Dan wrote: > >At 11:34 PM -0500 04/01/2003, Mike wrote: >>Can someone briefly describe or list chronologically what takes place >>during start up/system boot. (Or refer me somewhere that has the >>info.) I am specifically interested in what gets power first and how >>the SCSI and PCI busses communicate with the system in determining >>the connected hardware. > >Brief? *snort* Easier to just paste. :) > >Apply power. > >Power supply charges capacitors then outputs stabelized dc power. > >CPU's RUN line is set, and its interrupt line is tapped. > >The first bootstrap runs from the ROM. > >It lights up the built-in video circuitry and starts the self-test routine. > >The self-test checks cpu integrity, rom integrity, ram integrity, and >basic mb and i/o bus responses. If it passes, you get a bong. If it >fails, you get a cord and/or a sad mac with an error code. <- audio >and video error message, just in case one or the other is foo. > >The first bootstrap initializes the ROM'd drivers for things like the >built-in ADB, USB, PCI, SCSI, and ATA buses. Each driver in turn >queries its hardware to make sure its alive. > >The strap then looks for a boot target, seeking in a priority order: >floppy, keyboard indication, or PRAM. If it finds one, it continues >the boot from there. At this point, if a target is not found, you >get a floppy icon with a question mark on the screen. The strap >intiates an query loop, walking up and down the buses until it finds >something usable. Regretfully, if anything is foo with the PCI or >SCSI buses at this point, Apple's boot usually just hangs. > >Once a target is found, the strap does a temp mount of the drive and >loads the full disk driver from a hidden partition. The disk is then >dismounted. It then remounts the drive, using the full driver. It >loads the big ROM image from the hard drive, if available. Then >switches to the secondary bootstrap in the big ROM. > >The secondary bootstrap loads the first chunk of the System file, >initializes the Managers, and switches to the INIT Manager (which >loads all extensions) (I think that's the right name). > >The scri files are loaded from the System Folder. These are >specialized system patches that MUST load first first first. eg: >System Enablers, Connectix Virtual, etc. > >Then items in the Extensions folder that contains INIT resources are >loaded alphabetically. Some display their icons in the crawl, some >don't. > >Likewise, Control Panels that contain INIT resources are loaded. > >Then loose items in the System Folder that have INIT resources are loaded. > >The INIT Manager exits, and the bootstrap loads and runs the Finder. >(...The bootstrap hangs around forever and keeps trying to run the >Finder, in an infinite loop. That's why the Finder automagically >restarts if you kill it!..) > >The Finder creates the desktop and formally mounts all local disk >volumes. As it mounts them, it does a few simple file system checks >(which is why the desktop can be slow to display sometimes). > >WHILE the Finder is starting up, OT's DHCP client triggers. >Everything is paused while the DHCP client talks to your DHCP server >to get its ip assignment and such. This pause may be less than 5 >seconds, but it could be up to two minutes. > >Then the Finder mounts remote disk volumes. > >Then the Finder launches all the things in the Startup Items folder. > >FWIW, >- Dan. > //What boots up must come down.//
Thanks for the better-than-expected very thorough answer! Curious where you copied and pasted it from? Mike -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
