OS CLASSIFICATION

1.  We keep using so many OS's around in office,at home...some times windows...or a flavour of linux..UBUNTU..or the latest i touched upon was the upgraded BOSS..but was not aware that even OS have a classification.The classification is defined by Trusted Computer System Evaluation Criteria (TCSEC), a United States Government Department of Defense (DoD) standard that sets basic requirements for assessing the effectiveness of computer security controls built into a computer system. 

2.  TCSEC classifies any OS under 4 categories :

- D

- C

- B

- A 

3.  Few more things about the classication in point wise form :

- A has the highest security. 

- C, B and A are further classified as : C1, C2, B1, B2, B3 and A1.

- D defines Minimal protection

- C1 — Discretionary Security Protection

- C2 — Controlled Access Protection

- B1 — Labeled Security Protection

- B2 — Structured Protection

- B3 — Security Domains

- A1 — Verified Design

4. Thanks https://en.wikipedia.org