DOS Days

Frisk Software International

F-Prot

The company name, a combination of the founder's firstname and surname, Fridrik Skulason, is probably not one you would remember, but their product, F-PROT, was a staple anti-virus utility back in the DOS era. It was made popular largely because for non-commercial private use, it was completely free to use. The Rekjavik, Iceland-based company started around 1995 with F-PROT as their core product.


The FRISK Software International website back in 2005

F-PROT typically has 3 files that make up the virus definitions ("signatures"), which are:

  • SIGN.DEF - DOS and Windows virus search/disinfection data
  • SIGN2.DEF - Trojan, Java/scripting/BAT and other virus search data
  • MACRO.DEF - Word and Excel macro virus search/disinfection data

I don't have any details of F-PROT versions earlier than version 3.

F-PROT Professional for Windows was first launched in 1993 by FRISK Software International's OEM partners Data Fellows (now F-Secure) and Command Software Systems.

F-PROT version 3.09 was released in April 2001.

F-PROT version 3.16a was made available for download in December 2004, with the last virus definitions on this version dated 9th February 2005. For DOS and Windows these definitions could detect 56,443 viruses and 56,082 trojans. In addition, it could detect 8,418 viruses for Word/Excel, 6,463 script viruses, 3,377 BAT file viruses, and much more.

F-PROT version 3.16b was made available for download in March 2005.

Version 3.16c was released in June 2006. It supported scanning inside .ARJ, .CAB, .LZH, .ZIP, and .RAR archive files (v2.5 and older only)

Version 3.16f of F-PROT anti-virus software for DOS is a complete monitor, scanner and disinfectant. This version has the latest definitions up to 8th January 2009 with over 311,000 virus definitions stored. It definitely wins the 'numbers game' claiming it can detect over 434,376 DOS/Windows viruses and 158,607 trojans, 44,232 scripting language viruses, 8,755 Word/Excel macro viruses, 698 Java viruses, 5,246 BAT viruses, 3,334 IRC INI file viruses, 605 IS INF file viruses, 687 UNIX shell script viruses, 248 PHP viruses, 620 UNIX file viruses, and over 15,750 others through generic means.

  
  
  

It can scan within archives (ARJ / CAB / LZH / RAR / ZIP), many packed executables and emails. Running it today requires the use of the /OLD command-line argument to ignore the fact that all .DEF (virus definition) files are out of date.

The F-PROT program comprises the following tools:-

F-PROT.EXE is the scanner which can run either as a standalone DOS application or via command-line arguments.
F-FCHK.EXE can be used to check individual files for infection.

F-Prot in Modern Times

The F-Prot AntiVirus for Windows product is still around today! (2023), though since 2012 has been a part of the Cyren company after its acquisition by Commtouch. FRISK’s founder, Friðrik Skúlason, joined Commtouch as vice president of antivirus technologies. F-PROT was declared end of life on July 31st 2021, so is no longer being maintained as a separate product.