Penn Computing

Penn Computing

Computing Menu Computing A-Z
Computing Home Information Systems & Computing Penn


Thursday, July 31, 2014

  New Resources
Travel Tips for Data Security
Free Security/Privacy Training Resources
Two-step verification
Combating Malware
Phishing Archive
Cloud Computing and Data Outsourcing
Best Practices for Applications with Confidential University Data
  Security "Greatest Hits"
Managing Passwords
E-mail Harassment & Forgery
Hoaxes, frauds & scams
Wireless Networking
Encryption & digital signatures
  Best Practices
Secure desktop computing
Secure servers
Secure data deletion
Securing printers
Tips for safe computing
Computing policies
  More in-depth information for
Local support providers
System administrators
  Security initiatives
Critical host compliance
Authentication & authorization
Penn Security & Privacy Assessment (SPIA)
Security Liaisons (Restricted Access)
Secure Share
Secure Space
Vulnerability Scanner
  Related links
Electronic privacy
Worms, trojans, backdoors

One Step Ahead: Almanac Security Tips - 2014

In each issue, Penn's Journal of Record, The Almanac publishes helpful tips and hints for dealing with information security and privacy matters. This page is a collection of all those published thus far.
New! You can now receive new One-Step-Ahead Security and Privacy Tips automatically!
You can subscribe via Email or RSS.

Table of Contents (view all)

Heartbleed OpenSSL Vulnerability
Security and Privacy Tips for World Travelers
Filing Taxes Online This Year? Take Steps to Protect Your Information!
If your computer runs Windows XP, you must update it now!
Why Should You Report Security Incidents? And How Do You Report One?
Photo and Video Privacy Issues
The Password is Dead, Long Live the Password!
Data Privacy Month: NSA Surveillance Panel at the National Constitution Center
Protecting Your Finances During This Year’s Holiday Shopping Season
Beware of Phishing E-mails in the Wake of Typhoon Haiyan
No E-mail from Penn Will Ask For Your Username/Password or SSN
The Children's Online Privacy Protection Act: Does It Apply to Your Website?
October: National Cyber Security Awareness Month; Free Secure Disposal of Paper and Electronics
What Basic Rules Protect Student Information at Penn? (September 2013)
Protecting Privacy and Security on Penn + Box

Whats popular?

   www    mobile devices    keyloggers    social networking    email    privacy    SSNs    identity theft    passwords    security    software    wireless    documents        phishing    home computing    virus    hackers

Tagged with security , delete

Tuesday, April 17, 2007 - Almanac Vol. 53, No. 30

When is a PC file truly deleted?

So, you dragged that sensitive file to the Recycle Bin, emptied the bin, and now the file is gone forever, right? Not so fast. Like cats, deleted files seemingly have nine lives. When you delete a file, the operating system simply changes the first character of the filename and marks the space the file occupies as being free. The filename and data remain on the drive until overwritten and are easily retrievable using widely available recovery and forensic tools.

But wait, there’s more. For speed and efficiency, Windows creates temporary files for storing file data while the file is open, and these temporary files often remain even after deletion. Windows also uses page- and swapfiles to create "virtual memory" for faster operation, and deleted files can often remain in these as well. And what about copies on backup tapes, CDs, or other media?

Windows XP has a "Disk Cleanup" utility that can be accessed via the Start/Programs/Accessories/System Tools/Disk Cleanup menu sequence. For secure file deletion, security experts recommend using one or more disk-wiping or "shredding" utility programs that are available from many sources, some for free or minimal cost. These programs will overwrite the space occupied by a deleted file with 0’s, 1’s, or random data and can be set to make multiple passes. Opinion varies on how many passes are needed, but three is considered sufficient in most instances.

A more thorough, not overly technical discussion of file deletion can be found at


Information Systems and Computing
University of Pennsylvania
Comments & Questions

Penn Computing University of Pennsylvania
Information Systems and Computing, University of Pennsylvania