CMSC 421 - Exam 1 (Graded A+)

Operating System correct answers A program that acts as an intermediary between the user of a computer and the computer hardware -Execute user programs and make solving user problems easier -Make the computer system convenient to user -Use the computer hardware in an efficient manner Resource Allocator correct answers Manages Resources -Decides between conflicting requests Control Program correct answers Controls what programs run and when they run Atomic correct answers Not interruptible Protection correct answers Protecting the system from itself -Usually programs within the system -Controlling resources -Not allowing processes to interfere with other processes or the actual system Security correct answers Keeps safe from all outside sources -I/O devices -User login -Network adapters OS Bootup Process correct answers Bootstrap program is loaded at power-up or reboot -Typically stored in ROM or EPROM, known as firmware -Initializes all aspects of system -Loads kernel / starts execution Microkernel correct answers Kernel is small, delegates much of core system functionality to user-space daemons -Typically only the most core functionality is implemented in kernel space -Process and memory management, message passing -Benefits include that it is easier to extend/port a microkernel, more reliable/secure (less code is running in kernel mode) -Detriments include performance overhead of user space to kernel space communication -Examples: MINIX, Mach Monolithic correct answers Kernel is relatively large, contains much code -File systems, device drivers, etc. are all run with full kernel privileges -Hybrid/Layered systems are still largely monolithic designs -Examples: Linux, UNIX Microkernel System Structure correct answers Moves as much from the kernel into user space -Communication takes place between user modules using message passing