Oracle Database Discussions

Hi Experts:
Oracle document states as : SYSTIMESTAMP returns the system date, including fractional seconds and time zone, of the system on which the database resides. The return type is TIMESTAMP WITH TIME ZONE.
As I know there are two setting (hardware time and system time ) the linux server. If we do not set hardware time to UTC. or both hardware /system time set to local time.
My question, does oracle database systimestamp return different value in pl/SQL code?

I have a database in linux server there are some data column in tables. if Linux server time setting changes time by time, does database machine time set changes afftect data value during
inset/update data value with oracle systimestamp in database?

does database linux server (PC) time setting affect oracle systimestamp return value?

I know server(PC) affect some front program ( incluse SQLPLUS) return value of building system function
Any wrong?
Thanks explaining?
Jim