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EECS678Exam1
Question | Answer |
---|---|
What is the user's view of the OS? | Makes it easier for the user to interact with the hardware. EX. read/write programs,resource management, etc. |
What is the system's view of the OS? | Manages resources, requests, and controls the hardware form a systems standpoint. |
Explain the OS goals. | -Efficiently use all resources available in a timely manner -Allow multiple tasks to be used at once -Ease of use and resource sharing -Convenience |
What is multiprogramming OS? | Multiple programs can run at once; allocates jobs in efficient manner to reduce down time [job scheduling] |
What is batch OS? | queues everything, runs them all at once, then prints at once |
What is timesharing OS? | multiple programs can be run at once with multiple users; users can interact with jobs at the same time |
How does an OS ensure protection between two user processes? | The address space of one process is separated from the address space of another process |
How does an OS ensure its own protection as well as that of the other system resources? | The kernel specifies the difference between user and root, only allowing certain changes. |
What is the level, access time, and size of the Registers in the storage hierarchy? | Level 1, > 1KB, 0.25-0.5 ns |
What is the level, access time, and size of the Cache in the storage hierarchy? | Level 2, > 16MB, 0.5-25 ns |
What is the level, access time, and size of the Disks in the storage hierarchy? | Solid State: Level 4, < 1TB, 25000-50000 ns Magnetic: Level 5, <10TB, 5000000 ns |
The architecture registers are managed by the hardware (T/F)? Explain. | False, it is managed by the compiler |
The user can directly manage the disk (T/F)? Explain. | False, it is managed by the OS |
Explain how the OS provides virtualization. | It runs under the control of a hypervisor. |
Name a few of the OS services to help the user. | - User Interface - program executer - I/O operations - file-system manipulation - inter-process communication - error detection |
Name a few OS services for efficient system operation. | - resource allocation - accounting of system resource usage - protection and security |
What are system calls? | Programming interface to the services provided by the OS. |
How do system calls differ from other function calls? | They are mostly accessed by programs via API rather than direct system call use. |
What is an API? | Application Program Interface - provides a simpler interface to the user, reduces coupling between kernel and application, increases portability. |
Would you prefer to use in a high-level program? API or system call? | API |
What is the policy and mechanism in the design process? | Policy: What type of system to design? Mechanism: based on the goals chosen for the system and user |
What is the policy and mechanism in the implementation process? | Policy: what was decided in design Mechanism: language chosen and the design of the code |
What are the characteristics, advantages, and disadvantages of Monolitic OS design? | Characteristic: monolithic Advantage: simple Disadvantages: poor separation between interfaces and levels of functionality, difficult to maintain and extend |
What are the characteristics, advantages, and disadvantages of Layered Architecture OS design? | Characteristic: OS division in to multiple layers, upper layers use functions and services provided by lower-level layers Ad: more modular and maintainable, achieves info hiding, simple debugging and verification Dis: interdependencies between layers |
What are the characteristics, advantages, and disadvantages of Microkernel OS design? | Char: moves as much functionality from the kernel into "user" space, communicate between user modules using message passing Ad: easier to extend & port to new architectures, more reliable & secure Dis: performance overhead |
What is virtualization? | Takes over control of the host hardware resources, creates illusion that a process has its own computer system |
What are the benefits of virtualization? | -Multiple OSs can share same hardware -Apps in diff VMs isolated from each other -testing cross-platform -consolidation of many low-resource use systems into fewer busier systems |
Define process. | A program in execution; an instance of a program |
How is a process different from a program? | Program: passive, only text Process: active, code, data, PC, heap, stack, etc. |
In what order (from Max to 0) are the components in the process address space? | stack, BLANK, heap, data, text |
Describe what a kernel must do to switch context between two processes |