Chapter 1 - Quiz
Which of the following operating systems is not open source?
-- A) Windows B) BSD UNIX C) Linux D) PCLinuxOS
What is a bootstrap program, and where is it stored?
A bootstrap is the initial program that the computer runs when it is powered up or rebooted. It initializes all aspects of the system, from CPU registers to device controllers memory contents. Typically, it is stored in read-only memory (ROM) or electrically erasable programmable read-only memory (EEPROM), known by the general term firmware, within the computer hardware.
Explain why an operating system can be viewed as a resource allocator
A computer system has many resources that may be required to solve a problem: CPU time, memory space, file-storage space, I/O devices, and so on. The operating systems acts as the manager of these resources. Facing numerous and possibly conflicting requests for resources, the operating system must decide how to allocate them to specific programs and users so that it can operate the computer system efficiently and fairly
What role do device controllers and device drivers play in a computer system?
A general-purpose computer system consists of CPUs and multiple device controllers that are connected through a common bus. Each device controller is in charge of a specific type of device. The device controller is responsible for moving the data between the peripheral devices that it controls and its local buffer storage.
Describe why multi-core processing is more efficient than placing each processor on its own chip.
A large reason why it is more efficient is that communication between processors on the same chip is faster than processors on separate chips.
Explain the difference between singly, doubly, and circularly linked lists
A singly linked list is where each items points to its successor. A doubly linked list allows an item to point to its predecessor or successor. A circularly linked list is the where the last element points back to the first.
Which of the following statements is false?
A) Mobile devices must be concerned with power consumption. B) Mobile devices can provide features that are unavailable on desktop or laptop computers. -- C) The difference in storage capacity between a mobile device and laptop is shrinking. D) Mobile devices usually have fewer processing cores than a standard desktop computer.
Which of the following statements concerning open source operating systems is true?
A) Solaris is open source. -- B) Source code is freely available. C) They are always more secure than commercial, closed systems. D) All open source operating systems share the same set of goals.
Which statement concerning privileged instructions is considered false?
A) They may cause harm to the system. B) They can only be executed in kernel mode. -- C) They cannot be attempted from user mode. D) They are used to manage interrupts.
Explain the purpose of an interrupt vector
An interrupt vector is merely a table of pointers to specific interrupt-handling routines. Because there are a fixed number of interrupts, this table allows for more efficient handling of the interrupts than with a general-purpose, interrupt-processing routine.
Which two operating systems currently dominate mobile computing
Apple's IOS and Google's Android
Which of the following is proper of peer-to-peer systems?
Clients and servers are not distinguished from one another
Describe cloud computing
Cloud computing is a type of computing that delivers computing, storage and application services across a network. Cloud computing often uses virtualization to provide its functionality. There are many different types of cloud environments, as well as services offered. Cloud computing may be public, private, or a hybrid of the two. Additionally, cloud computing may offer applications, platforms, or system infrastructures.
Why are clustered systems considered to provide high-availability services?
Clustered systems are considered high-availability in that these types of systems have redundancies of taking over a specific process or task in the case of a failure.
Describe why direct memory access is considered an efficient mechanism for performing I/O
DMA is efficient for moving large amounts of data between I/O devices and main memory. It is considered efficient because it removes the CPU from being responsible for transferring data. DMA instructs the device controller to move data between the devices and main memory.
Which of the following would lead you to believe that a given system is an SMP-type system?
Each processor performs all tasks within the operating system
A dual-core system requires that each core has its own cache memory
False
All computer systems have some sort of user interaction
False
Solid state disks are considered volatile storage
False
UNIX does not allow users to escalate privileges to gain extra permissions for a restricted activity
False
The operating system kernel consists of all system and application programs in a computer
False Memory management, hardware, device drivers, filesystem drivers, network management, and others. Excluding application programs.
A system call is triggered by hardware
False Triggered by executing code
Computer systems can be divided into four approximate components. What are they?
Hardware, operating system, application programs, and users.
Explain cache coherency
In multiprocessor environments, two copes of the same data may reside in the local cache of each CPU. Whenever one CPU alters the data, the cache of the other CPU must receive an updated version of this data. Cache coherency involves ensuring that multiple caches store the most updated version of the stored data
Describe the operating system's two modes of operation
In order to ensure the proper execution of the operating system, most computer systems provide hardware support to distinguish between user mode and kernel mode. A mode bit is added to the hardware of the computer to indicate the current mode: kernel (0) or user (1) When the computer system is executing on behalf of a user application, the the system is user mode. However, when a user application requests a service from the operating system (via a system call) is must transition from user to kernel mode to fulfill the request.
In what way is an operating system like a government?
It creates an environment within which other programs can do useful work.
The most common secondary device is __
Magnetic disk
Why is main memory not suitable for permanent program storage or backup purposes?
Main memory is volatile memory in that any power loss to the system will result in erasure of he data stored within that memory
__ operating systems are designed primarily to maximize resource utilization.
Mainframe
__ is a set of software frameworks that provide additional services to application developers
Middleware
Distinguish mobile computing from traditional desktop computing
Mobile computing take place on handheld devices and tablets. Because these devices are portable and lightweight, they typically do not have the processing power and storage capacity of desktop systems. However, features such as GPS and accelerometers have allowed mobile devices to provide functionality that is unavailable to desktop systems.
Distinguish between uniform memory access (UMA) and non-uniform memory access (NUMA) systems.
On UMA systems, accessing RAM takes the same amount of time from any CPU. #same-time On NUMA systems, accessing some parts of memory may take longer than accessing other parts of memory, thus creating a performance penalty for certain memory access. #different-time
Describe the differences between physical, virtual and logical memory
Physical memory is the memory available for machines to execute operations (i.e. cache, random access memory, etc.) Virtual memory is a method through which programs can be executed that requires space larger than that available in physical memory by using disk memory as a backing store for main main memory. Logical memory is an abstraction of the computer's different types of memory that allows programmers and applications a simplified view of memory, and frees them from concern over memory-storage limitations
Explain the difference between protection and security
Protection is concerned with controlling the access of processes or users to the resources of the computer system. The role of security is to defend the system from internal or external attacks.
Distinguish between system and application programs
System programs are not part of the kernel but still are associated with the operating system. Application programs are not associated with the operating of the system.
Describe the computer-server and file-server types of server systems
The compute-server system provides an interface to which a client can send a request to perform an action (for example, read data from a database); in response, the server executes the action and sends back results to the client. #interface #client #request #action #response #server #executes #results The file-server system provides a file-system interface where clients can create, update, read, and delete files. #interface #CRUD An example of such system is a Web server that delivers files to clients running Web browsers.
Flash memory is slower than DRAM but needs no power to retain its contents
True
Interrupts may be triggered by either hardware or software
True
Processors for most mobile devices run at a slow speed than a processor in a desktop PC
True
Solid state disks are generally faster than magnetic disks
True
There is no universally accepted definition of an operating system
True
Virtually all modern operating systems provide support for SMP
True
What is the main disadvantage of storing information on a magnetic disk drive as opposed to main memory?
While disk drives can store more information permanently than main memory, disk drives are slower.
A __ is a customer build of the Linux operating system
distribution
A __ provides a file-system interface that allows clients to create and modify files
file-server system
A clustered system __
gathers together multiple CPUs to accomplish computational work
A __ is the unit of work in a system
process
Embedded computers typically run on a __ operating system.
real-time
Two important design issues for cache memory are __
size and replacement policy
What are some other terms for kernel mode?
supervisor mode / system mode / privileged mode
A __ can be used to prevent a user program from never returning control to the operating system
timer
The two separate modes of operating in a system are
user mode and kernel mode