Whats a multisession disc?
(2000/06/16) A session is a recorded segment that may contain one or more tracks of any type. The CD recorder doesn’t have to write the entire session at once — you can write a single track, and come back later and write another — but the session must be “closed” before a standard audio CD or CD-ROM player will be able to use it. Additional sessions can be added until the *disc* is closed or there’s no space left. Multisession writing was first used on PhotoCD discs, to allow additional pictures to be appended. Today it’s most often used with “linked” multisession discs, and occasionally for CD-Extra discs. These require a bit more explanation. When you put a data CD into your CD-ROM drive, the OS finds the last closed session on the disc and reads the directory from it. (Well, that’s how it’s supposed to work. Depending on your operating system and CD-ROM drive, you may get different results.) If the CD is ISO-9660 format – which it almost certainly is unless it’s a Macintosh CD wri
A session is a recorded segment that may contain one or more tracks of any type. The CD recorder doesn’t have to write the entire session at once — you can write a single track, and come back later and write another — but the session must be “closed” before a standard audio CD or CD-ROM player will be able to use it. Additional sessions can be added until the *disc* is closed or there’s no space left. This provides a simple and fairly reliable way to write some data to a disc now and still be able to add more later. The trouble with using multiple sessions is that, every time you write a chunk of data, you incur a fairly substantial amount of overhead: 23MB after the first session, and 14MB for every subsequent session. This overhead lead to the development of “packet writing”, which allows drag-and-drop recording, but works in an entirely different way (see section (6-3)). Multisession writing was first used on PhotoCD discs, to allow additional pictures to be appended to existing d
A session is a recorded segment that may contain one or more tracks of any type. The CD recorder doesn’t have to write the entire session at once — you can write a single track, and come back later and write another — but the session must be “closed” before a standard audio CD or CD-ROM player will be able to use it. Additional sessions can be added until the *disc* is closed or there’s no space left. Multisession writing was first used on PhotoCD discs, to allow additional pictures to be appended. Today it’s most often used with “linked” multisession discs, and occasionally for CD-Extra discs. These require a bit more explanation. When you put a data CD into your CD-ROM drive, the OS finds the last closed session on the disc and reads the directory from it. (Well, that’s how it’s supposed to work. Depending on your operating system and CD-ROM drive, you may get different results.) If the CD is ISO-9660 format – which it almost certainly is unless it’s a Macintosh CD written in HFS –
Please see one of the usual references for information on multisession (and on packet writing if you wish): the CD-R FAQ or the primer at my WWW site. Each session except the first that you write to a CD carries overhead of about 13 MB. You have two choices: do not close the session (which in practice means writing packets with Direct CD or equivalent), or accumulate enough before writing to make the overhead acceptable.
(2005/02/07) A session is a recorded segment that may contain one or more tracks of any type. The CD recorder doesn’t have to write the entire session at once — you can write a single track, and come back later and write another — but the session must be “closed” before a standard audio CD or CD-ROM player will be able to use it. Additional sessions can be added until the *disc* is closed or there’s no space left. This provides a simple and fairly reliable way to write some data to a disc now and still be able to add more later. The trouble with using multiple sessions is that, every time you write a chunk of data, you incur a fairly substantial amount of overhead: 23MB after the first session, and 14MB for every subsequent session. This overhead lead to the development of “packet writing”, which allows drag-and-drop recording, but works in an entirely different way (see section (6-3)). Multisession writing was first used on PhotoCD discs, to allow additional pictures to be appended
