general purpose system, multi-user friendly

"open system" approach, safety leekages

timesharing, multi-tasking

no real-time ability

hierarchic file system

no warning or reconfirmation of dangerous commands

linkage of scripts and programs possible

no feedback about success of operation
(approach : "no news is good news")

high portability, kernel written in C (90%)

awful naming convention for commands
("small is beautiful" translating into "salvation through suffering")