41 terms

Chapter 7 Vocab

Access Time
a measure of the amount of time it takes the computer to go out of a storage device, read a desired piece of information, and return that information to RAM memory.
Cloud Storage
An Internet based service that provides storage to users. The users seldom know where the data is actually stored and for all intents and purposes, it exists out in the cloud that is the internet.
Consists of two track sectors and is 512+512=1024 kb in size. These are the fundamental unit of allocation in magnetic disks.Thus, the file allocation table that acts as a table of contents to help the computer locate files on the disk uses the number of the cluster in which a file starts as an index for that file. All files are alloted an integral number of clusters even if they are not actually that big.
On a disk consisting of multiple platters, this the vertical extension of a track through all of the platters in the disk.
When you delete a file from the hard disk it leave a gap on the disk where the file used to be. When a new file gets written to the disk, part of it fills the gap and any remainder gets stashed elsewhere. when this happens, the file is aid to be fragmented. This works to restructure files on the disk so that they are no longer fragmented. This can make the disk perform better and can make the data on it more secure.
Disk Cache
Hard disks are very slow compared to modern chips. The access time of memory is measured in nano-seconds; whereas that of storage is measured in milliseconds. Thats a huge difference in speed. In order to bridge this disparity, most modern hard disks include some high speed memory that stores commonly and recently used items.
Disk Controller
The flow of information from the hard disk to system memory is managed by this. In order of increasing transfer rate, the three most commonly used busses are:
1. IDE (66MB/s)
2. SATA (150MB/s)
This is short for file allocation table and indicates a region of a disk in which file information is indexed. Depending on the type of disk it usually includes information such as the name of the file, the date it was last modified, the date it was created, its size, and the cluster index on which the start of the files resides.
Floppy Disk
A magnetic disk that stores information on soft plastic platters coated with magnetic material. These were mostly designed to be portable and carried from computer to computer.
This is the process of setting up the file allocation table for a magnetic disk. Most formats are high-level and do not actually erase the contents of the disk, they simply destroy the old FAT table and replace it with an empty one. Thus, the data is still on the disk and could be recovered by someone who knows how.
Hard Disk
A magnetic disk that stores information on hard platters, typically made of aluminum, coated with magnetic material.
Head Crash
Data on a magnetic disk is read by a set of read/write heads that float very close to the surface of the disk. If the disk is subjected to contaminants or vibration, the head may crash into the spinning surface of the disk and scrape off some of the magnetic coating that holds data. This can damage the disk and cause a user to lose data.
Stores documents as photographic miniatures on a single 8x11 sized sheet of film. Using proper viewer, the documents can be blown up so that they may be easily read.
Stores documents by taking pictures of them and recording the results on a roll of film. Using a proper reader the recorded images can be blow up so that they may be easily read.
The act of breaking a single physical disk into many separate logical disks that each have their own drive letter. Typically doing this must be done before the disk is formatted to setup the FATS.
The physical substrate that supports a layer of magnetic material in a storage device such as a hard disk. This must be strong enough to handle being rapidly spun, but can be made of flexible plastic such as that seen in a floppy disk or the solid aluminum disks found in hard drives.
It is short for Redundant Array of Independent Disks. In the modern world, data is more important than the hardware on which it is stored. If you don't believe this, consider the millions of dollars Amazon.com earns each day through the transactions it does on its web site. What is the value of 1-20 hard disks compared to million of dollars a day in sales? Given this, most companies decided to store their data redundantly on many disks, a RAID, so that the failure of one or even a few disk does not lose the information.
This uses to organize data on a spinning magnetic disk. It consists of a single pie shaped wedge. The amount of data located in each track that passes through the it is 512 kb.
Solid State Drives
Uses flash memory to store data, instructions, and information. These have faster access times and transfer rates than standard hard disks and also consume less power. The down side to these are that they are more expensive and have a higher failure rate.
Storage medium
Information can be stored on any material that can record two distinct states. For example, most modern storage devices use materials that are either optically active (CD/DV) or magnetic (hard/floppy disk). However, while it is really impractical, one could also use MMs or two kinds of candy to store data- all that matters is that it can hold 1s and 0s.
Stripping Data
A given piece of data is placed on several different disks in a RAID array. Thus, if any one disk goes down the data exists in several other places.
A narrow recording band on a magnetic disk.
Track Sector
The section of a track within a single sector. It is 512 kb in size.
Transfer Rate
Indicates exactly how much data can be read or written to a disk in a given time. For many storage devices, the read and write rates are not identical and the final transfer rate may be indicative of one or the other, or their average.
Mirroring Data
Used in RAID 1, this protects data on one hard drive by having it copied onto a second drive. Thus, RAID 1 system consists of two disks that are exactly identical to one another.
Tape is _______.
no longer used as a primary method of storage but is used most often for long-term storage and back up.
The use of microfil and microfiche provides all of the following except
they can be read without a microfilm or microfiche reader.
A storage technique that a DVD-ROM can use to achieve a higher storage capacity than a CD-ROM is to _______.
make the disc more dense by packing the pits closer together, be double sided, use two layers of pits, ALL of the above.
A _________ on a hard disk, such as that shown in the accompanying figure is made of aluminum, glass, or ceramic and is coated with an alloy material that allows items to be recorded magnetically on it surface.
A _________ occurs when a read/ write head touches the surface of a hard disk platter, such as that shown in the accompanying figure, usually resulting in a loss of data and sometime loss of the entire drive.
head crash
__________ time measures the amount of time it takes a storage device to locate an item on a storage medium.
A(n) ____ is a narrow recording band that forms a full circle on the surface of the disk.
A standard CD-ROM is called a ______disc because manufacturers write all items on the disc at one time.
The smallest unit of data a computer can process is a(n) _________.
The primary of advantage of the newer _______ interface is the cables are thinner, longer, more flexible, and less susceptible to interference.
Examples of nonvolatile storage media include all of the following except _______.
Some computers improve hard disk access time by using a(n) _______, which consists of memory chips that store frequently accessed items.
Disk Cache
A(n) _________ is the physical material on which a computer keeps data, instructions, and information.
Storage Medium
_________ measures the amount of time it takes a storage device to locate an item on a storage medium.
Access Time
A disk's storage locations consist of pie shaped sections, which break the tracks into small arcs called ______.
____________ is the process of dividing a disk into tracks and sectors, so the operating system can store and locate data and information on the disk.