Some colleagues told me that they had computer crashes and therefore lost the original data set they used in publications.  Given the high-speed of technological change, perhaps it would be good to have different types of data storage systems, or to share data sets with colleagues to store it at different, sometimes distant, places. 

Respected Prof. Kamal,

Thanks for taking lead to start the discussion.  Superb arguments, The cost of copping the data is very trivial, but the information is priceless. I fully agree with you.

@Marcel M. Lambrechts, well said, systems can crash at any moment, therefore, it is better to store data on other media. But, I think at some stage you need to delete old data or files. Thanks for your prompt reply. i appreciate it very much.

It is very difficult to advise on which data to delete. Firstly I will advise that you backup your data regularly because you never can tell when an old data would be needed. Secondly I will advise that if you have to permanently delete a data, let it be the data that you have analysed and turned into information, even at this, I will suggest you keep an archive of such data in an external source where they can be retrieved. Talk of son-father-grandfather archival system.

Usually I copy all my data to external storage device, like external hard drive. No matter is it private or business material. When ever I have deleted something because I thought I won't need it any more, I  regret it. 

But when I write the paper work, for example, and download some material from the internet, then I put it in special folder and after I finish with my work, I delete it.  

Very important issue is to be well organized when doing this. So you can always find what you are looking for.  If you do it, you can store everything. But keep it in your mind, CD - s, and flesh discs don't last forever. I recommend external hard disc with powerful performances. 

Cloud storage is not my "thing" yet, but many people are using it. 

Dear @Asmat. Your question has not universal answer. Just few tips fro me:

I put important documents (my student thesis, my papers, software I often use, etc) inside different folders. I make a new folder for each student whom I am as supervisor or adviser. My published work go to different folder according to the publishing year. Other downloads (Doc, PDF, clips, etc.) under folders with informative title. When a drive (D:, E:, ...) is getting full I check those folders quickly and erase unnecessary files. If you do these on a regular bases you can use your PC few years more. Finally, some of big data can be transferred to DVD, to make up more disc space.

P.S.: I use Disk Cleanup regularly (every week).

@Vyacheslav Lyashenko, I like your comments. Really it is an important issue. You have given a good direction i.e. to classify data.

@ Adelere Ezekiel Adeniran, Welcome to this discussion. I appreciate your experienced talk. Do you think backup and archive are two different terms?

@ Masa Radulovic, thanks for joining. I do agree that important data should be written on external hard disc. Do you never ever delete data?

Dear Mahmoud Omid ,

Well said, there is no universal answer. I am interested to know how others are dealing with this issue. Thanks for sharing your experience.

Dear Asmat

I have 4 detachable hard disks to store data. I would like to store it one of them depending upon the type of data. If the data is not of much current use or has become obsolete, then I would delete it as well.

I do not usually delete data. I am always afraid I might need them later. Except junk results from my analysis. Even sometimes, I do regret deleting them whenever I need to check the results again. I have three hard disks on my system (about 1 TB each). I work on one, do weekly backup on one and biannual backup on one.

@Debi,

Thanks for participating. I see. But what to do if there is terabytes of data?

@Yusuf Aina ,

Welcome. Thanks for contributing with a quality and professionally sound answer. I agree with you that we should avoid data deletion but some times it may be necessary , then how to decide that?

@ Asmat Ali. Thanks for your kind words. The difference between backup and archive is that data backups are for the rapid recovery of data that are still operational, while data archiving stores data that are no longer in day-to-day use but must still be retained.

Thank you for this important question. I made a mistake upon the advice of a friend & I hope that none of the colleagues at RG will fall into it.

My friend advised me to open another e-mail account in a famous site besides my original e-mail account there & to upload all the video files (which are bulky) to that e-mail by attachments to messages from "me" to "me"!! I did that and felt some relief. After transferring more than 1 gigabyte video files, the e-mail account became hard to open although the name & password were absolutely correct. Soon afterwards, the very same site told me that the account has been closed which meant that I lost all my data without me breaking any law or any regulation. So please all RG colleagues, BEWARE. You either transfer your data to DVD or CD or even to flash OR delete any data that could be accessed easily through the internet & you do not need it immediately.

@Adelere Ezekiel Adeniran,

Thanks for prompt and professional reply. I appreciate your participation.

@Fadia W Alazawi,

Welcome and thanks for joining. I see, you have made good arrangements. I appreciate your views.

@Dr. Nizar Matar,

Thanks for your kind words and contribution. I appreciate that you have shared experience. I agree with you and endorse your reply:

"All RG colleagues, BEWARE. You either transfer your data to DVD or CD or even to flash OR delete any data that could be accessed easily through the internet & you do not need it immediately".

There are some applications that clear up you computer from files which are a kind of garbage. The for the remaining files, it is good to made backups or store the files into another disk. There are also personal cloud disks, not very expensive. Of course from time to time you need to spend some time to delete files which you do not want. 

Respected Costas Drossos,

Thanks for contributing. I agree, we have to clear our systems from garbage files and data regularly.

Dear Asmat, I agree with many of above statements. Apart from above points, I always delete those file at regular intervals which are either corrupted/ infected and may be harmful to my devices

Dear @Asmat, I prefer to archive the data than deleting it. I, usually, go back and use these data for other purpose.

Dear Asmat:

When we have a lot of data i.e. terabytes (this is the case of our Global NOVAC network, http://www.novac-project.eu) which include today 68 permanent stations around 25 most active volcanoes in 18 countries of four continents, sending data to a central server and two mirror database servers, delete data is really not a problem. 

When we are interpreting these data for an active volcano, in our specific case (spectra of UV-Vis gases emmitted from volcanic fumaroles) we commonly delete data with more that 4 ppm-m of error (or 25%).

I think it depends on what kind of data one records. A simple lab experiment on an electric machine will produce minute quantities of data compared to what my friends in geology produce, e.g Gustavo's volcanic data. Filtering definitely reduces the data load, but one should really preserve as much as possible.

For me, DVD is probably the safest medium. A scratched CD cannot be fully recovered and one should be careful of flash, which, if you read them enough times can start losing bits and are generally not recoverable. A DVD stores the data inside the substrate and can be polished and recovered quite reliably when scratched, only takes a few minutes to write and is relatively inexpensive. (I find dual layer DVD's to be a bit slow)

I keep several backups of my work on hard drives and then at least a copy or two on DVD in different buildings. I've learned the hard way when I lost all my work for my master's thesis due to an unfortunate power surge and both the server and my computer' hard drives were lost, complete with my data.

I haven't tinkered with blue ray yet, but I suspect it may be slower than single layer DVD. Perhaps someone here has used both blue-ray and DVD and can tell us which is more time efficient.

It depends on the nature of data. Financial data usually should not be deleted. Data of students` grades in universities should not be deleted.

Delete data that have redudancy or duplicate data for sure. But for other i agree with Prof. Abedallah, its better to archieve it as the concept of data analytic, data that is garbage now can be treasure for a decade.

For tranfer to dvd it have limited time to store data and possibility of scratch as Prof. David said.

At some stage we all have to delete data even externally stored data. In this fast moving modern age some but not all data can become obsolete. I have a policy of deleting obsolete data every 3years. Three years is a very long time to decide whether or not data has become obsolete. However, Some data never become obsolete! Such data can only die when you die, for example date of births of you immediate family and date of marriage :))

Data storage is cheap. For active projects, I use a secure cloud storage solution like Dropbox, OneDrive, GDrive, etc. My school has a backup server that is not connected to the internet for retired projects. I have various backup drives at home and have materials backed up on DVDs, etc. If they need to be secure, I encrypt them and lock them in a drawer. 

Even I afriad of deleting datas.. So, I store them in DVD or fleah Drives..

Before 2 months I tried something new which is good option.. that is Google Drive..

We can use cloud storage, Google Drive, Sky Drive, Dropbox..

Data storage is cheap these days and occasional deletion of obsolete data once in a while is enough . The more important issue is backup!

We should always remember to keep a backup of all important files!. I learned this lesson in a hard way long ago!.

@Ratan Khuman, I agree with you, always delete those file at regular intervals which are either corrupted/ infected and may be harmful to the devices.

@Abedallah M Rababah, good strategy because sometimes, we need old data, and if it is deleted then no way to get it back.

@Gustavo Garzon, welcome and thanks for contributing. I endorse your technically sound statement with minor modification (I hope you would not mind it):

Send data to a central server and mirror database servers, delete data is really not a problem

@David Johnson, Thanks for joining. I really appreciate that you have narrated your own experience. Yes, unfortunately it happens as you mentioned. For organizational datasets, @Gustavo Garzon has given a complete and viable solution.

Respected Mahfuz Judeh, you are very right, it depends on the nature of data.

@Dony Saputra, Thanks for participating. Is redundancy really data duplication?

Dear Issam Sinjab, thanks for a superb reply. I support and endorse your arguments.

Some data never become obsolete! Such data can only die when you die, for example date of births of you immediate family and date of marriage. Perfect.

@Richard John Smith, thanks for contributing. Do you think cloud storage is secure enough?

@Dhara Chavda, Welcome. G drive is a good option. But do you think, it is 100% reliable?

@Behrouz Ahmadi-Nedushan, well said, We should always remember to keep a backup of all important files.

Don't delete your data, use, please, cloud technologies

@Sylantyev Sergiy,

Thanks for participating and giving a very good piece of advice. You are right, as cloud technologies are being used by many people.

First go for other options before deleting Data.... 

Dear Asmat, the culture of archiving data must be part of the organizational framework. I prefer backup data then deleting data only if it is redundant or not useful. However the problem of data storage is a key question in certain organizations. In my institution many data were and are not archived, i don't know if it is a policy of deleting all previous work or institution history, but there is no mean how to retrieve research contributions and results of past and either present colleagues. Many of my previous personal work 'softwares too' was deleted or transferred to others without backups. The question of technology storage media is essential too as it evolves rapidly. So for me the question of data deleting is very stressful I've lost many of my work due to my working place policy and organizational instability: example a system expert, a neural network, system, a first and a second order wavelet transform, a framework of an information system, an optimization system, a 3d system.. The problem is I must reconstruct all this if i need to use them, unless they are wasted .

Dear @Fairouz, I totally agree with you; it occurs many times that some needed data were deleted.

@Fairouz Bettayeb,

Thanks for contributing with a detailed reply. Well said, the culture of archiving data. You have mentioned correctly, the problem of data storage is a key question in certain organizations. Can you please share and elaborate why?

Dear Dr. Abedallah, I appreciate your attitude to encourage our fellows.  

Dear @Asmat, thank you for your kind words.

It is a good practice to regularly review and decide appropriate retention periods for different kinds of data, files, etc in the personal as well as organizational computers and remove/shift/delete all such files/data which are no longer needed. However, it depends on the importance and relevance of data/files, purpose, contiguous circumstances, organizational policy, legal & regulatory requirements, etc. Certain file/data need to be retained for longer in some cases than in others. How long one retains different categories of personal data is based on individual working needs. Information that does not need to be accessed regularly, but which still needs to be retained, should be safely archived or put offline or transferred to external storage devices. I personally do so quarterly and remove all such data/files/photos/videoclips from my computer's hard disk by transferring them to external storage device to prevent clogging and maintain speed.

Dear Asmat,  any organization or institution must keep traces of its functioning, it is its memory. An institution without traces of its different research projects and programs and its successful researchers' products is  meaningless. How could it be designed a strategic plan of its functioning , its philosophy and culture of management?   Missing its scientific data, looks like keeping hidden or secret the real beneficiaries of the researches. Missing its scientific data is a waste of the long term invested money in it. I think any institution must be aware of its data 'past and present', it is its memory , without memory there is no present and no future and no learning from errors.... etc...

@YOGESH CHANDRA TRIPATHI, thanks for contributing. You are right; it depends on the importance and relevance of data.

@Fairouz Bettayeb, I appreciate your active contribution. Well said, any institution must be aware of its data 'past and present.

I am a digital pack-rat and delete very little. My solution has been to subscribe to a cloud service. Solid-state storage devices are my next choice

@Kurtis D. Reitsma,

Welcome and thanks for joining. I really appreciate your smart reply.

@ Asmat Ali

I prefer to keep all data on my laptop or external hard disk. I think all data is important. For example some films or video clips it maybe seems useless but if i decide to work on video annotation or action recognition in video, it will be rough and good dataset for like application. In my opinion all data is valuable. data->inforamtion->knowldge-> wisdom. If we don't have data we will not get knowledge.

@Osama Hourani , thanks for contributing. Excellent remarks,

all data is valuable. data->inforamtion->knowldge-> wisdom. If we don't have data we will not get knowledge.

Respected Prof. Kamal

I really like this smart picture.

I avoid deleting data because you never know when you will need it? We should store it in the storage disc and free the space on laptop or PC. 

@ Jaya Vikas Kurhekar, thanks for contributing. I appreciate your views.

@ Asmat, Thank you for appreciating !!!

iCloud gives you the ability to manage your storage by controlling your iOS device backups and choosing which documents you want to keep in the cloud. You can also free up storage space by moving or deleting old email messages that you no longer need.

Dear Asmat, this is a valuable debate. I do not store data in personal computers, laptops or mobile phones. I do not use public email services, but used groups in the past (Yahoogroups; which are still active). I use some storage in pen drives or in cloud (Dropbox, private host services etc.). Deleting is something I do everyday. It requires selective attention when doing brokering in social networks (LinkedIn, ResearchGate etc.). It is resource and time consuming when working with social and intellectual capital, in [virtual] infrastructures as wikis, private projects or distance educational programs. I count on several institutions infrastructures and processes, including those which use robots (a good public example is Wikipedia). Thanks for the opportunity! Best regards.

The question of what to delete can be simple depending on how you manage your files.  The simple part is to delete the files are 'temporary in nature' and keep the ones that you might need someday.  I have developed a naming convention and filing system, my desktop has 2-1 Tbyte drives that are mirrored....just in case.  I also use a cloud service to keep my most recent files that I need to access from multiple locations.  What is alarming to me is that when a scientist retires, it is not uncommon for that persons life work to be discarded, what a shame.  Statistical methods and ability to analyze data is improving at light speed.  Sure the results are in the journals but the data is more valuable.  The medical field has developed a nonprofit organization to store data and make it available for others to use.  As academics the rule is publish or perish and many are not willing to share data....how can we overcome this?

In general, what to delete and what to keep depends on the time management and the filing system you have.

What effect will deleting the incorrect record have on the data reporting data system?