 Some command-line processors (like DR-DOS codice_5, Multiuser DOS codice_437/codice_438 (Terminal Message Process), JP Software 4DOS, 4OS2, 4NT, Take Command and Windows cmd.exe) support a type of pseudo-environment variables named "system information variables" (Novell / Caldera terminology) or "internal variables" (JP Software terminology), which can be used to retrieve various possibly dynamic, but read-only information about the running system in batch jobs.The returned values represent the status of the system in the moment these variables are queried; that is, reading them multiple times in a row may return different values even within the same command; querying them has no direct effect on the system.Since they are not stored in the environment, they are not listed by SET and do not exist for external programs to retrieve.