Browse Definitions:
Definition

X (compact disc access time)

Contributor(s): Steven Raimi

In compact disc ( CD ) and digital versatile disc ( DVD ) technology, X is a base multiplier that expresses the speed with which data could be read (the read access time) from the compact disc in its original version, which was 150 kilobytes (KB) per second. As successively faster CDs arrived, manufacturers adopted the convention of indicating the read time in terms of the original speed. Thus, a 2X CD had a read access time of 300 KB per second and so forth. Our table relates each common drive speed to its read access time. It also shows the range of revolutions per minute (RPM) used to make the read access time possible.

CD/DVD Drive Speed Maximum Data Transfer Rate RPMs (revolutions per minute)
1X CD-ROM 150 KB/sec 200 - 530
2X CD-ROM 300 KB/sec 400 - 1060
4X CD-ROM 600 KB/sec 800 - 2120
8X - 12X CD-ROM 1.2 MB/sec 1600 - 4240
24X - 50X 1.8 - 6 MB/sec 2400 - 6360 approximately
1X DVD-ROM 1.25 MB/sec No exact data, but much slower than 1X CD-ROM

There are only minor increases in read access time as one moves from the 24X, 32X, and 40X drives. Higher rotation speeds are (somewhat) prone to noise and vibrations and may cause performance to vary from drive to drive.

It seems unlikely, because of these vibrations and performance variations, that read access times will increase much above present levels. Even though a hard drive can reach much faster speeds of rotation, its enclosure stabilizes the entire mechanism and therefore avoids much of the noise and vibration inherent in the open CD-ROM drive.

This was last updated in September 2005

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • PCAOB (Public Company Accounting Oversight Board)

    The Public Company Accounting Oversight Board (PCAOB) is a Congressionally-established nonprofit that assesses audits of public ...

  • cyborg anthropologist

    A cyborg anthropologist is an individual who studies the interaction between humans and technology, observing how technology can ...

  • RegTech

    RegTech, or regulatory technology, is a term used to describe technology that is used to help streamline the process of ...

SearchSecurity

  • Advanced Encryption Standard (AES)

    The Advanced Encryption Standard, or AES, is a symmetric block cipher used by the U.S. government to protect classified ...

  • identity theft

    Identity theft, also known as identity fraud, is a crime in which an imposter obtains key pieces of personally identifiable ...

  • spear phishing

    Spear phishing is an email-spoofing attack that targets a specific organization or individual, seeking unauthorized access to ...

SearchHealthIT

SearchDisasterRecovery

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

  • mass notification system (MNS)

    A mass notification system is a platform that sends one-way messages to inform employees and the public of an emergency.

  • disaster recovery as a service (DRaaS)

    One approach to a strong disaster recovery plan is DRaaS, where companies offload data replication and restoration ...

SearchStorage

  • CIFS (Common Internet File System)

    CIFS (Common Internet File System) is a protocol that gained popularity around the year 2000, as vendors worked to establish an ...

  • GlusterFS (Gluster File System)

    GlusterFS (Gluster File System) is an open source distributed file system that can scale out in building-block fashion to store ...

  • virtual memory

    Virtual memory is a memory management capability of an OS that allows a computer to compensate for physical memory shortages by ...

SearchSolidStateStorage

  • Tier 0

    Tier 0 (tier zero) is a level of data storage that is faster, and perhaps more expensive, than any other level in the storage ...

  • PCIe SSD (PCIe solid-state drive)

    A PCIe SSD (PCIe solid-state drive) is a high-speed expansion card that attaches a computer to its peripherals.

  • SSD caching

    SSD caching, also known as flash caching, is the temporary storage of data on NAND flash memory chips in a solid-state drive so ...

SearchCloudStorage

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close