Synonyms: Binary code
This term is applied to the compiled instructions contained within an executable file. Binary code is not human-readable and can only be ‘understood’ by the computer’s processor when the program is run.
Source code, by contrast, is made up of the statements created by a programmer using a text editor. Source code is human-readable, for anyone who understands the conventions used by that programming language (‘C’, ‘C++’, etc.), but can not be executed by a computer’s processor until it has been compiled.
The term open relay is applied to an SMTP server that is set up to process e-mail from an unknown sender, even if it is not intended for a recipient within the organization. The open relay acts as a sort of ‘blind go-between’, routing all e-mail regardless of its source or destination.
Using tools that are easily available on the Internet, spammers are able to use open relays to deliver large volumes of spam while covering their tracks. Since the e-mail they send out is routed through the SMTP server of a legitimate organization, it looks like it has come from a legitimate source.
Open source software is software that is developed, maintained and distributed freely, based on open collaboration between programmers. As the name suggests, the source code for the operating system or application is published openly. Various Unix-based operating systems have been developed on the open source principle.
An operating system (sometimes abbreviated as OS) is the collection of programs that loads when a computer boots and subsequently manages the operation of all other functions on the computer. This includes access to the computer’s hardware, use of the computer’s processor, memory management, etc.
Examples of operating systems are MS-DOS, Windows® XP, Linux, NetWare®, etc.
Viruses are often classified according to the technique they use to infect. An overwriting virus, as the names suggests, completely replaces the code in the infected file with its own. Of course, the original program no longer runs, so the infection becomes obvious. For this reason, overwriting viruses have never been successful at spreading in the field.