mwandel@tiger.waterloo.edu (Markus Wandel) (04/10/90)
I've been wondering about this one for a while. In the 1.2 autodocs, there is a description of a simple, elegant autoboot scheme for disks. It involves the AddDOSNode() function, which is documented like this: ok = AddDosNode( bootPri, flags, deviceNode ) D0 D0 D1 A0 It is explained quite clearly that to enter a bootable disk into the system, all you have to do is build a device node for it, and enter it into the system via AddDosNode() before the DOS comes up. Then the system will attempt to boot off each bootable device, in order of boot priority, and start up on the one where it finds the first valid boot block. It says that to never boot one should specify -128 as the boot priority. What a nice scheme! Too bad it doesn't exist. What exists instead is a kludge. One has to manufacture a "Boot Node", point it to an autoconfig-related structure, which in turn points to some boot code in ROM. The AddDosNode() call can apparently not be used. There are no boot blocks, and the device with highest boot priority always wins. Moreover, the floppy disk is not at boot priority zero after all; (if memory serves) it is always checked first and a bootable floppy always overrides everything else. It seems that to implement the original scheme would have taken less code both on Commodore's part and on the part of the device driver implementers. So what happened to the original scheme? Why did it get abandoned? Does someone (out of the two or three people in the world who know) have a comment on this? Markus Wandel mwandel@tiger.waterloo.edu (519) 884-9547
mks@cbmvax.commodore.com (Michael Sinz - CATS) (04/10/90)
In article <23078@watdragon.waterloo.edu> mwandel@tiger.waterloo.edu (Markus Wandel) writes: [ deleted stuff about old docs... ] > ... There are no boot blocks, and the device >with highest boot priority always wins. Moreover, the floppy disk is not >at boot priority zero after all; (if memory serves) it is always checked first >and a bootable floppy always overrides everything else. ... The floppy has a boot pri of 5. If a hard drive is above that, the floppy will not be checked first. There is, however, a problem in the system in that the DF0: floppy will be in the device list twice if you boot from a hard drive that is higher than 5 pri. /----------------------------------------------------------------------\ | /// Michael Sinz -- CATS/Amiga Software Engineer | | /// PHONE 215-431-9422 UUCP ( uunet | rutgers ) !cbmvax!mks | | /// | |\\\/// "I don't think so," said Ren'e Descartes. | | \XX/ Just then, he vanished. | \----------------------------------------------------------------------/
dailey@cpsin2.uucp (Chris Dailey) (04/11/90)
In article <10740@cbmvax.commodore.com> mks@cbmvax (Michael Sinz - CATS) writes: [...] >The floppy has a boot pri of 5. If a hard drive is above that, the floppy will >not be checked first. There is, however, a problem in the system in that the >DF0: floppy will be in the device list twice if you boot from a hard drive >that is higher than 5 pri. I don't know how related this is, but... Why isn't the system bootable from DF1:? Will it be in 1.4? 2.0? Not that it's that important, but it would be nice. >| /// Michael Sinz -- CATS/Amiga Software Engineer | >| /// PHONE 215-431-9422 UUCP ( uunet | rutgers ) !cbmvax!mks | -- __ /..\ ('`) Chris Dailey /_/\_\ dailey@cpsin1.cps.msu.edu
mks@cbmvax.commodore.com (Michael Sinz - CATS) (04/12/90)
In article <1990Apr11.145009.10324@msuinfo.cl.msu.edu> dailey@cpsin2.uucp (Chris Dailey) writes: >In article <10740@cbmvax.commodore.com> mks@cbmvax (Michael Sinz - CATS) writes: >[...] >>The floppy has a boot pri of 5. If a hard drive is above that, the floppy will >>not be checked first. There is, however, a problem in the system in that the >>DF0: floppy will be in the device list twice if you boot from a hard drive >>that is higher than 5 pri. > >I don't know how related this is, but... Why isn't the system bootable >from DF1:? Will it be in 1.4? 2.0? Not that it's that important, but >it would be nice. It's in there... (Lower priorities, but...) /----------------------------------------------------------------------\ | /// Michael Sinz -- CATS/Amiga Software Engineer | | /// PHONE 215-431-9422 UUCP ( uunet | rutgers ) !cbmvax!mks | | /// | |\\\/// "I don't think so," said Ren'e Descartes. | | \XX/ Just then, he vanished. | \----------------------------------------------------------------------/