Grid on the left:
Backlog - When registering an order or production, the quantity will appear her - live.
Shortage - a job runs every 5 minutes (this is calculated by the job)
Blocked -   a job runs every 5 minutes (this is calculated by the job)
Sup Backlog - When you register a supplier order the quantity will appear here - live.
Stockstatus - a job runs every 5 minutes (this is calculated by the job)

Grid on the right:
Free -  a Job runs every 5 minutes (this is calculated by the job) 
Stock - a job runs every 5 minutes (this is calculated by the job) 
Min.Stock - live (if you enter/change the Quantity in the field: reorder point on the article, it is updated here-live.
                           But the calculation of the 'shortage' will be by done by the job that runs every 5 minutes). 
in transit - When goods are in transfer, the quantity will show here for the chosen location - live. 
Open Supplier Orders - If you add a purchase order in status 1 (SPO/SOA), the quantity will appear here - live.
Supplier Backlog - When you register a purchase order (SPO/SOA) the quantity will appear here -  live.
Open Customer orders - When you add a customer order (COA) in status 1, the quantity will appear here - live.
Backlog - When you register a customer order (COA) or production work order (PWO) the quantity will  
                 appear here - live.
Consumed/shipped - When you register Shipping advice (CSA) the quantity will appear here - live.

Every 5 minutes a job runs that will calculate the inventory: 
Total stock quantity, free quantity, free quantity on supplier orders.
For the specific locations it calculates the stock quantity, free quantity, shortage, pending, when requested, minimum stock quantity, (re-order point), supplier request date, blocked quantity, and free quantity on a supplier order.  

All this information is shown in the PUR3 screen.