GMU IT 342 Final Exam Key Terms and CYUs 7 - Roundup (Holdener)

Aliases

a special type of file in a Macintosh system that points to a specific file.

B-tree

a self balancing tree data structure

Controlled sharing

the ability to share the file with end users and programs in a manner that also protects the contents from others.

Directory

a cataloging structure in a file system used to reference other files.

Efficient

You can quickly get to the data.

Extents

a contiguous range of clusters somewhere on the disk, described by a starting cluster number and a length (how many clusters after the starting one). They keep track of where a file's contents are located on the disk.

Fields

collection of data that has the same type and similar function.

File

collection of data that is available for use at some point in the future by one or more programs.

Hard links

a mapping between a name and a file.

iNode

a data structure in a file system that describes a file or directory.

iNumber

the file number of a file in a -nix system, the index used as the first step in locating a file.

Long-term existence

data survives Operating System, hardware, and program changes as well as untoward events to the system.

Named data

the ability for end users and application programs to provide names to the data.

Path

a string of characters used to identify the location of a file or directory in a system.

Records

collection of fields about the same object.

Reliability

data is present and is correct.

Shortcuts

a special type of file in a Windows system that points to a specific file.

Soft links

symbolic links that map a file name to another file name.

Volume

a collection of physical storage devices that constitute a file system.

Address translation

the process by which a virtual address is converted to a physical address.

Base register

a CPU register that holds the initial storage location for a grouping of continuously stored data.

Best fit

a dynamic memory algorithm that places processes in the smallest hole (empty location) of memory in which it will fit.

Bounds register

a CPU register that defines the end of a continuous grouping for stored data.

Clock

a page replacement algorithm that modifies the FIFO algorithm by ensuring the candidate page has not been used since the last time the frame was checked. It differs from second chance in the means it is implemented (a circular queue).

Concatenation

a simplified method of addition that puts things together as a connected series.

Dynamic partitioning

a method of memory allocation that puts processes in a single variable-sized partition to maintain separation from other processes. The size of the partition is tailored to the process.

First fit

a dynamic memory algorithm that places processes in the first hole (empty location) of memory in which it will fit.

First in, first out

a page replacement algorithm that swaps out the page that has been in memory the longest.

Fixed partition

a method of memory allocation that puts processes in a single partition to maintain separation from other processes. The size of the partition remains fixed at the size it was set during start-up.

Frame

a fixed-length continuous block of physical memory that stores a single page, most times shortened to this single word.

Hole

in dynamic memory schemes, locations of unused memory that are ready for allocation to a program.

Least recently used

a page replacement algorithm that swaps out the page that has not been used for the longest time.

Next fit

a dynamic memory algorithm that places processes in the first hole (empty location) of memory from the last touched memory area in which it will fit.

Optimal

a page replacement algorithm that swaps out the page whose next use will occur farthest in the future.

Overlays

an overlay is a technique that allows the application programmer some control of what part of their program is in memory, it allows programs to be larger than the memory space allocated for the application.

Page

a fixed-length contiguous block of virtual memory.

Page frames

a fixed-length continuous block of physical memory that stores a single page, most times shortened to a single word.

Page reference string

a list of pages of a process that are referenced in sequence.

Page table

a data structure used to store a mapping between pages (virtual) and page frames (physical).

Page table pointer

the physical address of the beginning of the page time for a process.

Relocation

the ability of a memory system to move sections of memory around without any effect to the program.

Second chance

a page replacement algorithm that modifies the FIFO algorithm by ensuring the candidate page has not been used since the last time the frame was checked. It differs from clock in the means it is implemented (a linear queue).

Thrashing

a condition in virtual memory systems when virtual memory must continuously be swapped out of physical memory to accommodate new requests. In the worst case, the system never gets to use a page because it is swapped out before being used.

Translation lookaside buffer

a memory cache that stores the recent translations of virtual memory to physical memory.

Worst fit

a dynamic memory algorithm that places processes in the largest hole (empty location) of memory in which it will fit. Obviously, this is the largest hole in existence at the time.

Compiler

a program that translates code from one language into code of another language, primarily used to translate high-level languages into machine code.

Heap

a large pool of memory from which dynamic memory allocations occur.

Multiprogramming

a computing technique that enables multiple programs to be loaded concurrently into a computer and gives the end user the impression that they are all simultaneously running.

Process

the instance of a computer program that is being executed in a computer system.

Process control block

the overhead space used by an Operating System to store all the information about a single process.

Process control table

the overhead space used by an Operating System to store all the information about a single process.

Program

a sequence of instructions that have been formatted for a specific microprocessor originating from a programming language.

Semantics

the meanings of words and word relationships in a programming language.

Speed up

the increase in performance over a single-core system as a result of parallel execution.

Stack

an area of memory typically used for local procedures fixed variables.

Syntax

the set of rules that are provided for a programming language.

Von Neumann machine

John von Neumann provided a computer architecture in 1945 that consisted of a processing unit, control unit, memory, external mass storage, and input/output mechanisms. Today, it is commonly agreed to mean any architecture that uses stored instructions.

7.1 What is a file attribute?

Metadata about a file.

7.1 What use are file attributes to the Information Technologist?

They can be used to determine untoward activities on the system.

7.1 The two biggest issues with using files are:

Performance and corruption.

7.1 What is one method a file system uses to determine which application program applies to a file?

The last three or four characters after the stop character determine the application program.

7.1 What is a file?

A collection of data for use in the future.

7.2 What is a directory?

A cataloging system used to reference files.

7.2 Which of the following types of paths is shortest?

Either, not enough information.

7.2 Which of the following could not be a volume?

File

7.2 How would you change the working directory of your system?

Through the cd command.

7.2 If the current working directory from figure 7.4 were Programming, what would be the relative path to the directory Fixed Wing?

./../../../Personal/RC Models/Fixed Wing

7.3 Updating a file allows a user to

modify, delete, or add to the files data

7.3 While sharing allows a user to access another user's files, security seeks to:

Keep track of the user's actions

7.3 A simple security mechanism uses

read, write, and execute.

7.3 What is not part of file security?

Digital Rights Management

7.3 Methods of sharing include

copying, third-party software, and hard links.

7.4 What is the internal fragmentation of a 26,934-byte file in a system with 1 KB blocks?

2.6%

7.4 A file system can work with only

an indexing and free space management system.

7.4 Transactions and journaling help with what aspect of a file system?

Integrity

7.4 With spanned blocking,

multiple secondary memory blocks may contain parts of the same record.

7.4 Locating a file involves

recursively locating each directory to the file from the root.

7.5 What is one security flaw in NTFS?

File contents can be fully in the MFT

7.5 What two techniques are required to ensure files are managed?

Indexing and Free space management

7.5 In the FAT file system, where are attributes stored?

FAT

7.5 The Apple File System indexes with

B-trees.

7.5 In the FFS file system, where are attributes stored?

In the iNodes

8.1 Why do microprocessors not directly control memory anymore?

The speed of microprocessors has outpaced memory.

8.1 What does an overlay offer?

The ability to use programs larger than the available memory

8.1 What is Logical Memory?

Memory that is set up by software and used by programs.

8.1 The advantages of virtual memory do not include

increased access time

8.1 Types of physical memory include all except

DROM

8.2 If the base register is 1D2F5 and the virtual address is CD4, what is the physical address?

1DFC9

8.2 If the base register is 5C65E and the virtual address is 24E, what value must the limit register contain for the physical address to be valid?

Must be less than 5C8AD

8.2 What is the point of address translation?

To convert the virtual address to a physical address

8.2 Which are located in the microprocessor

Base Register and Limit Register

8.2 What advantage does concatenation offer in translation?

Speeds up the calculation

8.3 Fixed partitioning methods suffer from

internal fragmentation

8.3 (T/F) Performance in paging always improves as the number of page frames increases.

FALSE

8.3 Dynamic portioning methods suffer from

external fragmentation

8.3 Which method allows for the most control over protection?

Paging

8.3 Paging allows for

Relocation

8.4 What is the internal fragmentation for a 5,754,234 program with 1 MB pages?

8.5%

8.4 What would cause a page fault to take twice as long as normal?

A dirty page

8.4 What is the most reasonable page reference string?

222222222222233333333333333333