calculate the string width for numerical volume display and time display in
tree9f2242b52821914be22e7afcaf2fb8c9decf4ccd
drwxr-xr-x - CVSROOT
drwxr-xr-x - apps
drwxr-xr-x - firmware
drwxr-xr-x - gdb
drwxr-xr-x - tools
drwxr-xr-x - uisimulator
drwxr-xr-x - www