Sarath

Sarath

Sarath

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Monday 7 August 2017

Disable Mouse Cursor in Touch Screen embedded Linux with X11

August 07, 2017 2


Disable Mouse Cursor in Touch Screen devices


When working with touch-screen interfaces or embedded systems you often don't want or need the mouse cursor.
 Most of the information I found about this specific topic described people either trying to use `xsetroot` or loading a cursor theme with all the cursors set to transparent. The following is, I believe, the correct solution.

Simply pass the nocursor option to the X server when you start it. There are a million ways to start X-Windows. 
I will list four variations. When using `startx` or `xinitrc` you can put these options in .xinitrc.

For my case i did ,
Edit : /etc/X11/Xserver

#!/bin/sh#XSERVER=/usr/bin/Xorg. /etc/profileARGS=" -br -pn  -nocursor"
DISPLAY=':0'exec xinit /etc/X11/Xsession -- $XSERVER $DISPLAY $ARGS $*

save the file and restart you machine.


Xorg -nocursor
X -nocursor
xinit -- -nocursor
startx -- -nocursor
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Tuesday 1 August 2017

Replacing the Linux logo with your own Logo

August 01, 2017 3

1 Create your own logo file



Create your logo in a .png format (logo.png), and run the following to convert it to a 224 colors PPM formatted image file named logo_linux_clut224.ppm :



 

2 Convert your logo file to PPM format


You needed to install netpbm and after that execute this steps:



$ sudo apt-get install netpbm





once you installed, follow below steps,



sarathkumar@Sarathkumar-RND:~/yocto_kernel_BBB/logo$ convert logo.png temp.ppm



sarathkumar@Sarathkumar-RND:~/yocto_kernel_BBB/logo$ ppmquant 224 temp.ppm > 

temp1.ppm 
ppmquant: making histogram...
ppmquant: 4251 colors found
ppmquant: choosing 224 colors...
ppmquant: mapping image to new colors...

sarathkumar@Sarathkumar-RND:~/yocto_kernel_BBB/logo$ pnmnoraw temp1.ppm > logo_linux_clut224.ppm



Steps:

convert logo.png temp.ppm
ppmquant 224 temp.ppm > temp1.ppm
pnmnoraw temp1.ppm > logo_linux_clut224.ppm 




Your own logo ready now. logo_linux_clut224.ppm is replacing exiting Linux penguin logo.


3 Replace the default logo file in the Linux source



Using the Linux source code directly

Follow the "Build Linux from source code" guide to get the Linux kernel source tree.

Copy your logo_linux_clut224.ppm file to {kernel_source}/drivers/video/logo/logo_linux_clut224.ppm overwriting the original logo.

Configure your kernel and enable the default logo instead of the your logo: Device Drivers -> Graphics support -> Bootup logo -> Standard 224-color Linux logo (Symbol: LOGO_LINUX_CLUT224)

Now you can build the kernel source and try to boot your kernel with newly compiled image with your own logo.




------------------------------------------------------------------------------------------------------------------------



If you want to create a different configuration for your own logo rather than overwriting the default one,  

follow below steps,

1.Edit : {kernel_source}/drivers/video/logo/Kconfig




config LOGO_CUSTOM_CLUT224           
        bool  "224-color Variscite Linux logo"             
        default y


/*  add above three lines before endif # LOGO of the file   */

2. Edit : {kernel_source}/drivers/video/logo/Makefile

obj-$(CONFIG_LOGO_SUPERH_CLUT224) += logo_superh_clut224.o
            obj-$(CONFIG_LOGO_CUSTOM_CLUT224) += logo_custom_clut224.o
obj-$(CONFIG_LOGO_M32R_CLUT224)+= logo_m32r_clut224.o
/*  insert the above green color line between those two lines of this file   */


3. Edit : {kernel_source}/drivers/video/logo/logo.c



#ifdef CONFIG_LOGO_SUPERH_CLUT224

/* SuperH Linux logo */

logo = &logo_superh_clut224;

#endif
 #ifdef CONFIG_LOGO_CUSTOM_CLUT224   
/* Custom Linux logo */   
logo = &logo_custom_clut224; 
#endif
#ifdef CONFIG_LOGO_M32R_CLUT224
/* M32R Linux logo */
logo = &logo_m32r_clut224;
#endif

/*  insert the above green color lines  in-between those           colour section of t, this file   */


4. Edit : {kernel_source}/include/linux/linux_logo.h

extern const struct linux_logo logo_spe_clut224;

           extern const struct linux_logo logo_custome_clut224;


/*  insert the above green color line below that         colour  lines of this file   */



5. Rename the Logo file  :

      rename the newly create logo file name from logo_linux_clut224.ppm  to   logo_custom_clut224.ppm

Configure your kernel and enable the your custom logo instead of the Linux logo: Device Drivers -> Graphics support -> Bootup logo -> Standard 224-color Linux logo (Symbol: LOGO_CUSTOM_CLUT224).




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Saturday 25 February 2017

An Introduction to Linux Basics

February 25, 2017 0

What is Linux ?

Linux is a free, open-source operating system. Linux has been under active development since 1991. It has evolved to be versatile and is used all over the world, from web servers to cellphones.
However, newcomers to Linux may find it difficult to approach the structure of an unfamiliar operating system.
This guide gently introduces key terminal skills and equips newcomers to learn more about Linux.

The Terminal

For most of the time you access a cloud server, you'll be doing it through a terminal shell. The shell allows you to execute commands on the droplet.
All administrative tasks can be accomplished through the terminal. This includes file manipulation, package installation, and user management.
The terminal is interactive. You specify commands to run. The terminal outputs the results of those commands. Executing any command is done by typing it and pressing Enter.

Linux filesystems are based on a directory tree. This means that you can create directories (or "folders") inside other directories, and files can exist in any directory.
To see what directory you are currently active in:
pwd
This stands for "print working directory", and will print the path to your current directory. The output can look similar to this:
/home/foo
This means that your current active directory is foo, which is inside home, which lives in the root directory, /.
To see other files and directories that exist in your current working directory:
ls
This will give you a list of names of files and directories. To navigate into a directory, use its name:
cd <name of directory>
This will change your new current working directory to the directory you specified. You can see this with pwd.
Additionally, you can specify .. to change to the directory one level up in your path. To get back to your original directory:
cd ..
We can also create new directories in our current working directory. For example, to create a new directory called bar:
mkdir bar
Then we can
cd
into bar if we want. We can also delete bar if we no longer find it useful:
rm -d bar
rm -d
will only delete empty directories.

File Manipulation

Files cannot be used with
cd
(it stands for "change directory").
Instead, we can view files. Say we have a file baz in our current directory:
cat baz
This will print out the entire contents of baz to the terminal.
With long files, this is impractical and unreadable. To paginate the output:
less baz
This will also print the contents of baz, but one terminal page at a time, beginning at the start of the file.
Use the spacebar to advance a page, or the arrow keys to go up and down one line at a time. Press q to quit out of less.
To create a new file called foobar:
touch foobar
This creates an empty file with the name foobar in your current working directory. The contents of this file are empty.
If we decide foobar isn't such a good name after all, we can rename foobar to fizzbuzz:
mv foobar fizzbuzz
mv
stands for "move" and it can move a file or directory from one place to another.
By specifying the original file, we can "move" it to a new location in the current working directory, thereby renaming it.
It is also possible to copy a file to a new location. If we want to bring back foobar, but keep fizzbuzz too:
cp fizzbuzz foobar
Just as you guessed,
cp
is short for "copy". By copying fizzbuzz to a new file called foobar, we have replicated the original file in a new file with a different name.
However, what good is a file if it contains nothing? To edit files, a file editor is necessary.
There are many options for file editors, all created by professionals for daily use. Such editors include vim, emacs, nano, and pico.
nano is a perfectly suitable option for beginners. It is easy and simple to use, with no bells or whistles to confuse the average user.
To edit text into foobar:
nano foobar
This will open up a space where you can immediately start typing to edit foobar.
To save the written text, press
Ctrl-X
then y. This returns you to the shell with a newly saved foobar file.
Now foobar has some text to view when using
cat
or
less
.
Finally, to delete the empty fizzbuzz:
rm fizzbuzz
Unlike directories, files are deleted whether they contain content or not.

The Filesystem Hierarchy Standard

Nearly all Linux distributions are compliant with a universal standard for filesystem directory structure.
The FHS defines clearly determined directories for different purposes.
The symbol / is used to indicate the root directory in the filesystem hierarchy defined by the FHS.
When a user logs in to the shell, they'll be brought to their own user directory in /home.
The FHS defines /home as containing the home directories for regular users. (root has its own home directory in /root, also specified by the FHS.)
Because default, common-sense locations are provided for many different kinds of files, organisation of files for different purposes is simplified.

Permissions

On a system with multiple user accounts, determining who is allowed to interact with what files is important.
Linux supports unix-style file system permissions, which restricts who can read and write certain files.
Permissions are an expansive and profound topic in 

A Culture of Learning

So far, this guide only serves to teach the basics of toddling around in a Linux environment. But finding your way around the Linux environment requires dedication and a curious mindset.
When you have a question about how to accomplish a task, there are several avenues of instruction you can turn to.
First and foremost, Google and DuckDuckGo are invaluable resources. Odds are that if you have a question, many others have already asked it and had the question answered.
Your immediate instinct should be to look for the answer through those search engines.
When your question has to do with any Linux command, the manual pages offer detailed and insightful documentation for nearly every single command.
To see the man-pages for any command:
man <command>
For instance,
man rm
displays the purpose of rm, how to use it, what options are available, examples of use, and more useful information.
Gaining the information you seek is an essential skill, which will sustain your Linux career for as long as you stay devoted to a time of learning.

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Saturday 6 April 2013

System Restore to restore Windows XP to a previous state

April 06, 2013 0

To use System Restore to restore Windows XP to a previous state, follow these steps:

  1. Log on to Windows as an administrator.
  2. Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore.
  3. On the Welcome to System Restore page, click to select the Restore my computer to an earlier time option, and then click Next.
  4. On the Select a Restore Point page, click the most recent system restore point in the On this list, click a restore point list, and then click Next.
    Note A System Restore message may appear that lists configuration changes that System Restore will make. Click OK.
  5. On the Confirm Restore Point Selection page, click Next. System Restore restores the previous Windows XP configuration, and then restarts the computer.
  6. Log on to the computer as an administrator. Then, click OK on the System Restore Restoration Complete page.
If you successfully restored your computer to a previous state and the computer runs as expected, you are finished.


If the restore process completed successfully but the computer does not run as expected, go to the "How to undo a system restoration after you perform a System Restore" section. If you received an error message, and the restore process was not completed, or if you cannot run System Restore, go to the "Next Steps" section. . . 
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Global Positioning System (GPS) . . .

April 06, 2013 0

The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil and commercial users around the world. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver.
The GPS project was developed in 1973 to overcome the limitations of previous navigation systems,[1] integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. GPS was created and realized by the U.S. Department of Defense (DoD) and was originally run with 24 satellites. It became fully operational in 1994. Roger L. Easton is generally credited as its inventor.
Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS system and implement the next generation of GPS III satellites and Next Generation Operational Control System (OCX).[2] Announcements from the Vice President and the White House in 1998 initiated these changes. In 2000, U.S. Congress authorized the modernization effort, referred to as GPS III.
In addition to GPS, other systems are in use or under development. The Russian Global Navigation Satellite System (GLONASS) was developed contemporaneously with GPS, but suffered from incomplete coverage of the globe until the mid-2000s. There are also the planned European Union Galileo positioning system, Chinese Compass navigation system, and Indian Regional Navigational Satellite System. . . 

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Wednesday 3 April 2013

Windows 9

April 03, 2013 0



The fact that Microsoft is working on Windows 9 is no surprise, however so far we've received very little information on the next version of Microsoft's OS as most of the attention thus far has been focused onWindows Blue. According to Win8China, who have provided a number of Windows leaks in the past, Microsoft are likely preparing Windows 9 for a tentative November 2014 product launch, with a beta to be available in January 2014.
Now of course this is just a rumor at this stage, however a release scheduled for late 2014 does fit with what we've heard in regards to a yearly OS update cycle for Windows. Windows Blue will be an upgrade to Windows 8 that will be launched this year, while a full version upgrade will come the following year, and naturally November is the perfect time ahead of the holiday season.
What will come in Windows 9? Well we're not quite sure at this stage as its release is some time away, although Win8China believes improvements to touchscreen support will be included, which wouldn't surprise us at all. The site also says that a mobile version of Windows 9 is in the works, which likely is referring to Windows Phone 9 - a product almost certainly also in the works . . . .
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Tuesday 26 March 2013

Office 2013 review . . .

March 26, 2013 0

Office 2013 review

We go in depth with the finished version of Office 2013

Microsoft Office has changed. It's not just that Office 2013 gets the Windows 8 treatment, with a touch-friendly interface and a sparser look, as well as new features in every application.
Office is also going to the cloud, with subscription pricing, on-demand installation and automatic syncing of settings and documents you save in the cloud – if you want to pay for it that way.
As usual, there are multiple versions of Office 2013, but this time around the different editions are not just about whether you're using them at home or in a business or which applications are included.
Office 2013

Buying Office 2013

Even if you decide you want to buy a pay-for-it-once-and-keep-it copy of Office 2013 in a box, you won't find a DVD inside – just a product key to unlock the software you download. (Buyers in "developing countries with limited internet access" can still get a DVD, but that's not an option in the UK or US.)
If you prefer to pay an annual subscription to get extra features, Office 365 editions let you download the Office 2013 applications onto multiple PCs (or share them with your family).
For home users, there are four options. Buy the boxed software and you can put it on one PC. Office Home and Student 2013 with Word, Excel, PowerPoint and OneNote costs £109.99/$139.99; Office Home and Business 2013 adds Outlook and costs £219.99/$219.99. Office Professional 2013 has the full set of programs for £389.99/$399.99; Word, Excel, PowerPoint, OneNote, Outlook, Access and Publisher.
Then there's the new subscription version that Microsoft released this week, Office 365 Home Premium, which costs you $99.99 a year for Word, Excel, PowerPoint, Outlook, OneNote, Access and Publisher.
That's good value if you share it with the family; up to five people in the same household can have their own installations of Office on their PC or Mac at the same time (for the Office programs that run on a Mac – and Mac users get the current version of Office for Mac until a new release comes along in the future). And when the next version of Office comes out, you'll get it on the same subscription.
All five people get an extra 20GB of storage on SkyDrive to keep documents on and 60 free Skype world calling minutes a month (which can be calls to a landline or a mobile and from your PC or from a smartphone with Skype installed).
Office 2013
You can download the Office programs temporarily on another PC if you're away from your usual PC (even if it already has another version of Office installed). So if you have a document on a USB drive or on SkyDrive that you need to edit on another PC, and using the Office Web Apps from SkyDrive doesn't provide of the features you need (like seeing revision marks in a tracked document you're collaborating on), you can use Office on Demand to get the full version of Word in just a few minutes.
You manage all this from the revamped Office.com and there's a link to your account there in the ribbon of all the Office applications. (To activate the Skype minutes you have to link your account to the Microsoft account you're using for Office 365, which can be done on the Office.com site.)
You also get a list of your recently edited documents, which helps when using Office on Demand to give it a fresh edit.
If you're at college or university (or you teach at one) it's possible to get Office 365 University on a four-year subscription for $79.99 that you can use on up to two PCs or Macs.
Also, as you might expect, Office 2013 and Office on Demand only run on Windows 7 and 8, not on XP or Vista.
Office 2013 ribbon

Office for business

Although Office 365 Home Premium might also sound like a great deal for a small business, it's not licensed for commercial use (Like the Windows RT versions of Office 2013) unless you already have an Office business licence. Instead, you need one of the Office 365 business subscriptions, available from February 27.
These will include the new Office 2013 versions of Exchange, SharePoint and Lync Online, which are already available to run on your own servers. It's taking some time for Microsoft to upgrade Office 365 to run these new server versions, which explains the later availability (there are a number of issues in SharePoint the Office 365 team is working on). We've tried these out with the Office 2013 applications (and we looked at SharePoint Online 2013 in more detail here.
Office 365 Small Business Premium includes Word, Excel, PowerPoint, OneNote, Outlook, Access, Publisher and Lync. The annual $149.99 subscription lets you run them on up to five PCs or Macs at once (again, you can use Office on Demand to download Office to any PC you're using temporarily, and you get regular updates and new features).
You can host online meetings with audio and HD video conferencing in Lync and run a public website on SharePoint, plus you get Exchange with a 25GB mailbox for each user and SkyDrive Plus storage on SharePoint.
That gives you 10GB of secure cloud storage with an extra 500MB for each user, but you can choose how the storage is allocated between users and you can control how they use it – like forcing them to encrypt confidential documents.
Office 365 ProPlus (short for Professional Plus), is aimed at midsize businesses (10-250 employees) and includes the same desktop Office software as Small Business Premium. But it also has tools for business intelligence, consistency checking to Excel and automated deployment, as well as more options for the SharePoint, Lync and Exchange Online services.
Office 365 Enterprise has the full Office 2013 set of features in the desktop software and SharePoint, Lync and Exchange Online services, like archiving, legal hold, Data Loss Prevention and rights management to protect confidential information.
If you're looking for five or more copies of Office 2013 and you don't want the Office 365 services at all, you can buy Office Standard 2013 (with Word, Excel, PowerPoint, OneNote, Outlook with Business Contact Manager, Publisher, the Office Web Apps and limited Lync, SharePoint and rights management services) or Office Professional Plus 2013 (with the full range of desktop Office programs and server features) through volume licensing.
We've already looked at the final (RTM) version of the Office 2013 applications. Now we've been able to try out the Office 365 Home Premium service with the new Office.com site, where you can download some of the new Office apps (although the apps for Outlook won't work until you have Exchange 2013).

Installing Office 2013

With any of the Office 365 subscription version of Office 2013, you don't have to worry about downloading and saving a large installer for Office (or even about uninstalling previous versions of Office, apart from Outlook). Whether you start the download from the Office 365 site or you try to open an Office document on a PC that doesn't have Office, the programs stream from the cloud.
This is a much improved version of the click-to-run virtualisation that Microsoft has used for the Office trial versions for a few years, which enables you to start using the applications just a few minutes after you download them. You don't have to wait for the full download; you can use the first features as soon as they download and if you click on a tool that hasn't yet downloaded, the installer will get that next.
Office 2013 subscription
The streaming happens quickly enough that the slideshow of new features you can watch while the other applications install is actually running in PowerPoint (and you don't have to watch it unless you want to).
You do have to pick a few options like the language to use for Office, the design you want to see in the ribbon and whether you want to send Microsoft anonymous telemetry about how you use Office. You can also fill in your Microsoft account details, which Office uses to sync settings like recent documents from SkyDrive, email accounts, custom AutoCorrect entries, the list of your Office Apps and the buttons you add to the Quick Access Toolbars.
Office 2013
It might seem odd to sign in with your Microsoft account on the Office.com site and then get asked for it during installation, but this is how you share the subscription; use the account that's paying for the licence to log in to Office.com, start the download, then sign in with the account of the person who will be using Office on each PC.
It's all very simple and very well thought out. This is your personal version of Office, on any PC, a lot faster. If you've downloaded the Customer Preview of Office 2013 you've tried this already. (The traditional Office desktop installer uses similar technology so the installation is faster there as well.)
Office 365 Home Premium adds several more designs that you can use to decorate the Office ribbon, including doodled circles, lunchbox sandwiches, pens and pencils, cartoon fish and spring leaves. It's a little odd, but there's something for most tastes (including a blank ribbon).
Once the programs are installed you can also choose from three Office themes (click your account picture at the top of the screen and choose Account Settings or open File > Account. The default white gives you the clean look you might have seen in the Customer Preview or in Office RT; pale Ggrey adds a light tint to the ribbon and other panes and dark grey is a high contrast colour scheme that puts a mid grey on the ribbon and panes and replaces most of the accent colours in each application with a very dark grey.
If you're not a fan of the new Windows 8 look, experiment with the themes to see if an alternative changes your mind . . . .
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Saturday 23 March 2013

Android 5.0 [ Key Lime Pie ]

March 23, 2013 0
Android 5.0 Key Lime Pie release date, news and rumours
Android 5.0 Key Lime Pie has started baking

Google's showing no signs of slowing its pace of Android development, with Android 4.0 appearing on the Galaxy Nexus late in 2011, followed in July of 2012 by the Android 4.1 Jelly Bean release that arrived powering the super Nexus 7.
But, forward-looking, update-obsessed people that we are, we can't help but imagine how Google's going to maintain the pace of innovation in its next version of its mobile OS, Android 5.0.
All we know so far is that Google's working away on the K release of Android, which it's developing under the dessert-related codename of Key Lime Pie. Regarding the version number, it's likely that the Key Lime Pie moniker will be given to Android 5.0. We thought we might find out on 29 October 2012 but as yet there is no official word from Google.
So now as we wait on official news of the Android 5.0 release date and features, we can start to pull together the Key Lime Pie rumours from around the web, with the first sighting of Android 5.0 on a benchmarking website, apparently running on a Sony smartphone. There has previously been speculation that Sony is in line to produce the next Nexus phone, which may lend some credence to this rumour.

Android 5.0 release date

Google has announced that its next developer conference - Google IO - will take place from May 15 to May 17 2013, a month earlier than 2012's June dates. Given that Google announced Android 4.1 Jelly Bean at 2012's IO conference, it's not unreasonable to expect to see Android 5.0 at this year's event.
Google IO 2012
Androids out in force at Google IO 2012

On 31 January, a Google IO showing of Android 5.0 looked more likely when screengrabs of a Qualcomm roadmap were leaked, showing Android 5.0 as breaking cover between April and June 2013.

Android 5.0 phones

Rumours of a new Nexus handset started trickling in during the third quarter of 2012, as we reported on 1 October 2012. There was speculation that this phone would be sporting Key Lime Pie, but sources who spoke to AndroidAndMe correctly claimed that the handset, which turned out to be the Google Nexus 4 would be running Android Jelly Bean.
While the Nexus 4 didn't appear with a helping of Key Lime Pie, speculation that we reported on 21 January 2013 suggests that the Motorola X Phone is the Android 5.0-toting handset that will be revealed at Google IO. According to a post on the DroidForums website, the phone will also feature a virtually bezel-free, edge-to-edge, 5-inch display.
The same leaked Qualcomm documents cited above also made mention of a two new Snapdragon devices, one of which will be, unsurprisingly, a new Nexus phone.
That Nexus phone is most likely the Google Nexus 5, though we'd be surprised to see it break cover at Google IO, given that the Nexus 4 only went on sale at the end of 2012.
On Monday 18 March, supposed images of the Nexus 5 surfaced, with the handset apparently being manufactured by LG. If the accompanying specs, leaked along with the photo by the anonymous source, are true, then the Nexus 5 will feature a 5.2-inch, 1920 x 1080 OLED display, 2.3GHz Qualcomm Snapdragon 800 processor and 3GB of RAM.

Samsung's Android 5.0 upgrades

Although Samsung is yet to officially confirm its Android 5.0 schedule, a SamMobile source is claiming to know which phones and tablets will be getting the Key Lime Pie upgrade. According to the source, the devices set to receive the upgrade are the Galaxy S4, Galaxy S3, Galaxy Note 2, Galaxy Note 8.0 and Galaxy Note 10.1.
Samsung Galaxy S4
As you'd expect, the S4 will be getting an Android 5.0 update

Android 5.0 features

For 24 hours, it seemed as though the first kinda, sorta confirmed feature for Android 5.0 was a Google Now widget, which briefly appeared in a screenshot on the company's support forum before being taken down. As it was so hurriedly pulled, many people assumed it was slated for the big five-o and accidentally revealed early.
As it happened, the following day, on 13 February 2013, the Google Now widget rolled out to Jelly Bean.
On 28 February 2013, we learned from Android Central that Google is working with the Linux 3.8 kernel, which gives rise to the notion that this kernel might make it into Android 5. One improvement that the 3.8 kernel brings is lowered RAM usage, which would mean a snappier phone with better multitasking.
While we wait on Key Lime Pie features to be revealed and scour the web for more Android 5.0 news, TechRadar writer Gary Cutlack has been thinking about what we want to see in Android 5.0 Key Lime Pie. Hopefully the new mobile OS will feature some of these things. . . .
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Tips for Backup and Restore in Linux . . . .

March 23, 2013 0
1. Before you backup your system, be specific of what type of data to backup, (Is it a Full or an Incremental or a Differential Backup?), where to backup (Flash drive, Hard-disk, Over Network) and what to Backup (just the home folder or the root itself).

2. To list all files in an archive file,
 
1# tar -tvf archive.tar
 
3. You need to verify that the backup made can be restored because once the data is removed, your backup cannot be restored, and then you can only be sorry.
To check if your backup process is working properly, use –compare (-d) option
 
1# tar --compare --verbose -f backup.tar.gz
 
4. If your backup needs more than one tape, you need to use the –multi-volume (-M ) option
 
1# tar  -cMF  /dev/fd0H1440  /home/rabi/
 
5. Incremental dumps depend crucially on time stamps, the results are unreliable if you modify a file’s time stamps during dumping (e.g., with the ‘–atime-preserve=replace’ option), or if you set the clock backwards.
 
6. Be sure of the order in which you are extracting incremental backup because GNU tar tries to restore the exact state of the file system when the archive was created. Therefore, it will delete those file that did not exist when the archive was created.
 
7. Backup over a Network
(a) Using Netcat
 
1# nc –l  1024 > backup.tar.gz
 
The choice of port is entirely up to the user, as long as it is 1024 or larger
 
- In Sending Computer, type
 
1# tar -cvpz <all those other options like above> / | nc -q 0 <receiving host> 1024
In  <receiving host> replace with the name of the computer on the network.
(b) Using SSH
 
1# tar -cvpz <all those other options like above> / | ssh <backuphost> "( cat > ssh_backup.tar.gz )"
ssh_backup.tar.gz Is the name of the file that will be created on the machine indicated.
<backuphost> – Should be replaced with the name of the computer in question on the network.
 
8. Restore over a Network
 
1# nc -l 1024 | tar -xvpjf - -C /mnt/disk
You need to mount the disk before executing this command.
 
Sending Computer
 
. . .# cat backup.tar.gz | nc -q 0  1024
 
 
 



 
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