Operating Systems Quiz1
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Complete list of Terms and Definitions for Operating Systems Quiz1

Terms Definitions
fragmentation holes in memory
AutoPlay Windows2000/XP/Vista/7 setting, along with autorun.inf, enabling Windows to automatically detect media files and begin using them
condition variable thought of as queues.
browser program specifically designed to retrieve, interpret, and display Web pages
Review Swap on page 232. Continue.
Pure code cannot be shared. (T/F) False
multicast sending a message to multiple receivers, but not all
aging a technique of gradually increasing the priority of processes that wait in the system for a long time.
platter the individual circle in the disk
True or False: Page replacement algorithms can be evaluated using a reference string and then computing the number of page faults on it. True
BIOS Basic Input/Output System. The BIOS software is built into the PC, and is the first code run by a PC when powered on. The primary function of the BIOS is to load and start an operating system.
Should an instruction to modify entries in a device status table be privileged? Yes.
Aero is the graphical user interface and the default theme in most editions of Windows Vista and Windows 7, operating systems released by Microsoft.
Answer: D Multiple choice:What is a Desktop?a) The Top of the desk where the computer sitsb) A tool that keeps track of all the data on diskc) Where all of a computer's memory is storedd) The Virtual desk on which all of your other programs and utilities run
From the computer's point of view, which of the following is the OS designed? Hardware
foreground task task which receives processor time priority, usually the one with which the user is interacting/using
marshalling packing and unpacking of messages in client-server mechanisms
shortest-job-first -scheduling policy. When the CPU is available, it is assigned to the process that has the smallest next CPU burst.-selects the job that is closest to finishing.
page table maps virtual pages to physical frames
Paging is used in most operating systems? True
Deadlock A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set.
T/F: Most OS's ignore deadlocks and pretend that they do not occur. True
bootable disk disk that contains a functional operating system; can also be a floppy disk, USB thumb drive, or optical disk
administrative shares Administrator tool to give local admins access to hard drives and system root folders
ROM Read Only Memory. Normally used to store firmware.
Should an instruction to turn off interrupts be privileged? Yes.
Should the instruction to switch to kernel mode be privileged? Yes.
Cooperative Multitasking A method that depends on the application itself to be responsible for using and then freeing access to the processor.
DXDIAG What tool allows you to test DirectX functionality?
Source The actual code that defines how a piece of software works
Which of these is communication related? Create/delete connection send/recieve messages transfer info attach/detach remote devices
Memory state saves the state of the memory registers
channel processor in spooling, devices could now access data in memory using channel processors. They connect card, drums/disks, printers, etc to the main machine.
cylinder groups a collection of a relatively small number of cylinders. File allocation is done within a single cylinder group whenever possible
C-SCAN type of disk head scheduling. It moves the head in one direction until an edge of the disk is reached then reset to the opposite edge.
True or false: the user program deals with logical addresses and it never sees the real physical address. True
BIOS(basic input output system) Classically, software routines burned onto the system ROM of a PC. More commonly seen as any software that directly controls a particular piece of hardware. A set of programs encoded in read-only (ROM) on computers. These programs handle startup operations and low level control of hardware such as disk drives, the keyboard and the monitor
CHAP(Challenge Handshake Authentication Protocol) common remote access protocol; serving system challenges the remote client, usually by means of asking for a password
default gateway In a TCP/IP network, the nearest router to a particular host. This router's IP address is part of the necessary TCP/IP configuration for communicating with multiple networks using IP
Device Driver A program that determines how a computer will communicate with a peripheral device.
Your anti-virus software detects a boot sector virus. What is a valid option for removing the virus?A Sys the driveB Run Fdisk/MbrC Reload the operating system by using an unattended installationD Format the drive B Run Fdisk/Mbr
shell acts as an interface between OS and user
What is nonpreemptive scheduling? Under nonpreemptive scheduling, when the CPU is given to a process, it keeps it until it either terminates or switches to the waiting state.
Should a function to issue a trap instruction be privileged? No.
x86 is a phrase commonly used to refer to operating systems intended to run on the Intel processor
Windows Catalog With the Release of Windows XP Microsoft expanded the idea of the "Hardware Compatibility List" to include software as well as hardware compatible with Windows .. What is this List now referred as?
Absolute code can be generated for ___. compile time binding
multilevel feedback queues n priority levels, each priority level has its own round robin, own quantum, which decreases with higher priority. Processes are demoted a priority level if they're still executing when a quantum expires
logical address space the set of all logical addresses generated by a program
priority inversion when a low priority process delays a high priority process because of hoare semantics. EX: a low priority consumer does not allow a high priority producer to keep producing.
multiprocessor systems have two or more processors in close communication, sharing the computer bus and sometimes the clock, memory, and peripheral devices. Advantages: increased throughput, economy of scale(cheap for the benefits), increased reliability (one processor going down doesn't affect the system)
linked allocation files stored as a linked list of blocks. Directory entry is a pointer to the first and last file blocks
dynamic relocation process is moved to another part of memory, but it doesn't require the program to be edited since it keeps logical address rather than virtual or physical address
Explain dynamic loading. In dynamic loading, the routines are not loaded until they are called. This allows better memory space utilization because unused routines are never called. This is useful for large amounts of code and also no special OS support is required.
bootstrap loader segment of code in a system's BIOS that scans for an OS, looks specifically for a valid boot sector, and , when one is found, hands control over to the boot sector; then the bootstrap loader removes itself from memory
cylinder single track on all the platters in a hard drive
What three components must be installed and configured correctly in any peer-to-peer network?A ClientB ServerC NICD ProtocolE Resource sharing A ClientC NICD Protocol
Should a function to read the clock be privileged? No.
Should a function to set the value of the timer be privileged? Yes.
background job capability Lets you carry out jobs like printing whilst for example downloading music
b)System Control Panel(Through the Performance tab) Virtual memory is configured through which system tool?a)Taskbarb)System Control Panelc)Memory Managerd)Virtual Configuration
d)Permissions grouped together for easy assignment Standard Permissions are ______.a) The same as Special permissionsb)Only the Read, Write and Execute permissionsc)Permissions assigned to users but not to groupsd)Permissions grouped together for easy assignment
what is the "index" attribute for? this windows specific attribute enables Windows Indexing Service to create an index of the files to speed up the search function.
Monolithic OS the OS is just one big program. Each program thinks that its running on a single OS with a single CPU.
What is compaction? If memory is fragmented, then it can be shuffled around so that all the free memory is together in one large block.
What are the benefits of threads • User responsiveness• Resource sharing: economy• Speed• Utilizing hardware parallelism
defragmentation(DEFRAG) procedure in which all the files on a hard disk are rewritten in disk so that all parts of each file reside in contiguous clusters. The result is and improvement in disk speed during retrieval operations
Boot sequence: 5 steps 1. POST checks for any hardware faults.2. BIOS checks devices (video card, ect).3. BIOS searches for device to boot from.4. BIOS looks for Master Boot Record.5. Code in boot sector takes over.
Do we send by copy or reference when we fork? By copy.
What is priority scheduling? A priority is associated with each process. The processes with the highest priority run first. the SJF methodology is a kind of priority scheduling. They are always prone to starvation.
What is the dispatcher? The dispatcher is the module that gives control of the CPU to the process selected by the short term scheduler.
Why is the command interpreter generally separate from the kernel? It is subject to change.
What is a Pthread? Pthreads refers to the POSIX standard for defining an API for thread creation and synchronization.
Window's Backup Utility To backup the files on your disks in Windows, which Windows program can you use?
What did Windows 3.1 for Workgroups incorperate in this particular OS version? It incorperated workgroup networking support using the NETBEUI protocol.
What is the in memory directory-structure? This cache holds the directory information of recently accessed directories.
bps(bits per second) how fast data is moved from one place to another
What's a thread pool? You create a number of threads at startup and put them in the 'thread pool' where they sit and wait for work. When a server receives a request, it awakens a thread from this pool if one is available and passes it the request for service. When it's done, it goes back to the pool.
What are the two flavors of threads? User threads and kernel threads.
What's the main difficulty a programmer must overcome in writing an OS for a realtime environment? Scheduling must NOT permit response time to exceed the time constraint or things will crash.
What is response time? The time from submission of a user request until the /first/ response is produced.
How does Linux create threads? Linux has clone() for making threads, but it doesn't distinguish between a process or thread. (also, we use the word task). Clone flags determine whether file system info is shared, if the memory space is shared, if signal handlers or open files are shared. Fork creates a new copy, but clone just points to the data structures of the parent task, depending on the flags passed to clone.
What is turnaround time? The time from entering the ready queue to termination for a process, including everything it does.
Which of the follow is an advantage of a multi-processor system? Increased throughput economy of scale increased reliability
What is external fragmentation? this happens as a result of the first and best fit memory allocation strategies. As processes are loaded and removed, the free memory is broken into smaller pieces. External fragmentation exists when there is enough total memory to satisfy a request but the memory is not contiguous.
What components does each thread have for itself? program counter, register set, stack pointer, thread ID
How are the virtual memory options set in Windows 98?A Settings, Control Panel, Virtual Memory.B Settings, Control Panel, 386 Enhanced, Virtual Memory.C Settings, Control Panel, System, Performance, Virtual Memory.D Settings C Settings, Control Panel, System, Performance, Virtual Memory.
What's a signal? A signal is used in UNIX to notify a process that a particular event has occurred. A signal may be received either synchronously or asynchronously, depending on the source and reason. All signals follow the same pattern: 1) a signal is generated by an event 2) a generated signal is delivered to a process 3) Once delivered, the signal must be handled
What are the advantages and disadvantages of explicit buffering? The programmer has to worry about allocating memory and the size of messages to explicitly buffer, but on the other hand your buffer can't grow until it eats all your memory.
Describe how you could obtain a statistical profile of the amount of time spent by a program executing different sections of its code. could issue periodic timer interrupts and monitor what instructions or what sections of code are currently executing when the interrupts are delivered.
What advantage is there to having diferent time quantum sizes at different levels of a multilevel queueing system? Processes that need more frequent servicing, for instance, interactive processes such as editors, can be in a queue with a small time quantum. Processes with no need for frequent servicing can be in a queue with a larger quantum, requiring fewer context switches to complete the processing, and thus making more efficient use of the computer.
Describe first come first served scheduling. The process that arrives first gets served first and finished before the next process. This is easy, but waiting times can be very long.
Some early systems had a memory partition that was not modifiable by the user job or the os. What is the problem with this arrangement? Passwords and other privileged data would have to be stored or passed through unprotected memory, becoming accessible.
What happens in the kernel to context switch between kernel threads? Context switching between kernel threads typically requires saving the value of the CPU registers fromthe thread being switched out and restoring the CPU registers of the new thread being scheduled.
Characterize the CPU activity of a CPU bound process. A few long CPU bursts.
1) Start Menu2) System Tray (systray) The Taskbar contains 2 major items.. What are they?
What was special about the server based version of windows 2000? it was the first to include microsoft's standards-based directory service software, Active Directory.
What is the boot control block? Contains info needed by the system to book an OS from the volume. In UFS, it is called the boot block, in NTFS it is the partition boot sector.
What is the Non-blocking style of message passing - send buffers message, so receiver will pick it up later- receiver gets a message or an indication of no message
Which of the following are advantages of protected mode memory, when compared to real mode memory? (Choose 2)A Direct ram accessB 16-bit compatibilityC The OS controls application access to maintain stabilityD OS manages the C The OS controls application access to maintain stabilityD OS manages the memory resources
Why do some systems store the operating system in firmware while others store it on disk? Some small devices like video game systems and cell phones just have rom or some relative of rom and they have their OS on board because there's nowhere else to put it.
How are Priority and FCFS related? FCFS gives the highest priority to the job having been in existence the longest.
What are the benefits and disasvantages of synchronous (blocking) communication? It's good because it means that a process blocks until an answer is received, so it knows what information it needs and waits to get it. The disadvantage is that the process does have to wait.
What is the purpose of system programs? System programs are bundles of useful system calls so that users don't have to re-invent the wheel with common utility programs.
How new is Windows Server 2003? It is the newest available in the line of server edition operating systems from Microsoft.
How does the system handle a page fault Determine if the reference is invalid, if not and the page is just not in memory then get an empty frame and swap the page into it. Reset the tables and set the validation bit to v (valid) and then restart the instruction.
What are the three main thread libraries in use today? POSIX Pthreads (user or kernel level) , WIN32 (kernel level), and Java (since running on a JVM usually, uses a thread library available on the host)
Give an example of some threads. A word processor may have a thread for getting input from the user, another for spellchecking, and another for displaying graphics.
What equation describes the estimated length of the next CPU burst? The next CPU burst = (weight of recent transactions)(length of this cpu burst) + (1 - weight of recent transactions)(past history)
What is the main advantage of the layered approach to system design? It is easier to debug and modify.
Open Task Manager, Select the appropriate task, and click end task What can you do if a program is not responding to any commands and appears to be locked up?
True or false: the backing store does not need to provide direct access to the memory images it contains. False, it must so that swapping can occur.
A solution to the critical section problem must satisfy three criteria. What are they? 1) Mutual exclusion. (If a process is running in its critical section, nothing else can run in its own critical section) 2) Progress (If no process is executing in its critical section and some process wants to enter its critical section, then only those processes that need to enter the critical section next should contend for the role) 3)Bounded waiting (There exists a bound on the number of times other processe can ente their critical sections after a process has made a request to enter its critical section and before that request is granted.)
What are some things you can do to prevent starvation? A round robin queue doesn't permit starvation. Have an overflow queue so that things that have been in the ready queue over a certain amount of time go to the overflow and are processed immediately after the current job finishes.
How could a system be designed to allow a choice of operating system from which to boot? Consider a system that would like to run both Windows XP and three different distributions of Linux (e.g., RedHat, Debian, and Mandrake). Each operating system will be stored on disk. During system boot-up, a special program (which we will call the boot manager) will determine which operating system to boot into. This means that rather initially booting to an operating system, the boot manager will first run during systemstartup. It is this bootmanager that is responsible for determining which system to boot into. Typically boot managers must be stored at certain locations of the hard disk to be recognized during systemstartup. Bootmanagers often provide the userwith a selection of systems to boot into; boot managers are also typically designed to boot into a default operating system if no choice is selected by the user.
What is a modify or dirty bit? This is a bit used to identify if a page has been modified. This is used to ensure that only modified pages are written to disk. There is no need to rewrite a page to disk if it is already there. This reduces the overhead associated with the page replacement algorithms.
If main forks does three forks with nothing in between them, how many child processes are there? 8! The first fork creates a process, so there are two processes and they both fork, so then there's four processes and they all fork, making eight processes. Eight processes! Ah ah ah ah!
Compare fixed size and variable sized messages. If you have a fixed size, you can have an explicit buffer because you know how much you will need to hold. Variable size messages preclude explicit buffering because you don't know how much space you'll need.
How do CPU utilization and response time conflict? We are able to use the CPU more when we are not busy with context switching. A balance must be made between how often we context switch and how much time we spend actually doing process work.
What is the concept we usually use to solve the critical section problem? Locks. A lock is like a talking stick for processes to use their critical sections. There is only one talking stick and only the person holding it can execute in his critical section.