Choose between "Store without compression", "Fastest", "Fast", "Normal", "Good" and "Best" methods. "Store" writes files to archive at maximum speed and without compression. For every following method compression ratio becomes higher and speed lower, when going from "Fastest" to "Best". This is the only option available for RAR and ZIP archives on the dialog page, other options are for RAR archives only.
Size of memory area to find and compress repeated patterns in processing data. Larger dictionary may improve the compression ratio for big files, especially when creating a solid archive. But larger dictionary also decreases the compression speed and increases memory requirements. Proposed dictionary size values depend on free memory amount. You will be able to select larger dictionary if more memory is available. RAR 4.x maximum dictionary size is 4 MB.
Add the recovery record, which may help "Repair" command to restore an archive in case of damage. Recovery record size is specified in percent of archive size. Larger recovery record allows to restore a larger damaged area, but increases the archive size and needs more time to create. Usually 3 - 10% of archive size is a reasonable choice.
It is possible to create an archive consisting of several files. Such archive is called multivolume and individual files composing this archive are known as volumes. Here you can specify a size of single volume in multivolume archive.
Ask for confirmation before creating every volume. It is safe to change media with already created volume, when such prompt is displayed. This option is ignored if volume size is not specified.
Define a number of recovery volumes for multivolume archive. When extracting an archive, each recovery volume (.rev extension) allows to reconstruct one missing usual volume file (.rar extension). Number of recovery volumes must be less than the total number of RAR volumes in the set for RAR 4.x and must not be larger than tenfold amount of RAR volumes for RAR 5.0 format. Values exceeding the threshold are adjusted automatically. This option is ignored if volume size is not specified. You need to place all available .rar and .rev volumes to same folder to allow reconstruction of missing .rar volumes. It is also possible to reconstruct missing volumes without extraction: just select one of .rev files in the file list and activate "Repair" command or tap on .rev file name.