Presented at
DEF CON 33 (2025),
Aug. 9, 2025, 5 p.m.
(45 minutes).
The Commodore 64 home computer, which sold at least 12.5 million units from 1982 to 1994, was widely used during a formative early decade in the subcultures of hacking, phreaking, piracy, and cybercrime. Like ancient insects trapped in amber, discovered and studied millions of years later, ephemera of hacker history has been fortuitously preserved in the file system structures of C64 floppy disks from the 1980s and 90s.
Enthusiasts and researchers have created byte-for-byte copies of disks in order to preserve games, applications, and demos of the time period. What is less obvious, however, is that users of the time tended to reuse disks, deleting old files to make space for new programs. This and other use patterns have resulted in interesting data being retained in unallocated sectors alongside the overtly-accessible programs and data. Often, this data can be recovered and includes logs of online sessions, hacker text files, and more.
In this talk, Dr. McGrew describes software and workflow he developed to perform forensic processing and full-text indexing of over 650,000 unique C64 floppy disk images from publicly-accessible online archives. He will also present interesting findings from searches and analysis that illustrate, for the modern audience, day-to-day hacker communications and tools of the past.
References:
- Guiness Book of World Records - Most Computer Sales - [link](https://www.guinnessworldrecords.com/world-records/72695-most-computer-sales)
- Jason Scott, Textfiles.com - [link](http://textfiles.com/)
- Wolfgang Moser, D64 (Electronic form of a physical 1541 disk), D64.TXT, Nov 7 2008, [link](https://ist.uwaterloo.ca/~schepers/formats/D64.TXT)
- Schepers, Forster, Disk File Layout (D64, D71, D81), DISK.TXT, Mar 11, 2004, [link](https://ist.uwaterloo.ca/~schepers/formats/DISK.TXT)
- Immers, Neufeld, Inside Commodore DOS, 1985
- The Cutting Room Floor - [link](https://tcrf.net)
Presenters:
-
Wesley McGrew
Dr. Wesley McGrew is a house music DJ that also directs research, development, and offensive cyber operations as Senior Cybersecurity Fellow for MartinFederal. He has presented on topics of penetration testing and malware analysis at DEF CON and Black Hat USA and teaches self-designed courses on software reverse engineering and assembly language programming. Wesley has a Ph.D. in Computer Science from Mississippi State University for his research in vulnerability analysis of SCADA HMI systems.
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