Quite often, the term "antivirus program" is used to refer to only one class of antivirus software, antivirus scanners. Scanners can identify thousands of known viruses. Many of modern scanners are equipped with heuristic analyzers that can detect -- with certain probability, sometimes relying on indirect evidence -- unknown viruses.

There are also other classes of antivirus software. Although simple and intuitive in use, scanners alone cannot secure your system against viral attacks. For more efficient and reliable protection, you will have to integrate different antivirus programs into a single suite. Why? Let's try to understand.

• Firstly, scanners are slow and this is the most obvious disadvantage that prevents their daily use. When scanning a file, a modern scanner has to emulate CPU commands in order to be able to detect polymorphic viruses -- and this is a time-consuming process. Scanning large disks may take several hours. Memory-resident scanners also adversely affect overall system performance.

• Secondly, you have to update scanners regularly. Only the latest version of a scanner -- with its databases that contain the signatures of recently detected viruses -- can provide an adequate protection. If not updated for a mere couple of weeks, a scanner is considered out-of-date.

Antivirus integrity checkers are free from these drawbacks. For instance, ADinf can complete disk scan in just a few minutes and doesn't require frequent updates. And it is still able to detect both known and unknown viruses.

However, integrity checkers alone cannot provide an absolute protection either, since they are not designed to check new files. The best approach is to use both a scanner and integrity checker. You'll still have to update the scanner's databases, but this won't be such a critical issue anymore since any unknown viruses will be reliably detected by the integrity checker.

ADinf supports interface to antivirus scanners, in particular, DrWeb, AVP and McAfee VirusScan. If a file was checked by a scanner and hasn't changed since, there's no point in checking it with the scanner again. So, ADinf can create a list of new, changed, renamed, and moved files, i.e. files that do require an antivirus check. Then it can launch a scanner and pass the list to it. This technique can help you considerably reduce overall scan time and organize real daily antivirus checks in your system. ADinf became a real user of your scanner.

You will find ADinf useful for other purposes, too. It can help you streamline the maintenance of your disks, find files that have been lost accidentally, analyze the results of system failures, check the integrity of your data (say, databases, archives, or documents), etc.