On Monday 15 September 2003 09:20, Pigeon wrote: > On Sun, Sep 14, 2003 at 09:23:47PM +1200, cr wrote: > > On Sunday 14 September 2003 12:39, Pigeon wrote: > > > On Sat, Sep 13, 2003 at 04:33:22PM +1200, cr wrote: > > > > It'd be nice to have a self-contained floppy with just the basic > > componenets needed to boot a Linux system, so there's room to add a few > > utilties of ones choice. I've done that with my DOS floppy. But > > reading the HOWTOs, it seems that creating a Linux boot disk is a rather > > more complex procedure. > > And the kernel takes up half the disk, so there's less space for the > utils.
Yes, quite, but I really only wanted to put cfdisk on it. Never mind. Since I'm now only using fdisk as a means of hiding and unhiding partitions from DOS, I guess it should manage that okay. > CD-ROMs are easier, it seems (if the box can boot them) - I've even > made a bootable Linux CD in Windoze - a mate was playing with his new > Nero and wanted to try out the facility for making bootable CDs, so we > fed it a Linux boot floppy to get its boot image from and it worked > fine! > > > I guess the workaround is to use one of the pre-made disks like tomsrtbt, > > and just put my own utilities on a floppy that I can mount afterwards. > > At least, unlike DOS-booted-from-a-floppy, I imagine the Linux rescue > > systems don't constantly nag you to "Insert disk with COMMAND.COM in > > Drive A:" or whatever the Linux equivalent would be ;) > > > > Umm, just tried, with Leka's system running and a DOS floppy in the > > drive. mount -t msdos /dev/fd0 /floppy > > mounting /dev/fd0 on /floppy failed: no such device > > But it's got a /dev/fd0 there, I checked. I'm probably forgetting > > something important. Ah well, fdisk it is ;) > > My shot in the dark would be to wonder if, to save space, this floppy > uses an old/small version of mount that reports "no such device" where > one would expect "mount point xxx does not exist", and there's no > /floppy? Thought of that. Made a /floppy. Still no change. > > > For a boot floppy with cfdisk on it I use the resc1440.bin boot floppy > > > image off the Debian Slink installation CD. Unlike the Woody boot > > > image, it doesn't require a root filesystem supplied from another disk. > > > > I had a look on my various Linux CD's, and a look at Debian.org, but I > > couldn't find it. OTOH I may have missed it. I'll try putting cfdisk > > on a floppy and running it from that, after booting with a rescue disk. > > I'd have thought it'd be in the archives somewhere, but maybe you have > to download the .iso and pull it out of that... I could always email > you a copy. Would you object to receiving a 1.4 meg email? I think it would clog my mailbox, actually. Thanks for the offer. But the rescue disks I've got seem to do what I need for now. > > > > This is most unexpected... I grabbed a spare PC and HD from my latest > > > dumpster-diving expedition and experimented. The HD was only 2 gig, so > > > I reduced all the partition sizes by a third. Got the same result... > > > FDISK showing partitions swapped, and the second partition starts > > > "trying to recover allocation unit xxx" part way through where x >= > > > 25000 or so. > > > > Umm, but does this weird behaviour start at the same distance into the > > physical drive, or the same distance into the second partition, or the > > same percentage in? > > The same (more or less) number of allocation units into the second > partition. Not that it really matters, I think; it's a symptom of DOS > misbehaving, not the drive, and the important consideration seems to > be whether it happens rather than the precise details of how it > happens, unless we intend to hack DOS to cure it :-) Agreed, entirely. Just note it as another bug in DOS.... :) > > > Conclusion: DOS can't cope with the presence of non-DOS extended > > > partitions. How dead and chewed. > > > > > > So it seems that the options are something like: > > > > > > - don't have a Linux partition on that drive at all > > > - don't have your second DOS partition, so there can be room for the > > > ext2 partition to be a primary partition > > > - have two extended partitions, both DOS, and use umsdos in one of them > > > > Let me see - umsdos (and support for it is in my kernel, I just checked) > > will allow long filenames to be used *and* DOS can still read it, is that > > right? > > That is my understanding, although I've never used it myself. > Presumably under DOS you see something like pairs of files, possibly > with odd names, with the data in one and the Linux attributes and long > name etc. in the other. Rather like CD's and Windows 95 et al, I imagine. Not that I'm very familiar with them. > > I was intending to use the Linux partition as temporary space for mkisofs > > to put CD images for cdrecord to write to CD. It's handy to reserve a > > spare space of the right size that won't get imperceptibly filled up. I > > suppose the question now is whether mkisofs and cdrecord can work with > > umsdos. If not, no disaster, I'll just have to find 800MB somewhere else > > on the system. > > If that's all you're going to use it for, you might as well leave it > as FAT. I don't see any reason why that would interfere with cdrecord, > and if you're only ever going to have one large temporary file on > there the limitations of FAT don't really matter. Plus you could use > it for the same purpose in Windoze should the need arise. Yes, that has since occurred to me. > > > I thought DOS could only handle partitions of up to ~500MB (512? 528?). > > I must be wrong, it happily formatted 600MB, at least for partition 3. > > That's a BIOS limit to do with old BIOSes that don't do CHS > translation [properly]. DOS's limits are at 2 gigs for a partition and > 8 gigs for a drive. OK. Right. For once, DOS is innocent :) > > But anyway, this is the revised scheme: > > 1 Pri DOS 500MB Bootable DOS6.22 > > 2 Pri DOS 600MB W95 > > 3 Pri DOS 600MB W98 > > 4 Extended 5 DOS 500MB > > 6 DOS 800MB > > > > I'll see how it goes. > > > > 3 may get converted to FAT32 later. > > Should go OK, I'd think... that worked OK for me. Well, DOS created and formatted all those quite happily, which seems to confirm the theory that a non-DOS partition in the extended partition causes DOS to suffer strange errors. Not only DOS has glitches... I just tried (for the first time) booting off the hard drive rather than floppy, and now I remember I had GRUB on it when it was a Linux drive... so GRUB's still in the MBR. Since the rest of the disk has gone, GRUB promptly stalls when trying to load Stage 1.5... I guess I need to take GRUB off the MBR so it'll boot DOS so I can carry on with the install (makes a dive for the GRUB HOWTOs....) > > > It also seems I'd misremembered how the drive letters get allocated; > > > as you found out, the bootable primary partition is C:, the extended > > > DOS partition(s) come next and after them the other primary DOS > > > partitions. > > > > Does that sound like it spells 'kludge' ? ;) > > There's actually a file in the Microsoft Knowledge Base that explains how > > letters are assigned... if you have multi drives and multi partitions > > it gets fiendishly complicated. > > Yeah. I remember bits of it that I've learnt by experience... I've had > a Windoze system with a spare drive in it just to create/delete dummy > partitions on so I can keep the important drive letters where I want > them. I guess the trick is just to keep in mind, when setting DOS/Win paths, that swapping drives round can upset them. cr -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
