ya, S1, S2, S3 and S4 are what they do in the military, from wikipedia:
S1 is the personnel and administration officer at brigade level and lower.
S2 is the principal staff officer for all matters concerning military intelligence (MI), counterintelligence, security operations, and military intelligence training at the brigade level and lower.
S3 (sometimes also known as "operations officer" or "opso") is the staff officer for matters concerning operations, plans, organization, and training at the brigade level and lower.
S4 is an officer who manages the battalion's logistical support, aided by the S4 section and specialized platoons (support, maintenance) organic to the headquarters and headquarters company (HHC).