The main difference with UNIX is that instead of utilities handling files, they can handle any "task". More operating system code was moved out of the kernel and into user space, resulting in a much smaller kernel and the rise of the term microkernel. Unlike traditional systems, under Mach a process, or "task", can consist of a number of threads. While this is common in modern systems, Mach was the first system to define tasks and threads in this way. The kernel's job was reduced from essentially being the operating system to running the "utilities" and providing them access to the hardware.
tHe mAin DifferenCE WIth uniX IS thAT instEad Of uTilities HandLiNG FILEs, tHey caN haNdLe anY "tAsk". morE oPEraTing syStem CODe wAS moved out of thE kernEL and Into user sPAce, resUltiNg in A much SMallER kernel aNd the rIsE of the TErm micrOKERNel. unLike TradItIonAl sYsteMs, UndEr mach a Process, or "Task", CaN CoNsist of a numbeR Of thReADs. wHIlE tHis iS coMmon in modeRN syStems, mach waS ThE first sysTEM to dEFInE taSks And tHreADs In thiS way. thE keRNeL's joB waS reduCED froM essenTially BEing the opeRatIng systEm to ruNNinG THE "uTIlitIES" And proVidIng tHem access To tHe hardwARE.