User programs interact with the kernel through a set of standard(71). They request services to be provided by the kernel. Such services would include accessing a file: open close, read, write, link, or execute a file; starting or(72)accounting records; changing ownership of a file or(73); changing to a new directory; creating,(74), or killing a process; enabling access to hardware devices; and setting limits on system resources. Unix is a multi -user, multi -tasking operating system. You can have many users logged into a system simultaneously, each running many programs. It's the kernel's job to keep each process and user separate and to regulate access to(75), including cpu, memory, disk and other L/O devices.

A．system commands

B．system transfer

C．system calls

D．system rings

[单选题]The user must interact with the (74) in order to accomplish task．A．PrinterB．memoryC．CPUD．operation system

[单选题] The user must interact with the (74) in order to accomplish task.(74)A． printerB． memoryC． CPUD． operating system

[单选题]The user must interact with the(73) in order to accomplish task.A．printerB．memoryC．CPUD．operating system

[单选题]（68） are those programs that help find the information you are trying to locate onthe WWW.（68）A． WindowsB． Search EnginesC． Web SitesD． Web Pages

[单选题]In(75)programming, the user determines the sequence of instructions to be executed, not the programmer.A．top-downB．structureC．data-drivenD．event-driven

[单选题]In(71)programming, the user determines the sequence of instructions to be executed, not programmer。A．structureB．event-drivenC．top-downD．data-driven

[名词解释] 内核（kernel）

[单选题]The kernel is the(66)of an operating system such as Windows98, Windows NT, Mac OS or Unix. The kernel provides basic services for the other parts of the operating system,(67)it possible for it to run several programs at once(multitasking), read and w

[单选题]C．CTV programs are _____ by satellite to the remotest areas in the country.[A] transferred[B] transported[C] transformed[D] transmitted

[单选题]Don’t turn off the computer before closing all programs_______you could hav