V9 vs xlsx engines

[anming]

proc import datafile="/folders/myfolders/storm_damage.csv"
dbms=csv out =storm_damage_import replace;
run;

proc contents data=storm_damage_import;
run;

This code displays a V9 engine.

libname xlstorm xlsx "/folders/myfolders/storm.xlsx";
run;

proc contents data=xlstorm.storm_summary;
run;

 this code displays an xlsx engine. What is the physical meaning and differences of these engines?

[SASKiwi]

V9 is the default SAS engine for reading and writing SAS datasets:

https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.5&docsetId=engsas7bdat&docsetTarget=...

This engine is capable of reading external data files, including CSV files.

The XLSX engine is used for reading and writing Excel workbooks in XLSX format, usually designated by the XLSX file extension:

https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.5&docsetId=acpcref&docsetTarget=n0oj...

There are many other engines available in SAS used for reading and writing external data files and databases.

[mkeintz]

You cannot open a V9 sas dataset with excel.

But a xlsx library identifies an excel file readable and writable with excel.  Yet SAS can also read/write to it, treating it as a "foreign" storage format.  SAS can read/write to a number of foreign formats (traditionally spss, osiris, more recently json, xml) implemented by corresponding engine options in a libname statement.