AVG is an umbrella term for a range of anti-virus and Internet security software for the Microsoft Windows, Linux, Mac OS X, and FreeBSD computing platforms, developed by AVG Technologies, a privately held Czech company formerly known as Grisoft.
Features
AVG features most of the common functions available in modern anti-virus and Internet security programs, including periodic scans, scans of sent and received emails (including adding footers to the emails indicating this), the ability to "repair" some virus-infected files, and a "virus vault" in which infected files are held (A quarantine area; also known as a "virus chest").
LinkScanner
The patent pending LinkScanner technology acquired from Exploit Prevention Labs and built into most AVG products, provides real-time protection against exploits and drive-by downloads. LinkScanner includes: Search-Shield – a safe search component that places safety ratings next to each link in Google, Yahoo! and MSN search results; plus Active Surf-Shield – a safe surf component that scans the contents of a web site in real-time to ensure it's safe being opened. A faulty upgrade in 8.0.233 causing users to lose internet access, as well as concerns regarding web analytics have made LinkScanner a controversial component (see "LinkScanner Concerns"). Concerns
Initial AVG Anti-Virus upgrades for version 8.0.233 contained a malfunction in the AVGNSX.exe process, blocking network activity and internet access. The AVGNSX.exe process is part of the LinkScanner utility. Current versions of avg are unaffected, as the product is at revision 9.0.xxx.
When AVG 8.0 was first released, its LinkScanner safe search feature was shown to cause an increase in traffic on web sites that appear high in search engine results pages. Since LinkScanner disguises the scans as coming from an Internet Explorer 6 browser when it prescans each site listed in the search results, web site usage logs showed incorrect and overinflated site visitor statistics. The prescanning of every link in search results also caused web sites to transfer more data than usual, resulting in higher bandwidth usage for web site operators and slow performance for users. AVG initially said site administrators would be able to filter the LinkScanner traffic out of their site statistics, leaving the problem of excess bandwidth usage still to be solved. Pay-per-click advertising was not affected by the increase in traffic.
In response to complaints, AVG announced that as of July 9, 2008 "Search-Shield will no longer scan each search result online for new exploits, which was causing the spikes that webmasters addressed with us", releasing a new build on that date that applies a local blacklist, then prefetches and scans only those links clicked on by the user.
Resource requirements
AVG had been known for its conservative resource requirements during its version 6.0 run. The AVG Anti-Virus Professional Edition required 16 MB of RAM and 20 MB of space on the hard drive.
Version 7.5 of AVG Free requires a Pentium (or compatible) CPU with 300 MHz and between 64–256 MB of RAM, depending on operating system (at least 64 MB with Windows 9x, at least 128 MB with Windows 2000 or newer, with more RAM recommended).
An additional caveat with version 7.5 in Windows XP, which is a multi-user system that allows more than one user to be logged in at a time, is that scheduled scans ran as separate processes, which created a situation in which there were two scheduled scans, one in each active account, running simultaneously and causing heavy hard disk throttling and considerable system lag. This fault was finally fixed in version 8.0 of the program.
Currently, both AVG Anti-Virus and AVG Internet Security require at least 256 MB of RAM for the computer as a minimum. The comparatively high use of paged physical RAM has led to crashes with some software, such as the Half-Life 2 series
