McAfee VCLCDE-AA-DA Product Guide - Page 19

VirusScan® Command Line 5.20.0 Product Guide 3 Using the Command-Line Scanner Using memory caches Using memory caches When scanning a file for viruses and other potentially unwanted software, the scanner reads the file into computer memory in amounts determined by the operating system. Although changes are not normally necessary, you can improve the scanning speed by increasing the amount of memory that the scanner uses. This can be controlled by the following options: „ /OCRS „ /OCMAX „ /AFC Options /OCRS and /OCMAX are intended for use with offline or remote storage, such as Hierarchical Storage Management (HSM). The /AFC option can improve scanning performance in some cases. OCRS Typically the scanner reads only a few kilobytes of a file at a time, therefore a large number of reads might be required per file. The /OCRS option causes the scanner to use a larger internal "cache" for each file read instead. The size of reads for this cache is determined by a value in the range 0 through 4, as follows: /OCRS=0 - 128KB /OCRS=1 - 256KB /OCRS=2 - 512KB /OCRS=3 - 1MB /OCRS=4 - 2MB OCMAX The /OCMAX option changes the maximum size of the internal cache for file reads. By default, the scanner typically caches up to eight reads per file and uses a cache read size of 128KB - and therefore a maximum cache size of 1M, which is 128KB x 8). When setting the maximum size explicitly, you must specify the value of /OCMAX as a number of Megabytes. See the following examples for /OCRS and /OCMAX. „ Use 512KB read size. This implies a maximum cache size (OCMAX) of 4MB (8 x 512KB). SCAN C:\ /OCRS=2 „ Use 1MB read size. This implies a maximum cache size (OCMAX) of 8MB (8 x 1MB). SCAN C:\ /OCRS=3 „ Use a 1MB read size, but limit the cache size to 4MB. SCAN C:\ /OCRS=3 /OCMAX=4 „ Use a 2MB read size, but limit the cache size to 8MB. SCAN C:\ /OCRS=4 /OCMAX=8 AFC When scanning files, the scanner places the contents into computer memory (or file cache) before scanning them. This option allows you to vary the amount of cache that the scanner uses. 19