rslt=${rslt:-"/tmp/sgpdd_survey_`date +%F@%R`_`uname -n`"}
# what to do (read or write)
-actions="write read"
+actions=${actions:-"write read"}
# total size per device (MBytes)
# NB bigger than device cache is good
size=${size:-8192}
# record size (KBytes)
-rszlo=1024
-rszhi=1024
+rszlo=${rszlo:-1024}
+rszhi=${rszhi:-1024}
# Concurrent regions per device
crglo=${crglo:-1}