>The Apple CD/DVD Driver is only used to make the CD-ROM drive work once >MacOS is booted and running. It doesn't actually load until *after* the OS >has begun booting.
Not exactly. For the computer to read the OS et al from the device, a driver has to load at boot time, shortly after the bus is probed. On the Mac, bootable CDs do this the same way hard disks do - by having the driver stored in a small partition on the media. If you start up a Mac with a bootable CD in a drive, that driver will be loaded and used for any devices it supports. If you also have another driver - the same version or a different one - in the System Folder that boots, it won't load because all the devices it could handle are already taken care of (it's still a good idea to avoid this situation just in case, especially with different brands of drivers). This is true whether you boot the CD itself or another device; once the OS is starting up and loading extensions, the distinction is basically moot. This is why Toast requires you to locate a copy of the Apple CD driver extension in order to create a bootable CD-R - it essentially plucks the driver code from the extension file and writes it into a driver partition. >This point is slightly muddied if you have a drive that requires you to >select the CD-ROM in the startup disk control panel for it to boot. Even in >that situation, however, the driver is only needed to mount the drive so >that you can see it in the Startup disk control panel. It is not used in the >actual boot process. Quite right. In other words, the driver used to boot from a CD is the one that was stored on it (in the partition, not as an extension file) when the CD was pressed or burned. The state of your hard drive is irrelevant at that point (if it weren't, there'd be no way to boot from a rescue CD to fix a damaged filesystem). -- Marc Sira | [EMAIL PROTECTED] "If you can't play with words, what good are they?" ---------- Duo/2400 List, The friendliest place on the Net! A listserv for users and fans of Mac subportables. FAQ at <http://www.themacintoshguy.com/lists/DuoListFAQ.shtml> Be sure to visit Mac2400! <http://www.sineware.com/mac2400> To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> Need help from a real person? Try. <[EMAIL PROTECTED]> ---------- Dr. Bott | 10/100 Ethernet for your 2400 is finally here! MPC-100 | <http://www.drbott.com/prod/mpc100.html> NineWire | If they are cool enough to host this list... Digital Solutions | ...you should check them out! http://www.NineWire.com/ Midwest Mac Parts ][ <http://www.midwestmac.com> After-market parts for Macs. ][ 888-356-1104 ][ MacResQ Specials: LaCie SCSI CDR From $99! PowerBook 3400/200 Only $879! Norton AntiVirus 6 Only $19! We Stock PARTS! <http://www.macresq.com>
