Are Deleted Files Really Gone If They Are Overwritten By New Data

Is a Deleted File Actually Gone?

Abstract

When you delete a file, by accident or on purpose, is the information actually gone? Can yous get it back? If yous accidentally deleted your five-folio report for schoolhouse, you are hoping it is not gone. On the other hand, if y'all do not want someone to become their hands on the goofy and unflattering pictures you and your best friend took while staying up belatedly the other night, y'all probably promise it is gone for skillful! It might be nice to know for sure either manner. Attempt this project to find out.

Summary

Short (ii-5 days)

You should already be comfortable using a reckoner.

Requires a reckoner with a difficult-disk drive and an adult helper who is comfortable using the calculator.

Very Low (under $20)

No issues

Sandra Slutz, PhD, Science Buddies

Objective

Experiment to see what information technology takes to completely delete a figurer file.

Introduction

Y'all deleted the file—it is gone. Or is it? This is a question computer experts get asked ofttimes. Sometimes the question comes from frantic students who accidentally deleted a long, hard-to-write paper. Sometimes the question comes from police officers or lawyers working on a criminal case. Either mode, the person asking is desperate to know the answer.

In a criminal case, information technology is the job of a forensic computer analyst to find out the respond. The analyst uses sophisticated tools to advisedly and painstakingly look through a suspect's computer to recover bear witness from saved files—and even files the suspect thought they deleted. In this project, yous volition do a similar task. Y'all volition search for figurer files that may or may not have been deleted using several possible deletion techniques. Before you get started, you need to know a bit about how computers store information and what information technology ways to delete something. We will give you a basic explanation hither, but yous should check out the resources in the Bibliography section for a more than complete agreement.

When a file is saved to a figurer's hard-disk drive, the file is stored in multiple sections, called clusters, on the hard drive. The number of clusters that the file takes up depends on how much information is in the file. The more than information, the larger the file, and the more than space information technology takes on the difficult drive. The computer only saves a file to clusters of the hard drive that it thinks of equally "empty." Information technology also creates a record of where information technology stored the file in a large tabular array. The table tells the computer what files are stored where. In Figure 1 you can come across an illustration of a book report stored across several clusters of a hard drive with empty hard drive space on either side.

If you select a file and press the delete push button, the file will go in to a binder marked Trash if yous are using a Mac, or marked Recycle Bin if you are using a Windows estimator. Elimination the Trash/Recycle Bin (if you do not know how to exercise this, ask an adult who is comfy using computers or do an internet search on "how to empty my computer'southward Trash/Recycle Bin") tells the calculator to go rid of the tabular array entry that says what the file is called and where it is stored on the hard drive. It as well signals to the reckoner to call up of those hard bulldoze clusters as "empty" again, even though there is information sitting in them.

Once the computer thinks of the difficult drive clusters every bit "empty," it can shop other files in those spaces by writing over the information that was previously in them. Figure two shows an example of this; once the book report was deleted, the calculator could shop other files in the same space. Notice that not all of the clusters are written over. This is a thing of luck. If a smaller file similar the photograph in the example shown in Figure two is stored in the same space a larger file, like the book study, used to have up, several of the clusters side by side to it may not be overwritten.

Using data recovery tools that look at whether a hard drive cluster is truly empty or not, forensic computer analysts can sometimes call back all or parts of a file if it has not been written over. You volition attempt this yourself using free information recovery tools for this scientific discipline project.

Sometimes people deliberately write over a file to keep the information secret. This is called overwriting or file shredding, and there are tools to practise this besides (you volition investigate some of them during your project). Practice y'all recollect information technology is possible to recover these files?

With the help of an developed who knows how to use the estimator, and permission from the reckoner's owner, yous will compare how much effort it takes to notice saved, trashed, deleted, and shredded files. Which of these do yous think you lot will be able to detect? How long practise you think it volition accept you lot? Expert luck searching!

Terms and Concepts

Forensic computer analyst
Hard-disk drive
Difficult-deejay drive clusters
Deleting a file
Information recovery
Overwriting files
File shredding
Operating organization
File extension

Questions

What are a person'due south expectations when they say they have deleted a file?
How are files stored on a hard disk drive? What happens when yous delete a file by emptying the Trash/Recycle Bin on a Windows or Mac operating arrangement?
What does a file recovery tool do and how does information technology work?
Under what atmospheric condition could a file non exist recovered?

Bibliography

This website is a good place to await up computer terms like hard drive, delete, trash, and overwrite.

Christensson, Per. (n.d.) The Tech Terms Figurer Dictionary. Retrieved December ii, 2016.

More than data about storing, deleting, and recovering files can be found in these resources:

How To Geek Contributors. (2015, September 29). Why Deleted Files Tin Be Recovered, and How Yous Tin can Forestall It. Retrieved Dec two, 2016.
Powell, Oliver. (2015, May 6). What is Data Recovery and How It Is Helpful for Y'all?. Retrieved Dec ii, 2016.

For help creating graphs, endeavour this website:

National Center for Educational activity Statistics, (north.d.). Create a Graph. Retrieved June 25, 2020.

Materials and Equipment

Computer with a hard-disk bulldoze; you must accept the owner'south permission to make files, delete them, search the estimator, and install software. Note: A solid state drive volition non work for this projection. Solid country drives are a different technology and do not deal with deleting data in the aforementioned way.
Mac or Windows operating system; if y'all want to use a figurer with a Chrome operating arrangement, you volition have to adapt the experimental procedure yourself. Chrome operating system does not have a trash/recycle option.
Developed helper who is comfortable using the estimator
Lab notebook

Experimental Procedure

Choosing Your Tools

To do this project, you need to find the tools to exercise iii different things on the estimator: search for a file, overwrite a deleted file (sometimes called shredding a file), and recover a deleted file. Before starting, make sure you have the computer owner's permission to exercise all of these things on the figurer!

The computer'south operating organization should come up with search tools for finding files. Make sure you lot know how to utilise them to find a file on the computer's difficult drive and in the computer'due south Trash (Mac) or Recycle Bin (Windows).
1. If you do not know how to search for files, inquire an adult to teach y'all or search for instructions online. If y'all are searching for instructions, make certain to be specific well-nigh which operating organization you are using. For example: "how to search for a file in Windows 10" or "how to search for a file in Mac OS X."
2. Practice making and finding files on the computer.
If you practice not already have a file recovery tool on your figurer, you will need to find one, download it, and install it.
1. Like search tools, file recovery software is usually specific to your operating system. At that place are several complimentary programs for Mac and Windows; a simple online search for "costless file recovery programs for [your operating arrangement]" can requite you several options. Two options to get you started are Recuva for Windows and MiniTool Mac Information Recovery.
2. In one case y'all accept selected a tool, downloaded, and installed information technology, practice recovering some files. Outset by making and saving a few text files (text files have .txt extensions and can be made using word processor programs like Microsoft Word or simpler programs like Notepad), deleting them, elimination the computer's trash/recycle bin and and so recovering the files with the software.
Lastly y'all volition need to find, download, and install a file shredding program on the figurer. Search for a complimentary tool for your computer'southward operating arrangement online, or read this how-to article for Mac and effort Eraser for Windows.
1. Your adult helper volition be the ane shredding files. Make sure they are comfortable using the software.

Preparing the Files

An adult helper who is comfy with the computer needs to prepare the files for you. If you lot did it yourself, you lot would know where the files are and it would exist impossible to practice the remainder of the project. Have your adult helper follow the instructions in this PDF. If you are a student, exercise not open the PDF until after y'all are done collecting all your data.

Collecting Your Data

Once your adult helper has followed all the instructions in the Preparing the Files department and created the files on your computer, you are fix to collect your scientific discipline project data. Your goal is to search for each of the files listed in Tabular array 1 and rate how difficult it was to find each one.

Determine which file from Table ane yous are trying to discover.
Search the computer for the file. The file should have a .txt extension.
1. Outset look on the computer'southward difficult drive using the operating system'south search tool. If you find the file, note that in Table 1 and write "very piece of cake" in the File Recovery Difficulty Level column.
2. If you do not find the file in the difficult bulldoze, try searching the Trash/Recycling Bin. If yous find the file, note that in Table 1 and write "like shooting fish in a barrel" in the File Recovery Difficulty Level cavalcade.
3. If y'all cannot notice the file anywhere on the computer, try running the file recovery tool and searching for it among the recovered files. If you find the file, annotation that in Table 1 and write "medium" in the File Recovery Difficulty Level column.
4. If you however cannot find the file and are set to surrender looking, note that in Tabular array i and put "difficult" in the File Recovery Difficulty Level cavalcade.

If you lot do find the file, also record what the text was in the file.
Repeat steps one-4 for each of the 12 files. When you have equally many establish of the 12 files as y'all can, download and open the developed helper PDF.
1. For each file y'all found, check to encounter if the text in the file you constitute matches the text that was supposed to be in the file. If it does friction match, you can be sure y'all take found the right file. If it does not match, check with your developed helper—you may not have found the file!
2. If you found the wrong file, you lot will need to go back and go on trying to find the right one. Make sure to update your data table as needed.
3. Copy the file treatments (saved, trashed, deleted, or overwritten) for all 12 of the files from the adult helper PDF in to your data table.

Analyzing Your Data

Make a summary table of your data like Table 2.
1. Look at the information from merely the files in the "saved" file treatment group. Summate how many of the files yous found in that treatment. The minimum number should be 0 and the maximum number should exist three.
2. Convert the File Recovery Difficulty Levels in Tabular array 1 from words to numbers. So summate the Average Difficulty Level for the "saved" file handling group.
  1. Very piece of cake should be a difficulty level of 1.
  2. Like shooting fish in a barrel should be a difficulty level of 2.
  3. Medium should be a difficulty level of 3.
  4. Hard should be a difficulty level of four.
3. Repeat steps a-b for the other three file treatment groups: trashed, deleted, and overwritten.

Make a bar graph of the Number of Files Plant.
1. You tin exercise this past hand on graph paper, apply a spreadsheet program similar Excel, or utilise an online graph making tool like Create a Graph.
2. Label the y-axis Number of Files Found. Label the ten-axis File Treatment Group and brand certain each bar is clearly labeled equally data from the saved, deleted, trashed, or overwritten handling groups.
Make a similar bar graph of the Boilerplate Difficulty Level.

Making Your Conclusions

Now that all your data is summarized in forepart of y'all, look at it carefully and figure out what conclusions you tin make from your experiment.
What does your information tell yous near what actions are required to make a calculator file truly gone?
How much effort does information technology accept to detect a file on a figurer? How does trashing that file, deleting it by emptying the trash, or overwriting information technology change the amount of effort needed to read the text in the file?

Enquire an Proficient

Practise you lot have specific questions nigh your scientific discipline project? Our squad of volunteer scientists can assist. Our Experts won't do the work for you, simply they will make suggestions, offer guidance, and help y'all troubleshoot.

Variations

Effort deleting (putting in the Trash/Recycle Bin then emptying it) larger word document files with a lot of text and images. Make certain the files are several MB large. Then apply the figurer to create and save other files for i day, several days, or even several weeks. How like shooting fish in a barrel is information technology to recover the deleted files? How does changing the amount of figurer use between when the files were deleted and recovered modify whether or not the file tin can exist recovered and the quality of the data recovered from the file?
Have y'all ever heard someone say that a estimator's difficult drive is fragmented? Read up on hard drive fragmentation to figure out how saving and deleting files might change how fragmented a difficult drive is. Can you devise a examination to look at the relationship between saving and deleting files and disk fragmentation?

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General commendation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Slutz, Sandra. "Is a Deleted File Really Gone?" Science Buddies, xx Nov. 2020, https://www.sciencebuddies.org/science-fair-projects/projection-ideas/CompSci_p061/computer-science/is-a-deleted-file-really-gone. Accessed 23 Apr. 2022.

APA Fashion

Slutz, S. (2020, Nov 20). Is a Deleted File Really Gone? Retrieved from https://www.sciencebuddies.org/scientific discipline-fair-projects/project-ideas/CompSci_p061/reckoner-science/is-a-deleted-file-really-gone

Concluding edit date: 2020-11-twenty

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