System test is done on a fully integrated system and is done at developers site by the testers team.
Acceptance test is of two types : alpha and beta
alpha is done at developers site and by the persons within the software developing organization.
while beta is performed by end users and at users site, not at the developers site.
My question is if both system and alpha testing is performed at developers site and is performed by persons within the organization then what is difference between the two???