CS201 - Midterm

Compaction should always be performed only when there are jobs waiting to get in. True False

False

Database locking should be done only at the level of the entire database True False

False

is where the data and instructions of a computer must reside to be processed. a. Main memory b. Read-only memory c. I/O memory d. CPU

Main memory

1. Fill in the missing event that causes deadlock in a database. There are two processes (P1 and P2), each of which needs to update two records (R1 and R2) and the following sequence leads to a deadlock: 1. P1 accesses R1 and locks it. 2. P2 accesses R2 and locks it. 3. ____ 4. P2 requests R1, which is locked by P1. a. P2 releases R2. b. P1 requests R1 again. c. P2 releases R1. d. P1 requests R2, which is locked by P2.

P1 requests R2, which is locked by P2.

1. ____ peruse data packets as they pass by, examine each one for specific information, and log copies of interesting packets for more detailed examination. a. Packet filters b. Packet sniffers c. Spoofers d. Proxy servers

Packet sniffers

1. ____ is a form of social engineering whereby an intruder pretends to be a legitimate entity and contacts unwary users asking them to reconfirm their personal and/or financial information. a. Phishing b. Acting c. Impersonating d. Spoofing

Phishing

1. A ____ chip holds software that is used to start the computer. a. ROM b. CPU c. buffer d. RAM

ROM

1. The transition from ____ can be initiated by the Process Scheduler or the Job Scheduler. a. HOLD to READY b. RUNNING to FINISHED c. RUNNING to WAITING d. WAITING to READY

RUNNING to FINISHED

1. ____ systems are used in time-critical environments where reliability is key and data must be processed within a strict time limit. a. Hybrid b. Interactive c. Real-time d. Embedded

Real-time

is a way to optimize search times on hard disk drives by ordering the requests once the read/write heads have been positioned. a. SSTF b. LOOK and SCAN c. C-SCAN d. Rotational ordering

Rotational ordering

1. A file extension is usually two to four characters in length and is separated from the relative name by a period. True False

True

1. A processor is also known as a CPU. True False

True

1. An important function of the Processor Manager is to keep track of the status of each job, process, and thread. True False

True

1. Any vulnerability at the operating system level opens the entire system to attack. (T/F)

True

1. Associative memory is a name given to several hardware registers that are allocated to each active job whose task is to associate segment and page numbers belonging to the job being processed with their main memory addresses. True False

True

1. Deadlock is a system-wide tangle of resource requests that begins when two or more jobs are put on hold, each waiting for a vital resource to become available. True False

True

1. Demand paging introduced the concept of loading only a part of the program into memory for processing True False

True

1. Directories are special files that contain listings of filenames and their attributes. True False

True

1. First-come, first-served (FCFS) is the simplest device-scheduling algorithm; it is easy to program and essentially fair to users. True False

True

1. In a paged memory allocation scheme, to find the actual position of an instruction in memory, first the page number and displacement are determined. Then the operating system refers to the job's PMT to correlate the page with its page frame. True False

True

1. Once starvation has been detected, an algorithm can be implemented in which the system blocks new jobs until the starving jobs have been satisfied. True False

True

1. Research continues to focus on finding the optimum allocation scheme. True False

True

1. Resource holding, where a job holds on to one resource while waiting for another one that's not yet available, can be sidestepped by forcing each job to request, at creation time, every resource it will need to run to completion. True False

True

1. Shortest job next (SJN) is a nonpreemptive scheduling algorithm (also known as shortest job first, or SJF) that handles jobs based on the length of their CPU cycle time. True False

True

1. Single-user systems in a non-networked environment allocate, to each user, access to all available main memory for each job, and jobs are processed sequentially, one after the other. True False

True

1. The Device Manager is responsible for connecting with every device that's available on the system and for choosing the most efficient way to allocate them. True False

True

1. The buffers used in the 1950s to reduce the discrepancy in speed between the I/O and the CPU were conceptually similar to those now used routinely by Web browsers to make video and audio playback smoother. True False

True

1. The first attempt to allow for multiprogramming used fixed partitions. True False

True

1. The universal serial bus (USB) controller acts as an interface between the operating system, device drivers, applications, and the devices that are attached via the USB host. True False

True

1. There are many more sectors on an optical disc than on a magnetic disk of the same area. True False

True

1. With demand paging, three additional fields are introduced for each page in each PMT: one to determine if the page being requested is already in memory, a second to determine if the page contents have been modified while in memory, and a third to determine if the page has been referenced most recently. True False

True

Context switching is required by all preemptive algorithms True False

True

Networking was not always an integral part of operating systems True False

True

The Device Manager is responsible for connecting with every device that's available on the system and for choosing the most efficient way to allocate them. True False

True

There are two primary types of user interfaces: the graphical user interface and the command line interface. True False

True

1. Fill in the missing event that causes livelock. At an insurance company, the system performs many daily transactions. One day, the following series of events ties up the system: 1. Process P1 wishes to show a payment, so it issues a command to read the balance, which is stored in cylinder 20 of a disk pack. 2. ____ 3. P2 gains control of the I/O channel and issues a command to write someone else's payment to a record stored in cylinder 310. If the command is not "locked out," P2 will be put on hold while the control unit moves the arm to cylinder 310. 4. Because P2 is "on hold," the channel is free to be captured again by P1, which reconfirms its command to "read from cylinder 20." 5. Since the last command from P2 had forced the arm mechanism to cylinder 310, the disk control unit begins to reposition the arm to cylinder 20 to satisfy P1. The I/O channel would be released because P1 is once again put on hold, so it could be captured by P2, which issues a WRITE command only to discover that the arm mechanism needs to be repositioned. a. P1 is unable to find the information it needs, so requests a different READ operation for a different cylinder. b. P2 is put on hold while the control unit moves the arm to satisfy P1's request c. P1 discovers that another process has locked the portion of the disk it needs to access. d. While the control unit is moving the arm to cylinder 20, P1 is put on hold and the I/O channel is free to process the next I/O request.

While the control unit is moving the arm to cylinder 20, P1 is put on hold and the I/O channel is free to process the next I/O request.

1. A file's ____ filename includes all path information for that file. a. extended b. long-form c. absolute d. relative

absolute

1. A(n) ____ contains a list of files, each of which is associated with the names of users who are allowed to access it and the type of access each user is permitted. a. access control list b. capability list c. capability matrix d. access control matrix

access control list

The fixed partition scheme works well when a. jobs have different sizes b. all jobs are under 100K c. job sizes are not known in advance d. all jobs are of similar size

all jobs are of similar size

1. A variation of the LRU page replacement algorithm known as the ____ replacement policy is implemented with a circular queue. a. performance page b. bit shifting c. clock page d. round robin

clock page

1. What strategy contributes most to system recovery? a. encryption b. data replication c. integrity checking d. authentication

data replication

1. The number of characters that can be recorded per inch on a magnetic tape is determined by the ____ of the tape. a. parity b. length c. width d. density

density

1. Each peripheral device has its own software, called a(n) ____, which contains the detailed instructions required to start that device, allocate it to a job, use the device correctly, and deallocate it when it's appropriate. a. device driver b. device handler c. device software d. device controller

device driver

1. With ____ operating systems, users can think they are working with a system using one processor, when in fact they are connected to a cluster of many processors working closely together. a. embedded b. paged c. distributed d. buffered

distributed

1. The ____ method keeps the free/busy lists organized by memory locations, from low-order memory to high-order memory. a. first-fit memory allocation b. fixed partition allocation c. best-fit memory allocation d. dynamic fit memory allocation

first-fit memory allocation

1. Many computer users and some operating systems call subdirectories ____. a. databases b. volumes c. files d. folders

folders

1. When reading an instruction, the operating system can tell the ____ of each group of digits by its location in the line and the operation code. a. value b. assignment c. function d. order

function

1. The scheme of ____ removes the possibility of a circular wait and therefore guarantees the removal of deadlocks. a. saving and restoring job state b. hierarchical ordering c. preemption d. requesting all resources before job run

hierarchical ordering

1. The USB controller assigns bandwidth to each device depending on its priority. The ____ priority is assigned to real-time exchanges where no interruption in the data flow is allowed, such as video or sound data. a. standard b. highest c. medium d. lowest

highest

The phenomenon of less-than-complete use of memory space in a fixed partition is called a. internal fragmentation b. dynamic fragmentation c. fixed fragmentation d. external fragmentation

internal fragmentation

1. The most common mechanism for implementing multiprogramming was the introduction of the ____ concept, whereby the CPU was notified of events needing operating systems services. a. messaging b. paging c. sharing d. interrupt

interrupt

1. When data is stored in fixed length fields, data that extends beyond the fixed size ____. a. is broken up and stored in more than one field b. generates an operating system error c. is truncated d. combines multiple fields to accommodate the data

is truncated

1. One major disadvantage of encryption is that ____. a. it is inconvenient for users b. it is often ineffective c. it increases the system's overhead d. it is prohibitive in cost

it increases the system's overhead

1. With the development of ____ technology, a single chip was equipped with two or more processor cores. a. multicore b. multimedia c. networking d. multiprogramming

multicore

1. In indexed storage, when a file is created, the pointers in the index block are all set to ____. a. zero b. null c. the beginning of the volume d. the end of the volume

null

1. A(n) ____ in the busy list occurs when a memory block between two other busy memory blocks is returned to the free list. a. blank line b. empty entry c. null entry d. joined entry

null entry

1. One approach to performing compaction is to do it when a certain ____ of memory becomes busy. a. bit b. byte c. area d. percentage

percentage

1. A ____ server hides important network information from outsiders by making the network server invisible. a. fire b. proxy c. blocking d. redirection

proxy

1. Single-user, fixed partition, and dynamic partition memory schemes share unacceptable fragmentation characteristics that were resolved with the development of ____. a. best-fit algorithms b. deallocation c. null entry accounting d. relocatable dynamic partitions

relocatable dynamic partitions

Single-user, fixed partition, and dynamic partition memory schemes share unacceptable fragmentation characteristics that were resolved with the development of a. null entry accounting b. best-fit algorithms c. relocatable dynamic partitions d. deallocation

relocatable dynamic partitions

1. In a relocatable dynamic partition scheme, the ____ contains a value that must be added to each address referenced in a program so that the system will be able to access the correct memory addresses after relocation. a. compaction register b. load register c. bounds register d. relocation register

relocation register

1. Although a user directory is treated as a file, it is flagged to indicate to the File Manager that this file is really a ____ whose records are filenames that point to files. a. database b. subdirectory c. master file directory d. volume

subdirectory

To access a location in memory when using segmented memory management, the address is composed of two entries: a. the line number and the displacement b. the segment number, the line number, and the displacement c. the segment number and the displacement d. the segment number and the line number

the segment number and the displacement

1. A(n) ____ is created by a process, and it can be scheduled and executed independently of its parent process. a. thread b. program c. instruction set d. miniprocess

thread

1. Transfer rate of a magnetic tape is measured in inches per second (ips) using the following formula: transfer rate = density * ____. a. transport speed b. average access time c. block size d. sector size

transport speed

1. Memory defragmentation is performed by the operating system to reclaim fragmented space. True False

true

1. Assume that jobs A-D arrive in the READY queue in quick succession and have the CPU cycle requirements listed below. Using the SRT algorithm, the average turnaround time is ____. Arrival time: 0 1 2 3 Job: A B C D CPU cycle: 6 3 1 4 a. 2.5 b. 6.25 c. 7.75 d. 9.0

6.25

1. A general rule of thumb for selecting a proper time quantum in Round Robin scheduling is that it should be long enough to allow ____ percent of the CPU cycles to run to completion. a. 20 b. 60 c. 80 d. 100

80

1. The ____ demonstrates that when using a FIFO policy, in rare cases, adding more memory to a system can cause an increase in page interrupts. a. Belady Anomaly b. Paging Anomaly c. Laszlo Anomaly d. Interrupt Anomaly

Belady Anomaly

1. The formula for computing the current byte address (CBA) for a direct access file with fixed record length is ____. a. CBA = RN * RL b. CBA = (RN + 1) * RL c. CBA = RN / RL d. CBA = (RN - 1) * RL

CBA = (RN - 1) * RL

can be thought of as being an intermediary between main memory and the special-purpose registers, which are the domain of the CPU. a. Cache memory b. Segmenting c. Virtual memory d. Paging

Cache memory

1. The ____ is a hardware flag that must be tested by the CPU to determine when a device has completed an operation. a. Device Status Word b. Channel Interrupt Word c. Channel Status Word d. Device Polling Word

Channel Status Word

1. The ____ uniquely identifies each resource, starts its operation,monitors its progress, and, finally, deallocates it, making the operating system available to the next waiting process. a. Keyboard Manager b. File Manager c. Device Manager d. Memory Manager

Device Manager

1. ____ developed the Banker's Algorithm. a. Havender b. Holt c. Lane & Mooney d. Dijkstra

Dijkstra

is a dynamic-priority preemptive scheduling algorithm built to address the critical processing requirements of real-time systems and their pressing deadlines. a. Shortest Job Next b. Round Robin c. Variable Time Quantum Per Queue d. Earliest Deadline First

Earliest Deadline First

1. A firewall typically sits between a network and its individual computers. True False

False

1. A relative filename is a name that is selected by the File Manager when the file is created. True False

False

1. A seek strategy for an I/O device handler is the predetermined policy that the device handler uses to allocate access to the device among the many processes that may be waiting for it. It determines the order in which the processes get the device; the goal is to keep transfer time to a minimum. True False

False

1. An optical disc drive spins at a constant speed—this is called constant linear velocity. True False

False

1. Batch systems date from early computers, when each job consisted of a stack of chips entered into the system as a unit known as a stack. True False

False

1. General-purpose operating systems such as Linux or Windows are used in embedded systems. True False

False

1. In a file management system, information is passed from the Device Manager at the top of the hierarchy to the File Manager at the bottom. True False

False

1. Intrusion detection is an example of a strategy for improving system survivability based on knowledge gained from intrusions. True False

False

1. Onboard systems are computers that are physically placed inside the products that they operate to add features and capabilities. True False

False

1. Paged memory allocation offers the advantage that it doesn't require the entire job to be stored in memory during its execution. True False

False

1. Partial network encryption, also called communications encryption, is the most extreme form of encryption. (T/F)

False

1. The Memory Manager is in charge of main memory , widely known as ROM. True False

False

1. The content of a random access memory (RAM) chip is nonvolatile, meaning that it is not erased when the power is turned off. True False

False

1. The first-fit algorithm assumes that the Memory Manager keeps only one list containing free memory blocks. True False

False

1. The fixed partition scheme does not require that the entire program be stored contiguously and in memory from the beginning to the end of its execution. True False

False

1. The job of the I/O control unit is to keep up with the I/O requests from the CPU and pass them down the line to the appropriate control unit. True False

False

1. The shortest remaining time (SRT) algorithm is often used in interactive systems. True False

False

1. With demand paging, if there are no empty page frames available, to move in a new page, one of the current resident pages must be placed into main memory. True False

False

1. The transition from ____ is initiated by the Job Scheduler according to some predefined policy. At this point, the availability of enough main memory and any requested devices is checked. a. RUNNING to WAITING b. HOLD to READY c. READY to RUNNING d. RUNNING back to READY

HOLD to READY

1. A ____, used in RAID Level 2, is a coding scheme that adds extra, redundant bits to the data and is therefore able to correct single-bit errors and detect double-bit errors. a. Redundancy code b. Parity code c. Synch code d. Hamming code

Hamming code