all your work lost? My collegue has a power supply crash and all his work go away except the drop box. He sould open a justcloud account with unlimited stroage space and backup all system. Now he know it. It would be a good deal. But his hdd has failed and he has no justcloud account. Sad story.

Blog categories: Unix admin Hardware

Blog tags: security backup online storage

Silent PC project

Jozsef — Wed, 24 Dec 2008 23:29:22 +0000

I'm looking for silent PC parts for totally noiseless desktop computer. I will use this PC for software development. This PC need to be silent, fast and video card need to drives 2 monitor over 2 DVI port. I will use 4 monitor with an additional video card in the far future.

Noisy parts are power-supply, CPU cooler, fans and HDDs.

Video card need to has passive cooling with 2 DVI.

Configuration

My new PC configuration will contain follow parts:

ASRock Motherboard with Intel P45 chipset (I haven't known yet which one). I think this motherboards have the best price/performance.
Intel Core 2 Duo E8500 processor (best price/performance let see this benchmark result or let see the full benchmark) in the most case this 45nm CPU defeats most of costly Core 2 Quad.
Sapphire ATI HD-3450 video card with passive thermal solution (totally silent), 512MB DDR2 RAM, 2 DVI output and TV-out. This card is also available in low-profile version. Very cheap and good for programming, browsing.

And the winners are...

Power-supply (14 dBA):
SilenX IXR-55-142 550W
CPU cooler (14 dBA):
NH-U9B (7.9 - 17.6 dBA), but we can change out fan with SilenX IXP-64-14T 92x92x25mm thermistor fan (6 - 14 dBA depend on CPU therm). This fan is innovative. If original Noctua fan with Ultra-Low-Noise-Adaptor is enough strong for holds therm low, I will not change to SilenX thermistor fan.
Fans (max. 11dBA):
If need I will use SilenX fans. These quiet fans have ideal performance.
HDD (max. 20dBA):
I will use Samsung notebook HDD (noise level: 17-21 dBA). SSD is very costly but perfect solution the notebook hdd slower than normal HDD but more quiet.

This is just a plan, to be continue... :)

If you know quieter parts, please comment it.

Blog categories: Hardware

Blog tags: hardware modding silent PC