Re: GCR <--CP/M --> MS-DOS and vice versa?

[Charlie <Charlie_member@newsguy.com>]

In article <ozmdnZg_la3ScvWjXTWcoQ@comcast.com>, "Bill says...
>
>
>> > since technically an Apple based disk editor could read sectors from
>> > Apple CP/M, Pascal, ProDOS, Dos3.3, and often DOS 3.2.1 disks.
>> >
>> > A better comparison is a DVD/CD compared to a 45 record
>> > both about the same size with cylinders or a spiral
>> > but neither is hardware compatible.
>>
>> DVDs, CDs and 45 records all use a spiral not cylinders.
>>
>> Charlie
>
>What?!, DVD and CD use spiral?

Yep!

>What about the 650 mb floppy
>you can make on a CD writer with CD/RW disks? Are they also
>spiral? I think not.

Yeah, they are spirals too. CD/CD-RW/CD-R/DVDs are mechanically pressed with a
spiral groove when they are manufactured.  CDs and DVDs have the data "pits"
pressed at the same time.  The CD-Rs and CD-RWs have a blank groove.
To anticipate your next question, DVD-RAM, DVD-R, DVD-RW and DVD+RW all use a
similar spiral groove technology. DVDs can have two grooves, one on each side.

>Anyway, where can I read about that? I never
>heard that before.

Scott Mueller's "Upgrading and Repairing PCs" 14th Edition has a whole chapter
(almost 100 pages) devoted to DVDs and CDs.

Charlie