A Date storage area on the ground floor of Al Hazm fort.
The raised channels that can be seen in the image above were used for storing Hessian type sacks of dates. They were stacked one on top of the other and as the juice was forced out of the lower sacks, it ran through the channels into a catchment area.
This juice had a number of uses; a very nutritious food, medicinal qualities both internal as medicine & external in the form of salves, can be used as a sweetener like honey and I am sure in the case of Al Hazm Fort, a military use! Boiled and poured through the murder holes above entrances.
From that well-known on-line encyclopædia.
Dates have been a staple food of the Middle East and the Indus Valley for thousands of years. They are believed to have originated around Iraq, and have been cultivated since ancient times from Mesopotamia to prehistoric Egypt, possibly as early as 4000 BCE. The Ancient Egyptians used the fruits to make date wine, and ate them at harvest. There is archaeological evidence of date cultivation in eastern Arabia in 6000 BCE. (Alvarez-Mon 2006).
There is also archaeological evidence of date cultivation in Mehrgarh around 7000 BCE, a Neolithic civilization in what is now western Pakistan. Evidence of cultivation is continually found throughout later civilizations in the Indus Valley, including the Harappan period 2600 to 1900 BCE.
In later times, traders spread dates around South West Asia, northern Africa, and Spain. Dates were introduced into Mexico and California by the Spaniards in 1765, around Mission San Ignacio.
Fossil records show that the date palm has existed for at least 50 million years.