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Created 10 Nov 97

Autoplay
The mechanism in Windows 95 that lets CD-ROM and CD Extra discs start automatically when inserted in the PC. Autoplay works by a text file called AUTOPLAY.INF on the CD which tells Windows 95 which program to run when the disc is inserted. The BBC Music Magazine disc is 'autoplay enabled' and will run itself on a suitably configured PC. Autoplay can very slow on some PCs so wait a few seconds for the disc to appear. Other PCs have the facility disabled or not configured properly (some PCs don't have a signal saying the CD has been changed).

Blue book
The name of the standard document that describes the CD Extra CD format.

CD Extra
A CD format promoted by Sony, Philips, Microsoft, Apple and others that combines a music CD with a computer CD-ROM to the blue book standard. The discs have two sessions with audio tracks in the first part and computer data in the second and can be used without problem on an ordinary HiFi or CD Player (because the second session is invisible to such machines). The computer part of a CD Extra disc is available on a suitably equipped computer (not all PCs can read such discs properly). The computer part of a CD Extra is just like a CD-ROM and may or may not play on different types of computer just like any disc. Many CD Extra titles are both PC and Macintosh. The BBC Music Magazine CD at present is Windows PC only.

CD Plus
An old and obsolete name for CD Extra. The name still crops up but shouldn't be used any more.

CD-ROM
(Compact Disc - Read Only Memory) A CD that holds computer data; files and/or programs.

device driver, driver software
Software that controls a particular device. Device drivers are often separate small programs loaded as part of the operating system (e.g. Windows) and provide a standardised method for other programs to control the device. Device drivers may need to be updated to use a CD Extra disc because many PCs have older drivers that do not recognise the format even though they have an appropriate type of CD-ROM drive.

Enhanced CD
Generally taken to be any kind of CD which combines audio with computer data (e.g. pictures, lyrics or other materials) on one disc. The old way to make such discs was mixed mode, the growing new standard is CD Extra (aka CD Plus or Blue Book). Several alternatives have also been tried (pre-gap, track 0 etc). If someone uses Enhanced CD to mean a specific enhanced CD format, it's probably the CD Extra format that is referred to.

MCI
(Media Control Interface) A standard and set of software drivers in Microsoft Windows designed to make it easy for programmers to write software which controls multimedia and similar devices. The MCI interface provides CD audio, video, video disc, sound and similar services for programmers to use. The BBC Music Magazine CD Extra uses the MCI standard for playing CD audio. Under old versions of Windows (3.1 and 3.11), the MCI CD Audio driver may have to be added explicitly from the Control Panel; it's not necessarily installed on your PC to start with.

Mixed mode CD
A CD which combines CD-ROM with music by putting the computer data in track 1 and the audio in tracks 2 onward. This format has the advantage that it works with all PCs but the drawback that you have to start playing the disc from track 2 in a HiFi. Some HiFi players will automatically mute track 1, others will play the computer data as if it were music... this is unpleasant to listen to and can damage the HiFi's speakers. Mixed mode discs are still common for computer games and multimedia CD-ROMs but are increasingly a rare choice for enhanced music CDs.

Multisession
A single CD which has been recorded in two or more separate sessions. Each session is effectively a separate CD pressed onto the same physical disc though often computer software will make the sessions all appear to be one. A CD Extra disc uses two sessions; the first for the audio tracks, the second for the computer data.

Red book
The standard document that describes audio CDs.

Yellow book
The standard document that describes CD-ROMs.

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