Prior to RedHatRHEL 7, their distributions were built on SysV, a manager that looks much like the legacy SystemVSystem V (init.dinit.d, rcrc, runlevels...).
They changed it to SystemDsystemd from RedHatRHEL 7.
But what is the real difference between SysV and the unixUnix-like SystemVSystem V?
Why did they call it SysV, if it's the same?