Hello Proud , Thanks for your reply.
That was just a guess ! It seemed to me from your answers.

Ok I will have a look at UnionFS to see its working.
Thanks for the link and idea, I will try my best to have such a system, I could keep all the basic required binaries on my secured partition and then use them to bootstrap the system.
My system would be able to restore system from like accidental deletion of files, broken upgrades (the system will be for ubuntu linux initially), wrong editing to conffiles, wrong changes to files like fstab. The need to restore would be specified by the user himself. If the user feels that the system is wrong he can restore it to a last known working state.
Ok. I understand the problem with my system, it would have user to do much , I could have it create restore points on everyday basis so that the backup is current for a day atleast. But ofcourse there is a dedicated single location of backup which might not save the system in situations of major crashes. I would need to work upon that, may be I provide an option to export the backups to a portable drive.
Yes , i am intending to work on a package state saving tool, which could save state of the installed packages and then restore them when needed. yes that's true, but this system would be useful in cases of small failures, I need to think of more ways to make it robust to severe damages.ce.

I am a computer engineering student I am working for open source so it could be just released in open source to benefit simple end users.

just out of curiosity, what language are you programming in?

grvsaxena, I'm in India too, and interested in things like this. Where are you??!!

Consider how your system will work if the user has made a typo in fstab and then rebooted, such that / or /abc are no longer correctly mounted. Or if they have broken a file or permission in key locations such as /boot, /bin, /lib, /usr/sbin, /usr/bin or /usr/lib.
I'm not sure you would build a reliable restore system by running it within the unstable OS it is restoring. I think only the snapshotting/restore point creation/trigger system could live there, and is then still as vulnerable to software and hardware issues as the OS it protects.

As for backups every day, would your system need all other processes to stop, i.e. be run right before shutdown or right after booting? If you plan to create restore points of a live system, how will you handle integrity issues such that many applications may require all files to be snapshotted at a single instance in time, while in reality a recursive per-file diff takes time and could well version some files before an app makes a change, and some after, such that restoring the mismatched pair could be an invalid state for the app and useless? A simple case would be you catch one copy of a file in one location before a move, then another copy of it after a move, but at any one time there was (and should be) only one copy of the file. It could be an app-specific backup/archive, a lock file, logfiles, there are many such examples.
You may also need to consider data not yet flushed to disk.
Ideally I think you want atomic snapshots for useful versions/restore points, without filesystem/kernel support I'm not sure how you achieve this.

Late edit:
I was not directly addressing how you would popularise your creation but rather what rivals surely already exist in the marketplace for the whole range of users from single installs to enterprises. A quick google for 'linux system restore' reveals many as well as discussions here at LQ from years ago. A key assumption in your mind seems to be that Windows system restore works well enough in the first place that replicating it to Linux is of benefit, and that the same conditions which make it useful there also carry over. Again, modern Linux tends to have robust package management with built in dependancy and repair mechanisms, this and the use of tested official package repositories allows for far more stable systems than Windows and the risk of 3rd party driver installs & downloaded utilities.

Hello Nbomr,
I will have a look at SElinux so that I could get such functionality.
Thank you very much.

Hello resetreset,
I am making changes in linux kernel, its written mostly in C and some assembly language(low level). I am in NIT, Jaipur.

Hello Proud,
Yes, you are right my system would not work in that situations, it will fail. I think I could have a system that could initiate a recovery using bootstrap which could be called using grub or initramfs. I will surely try that or have an option for using program using live cd.
My approach for the backup and restore is to save the packages of the system, and related files like dpkg-status, source.list, pakage-selection and then restore the package selection and all the files.
I am using dpkg-repack for packing up a package files and creating deb packages for them, this doesn't need to take backup right before shutdown. Yes my approach would definitely suffer from this issue. I think I could like pause a process using kernel support and then create a package for it and then resume it, maybe I could do that. Yes that's really a difficult thing to solve I suppose because I had not thought about such issues, actually I had not imagined about such issues. I am agree with you about the need of support of filesystem/kernel for the atomic snapshot thing. Actually what problem I thought about snapshot thing is that its too much complex for users to handle. But I think it maybe a better thing to design such a robust and reliable system instead of my approach.
Yes I agree with you , and also I think that a system for just saving the package state and then restoring it is not worth the effort.

hey that's great, I'm not a C guy, but I *do* love asm! we should become friends can I send you a PM?

Hey , sure that's a nice idea really, I have sent you a friend request but i don't have much idea of this forum quite new.

grvsaxena, did you send me an EMAIL by any chance? the email addr that LQ has is not what I use - I lost the password to that ages ago. i'm sending you a *PM*, read it



oh sorry I can't - have you turned that off? ok, sending you an EMAIL then - pleas read.