Blood counting machines aspirate a very small amount of the specimen through narrow tubing followed by an aperture and a laser flow cell. Laser eye sensors count the number of cells passing through the aperature, and can identify them; this is flow cytometry.
In computing, Extract, Transform and Load (ETL) refers to a process in database usage and especially in data warehousing that performs: Data extraction â extracts data from homogeneous or heterogeneous data sources.
Designing an ETL process with SSIS: two approaches to extracting and transforming data. On the Internet you find a lot of articles explaining the concepts like the data warehouse and ETL. There is also lots of information about products and tools such as SSIS.