• the system library abstracts the operating system from the ISIP environment, provides multi-lingual character encoding, and error handling

• Integral define some low level system functions to be used by other classes, like getEnv, getPid, etc.

• the Console class controls message which programmers might want to send to stdout

• MemoryManager can increase memory efficiency when we need to allocate a large number of identically sized objects, such as a linked list

• an Error class is used for error handling. everything in this class is static, so there is only one way to handle errors per program.