Hi,
I'm having problems when installing Linux to a two hard drive PC. I'm installing Linux on one drive - it seems that some versions of Linux insist on changing the partition table on the second drive, which should not be any part of the install. So far I've tried Fedora (FC4) and Ubuntu 5.1 - I havn't tried other distros yet (I'm hoping I can get some pointers before trying things at random as I've already spent quite a bit of time on this).

I’m trying to install Linux to a dual-boot system with two hard drives, installing Linux on the first drive alongside Windows. However installation of Fedora changes the geometry on the second hard drive which doesn’t have any Linux partitions. This then causes errors when I boot to windows and run partition magic.
What I was expecting was for Fedora to not touch the second hard drive partition table at all. Being a newcomer to Linux, I'd like some advice, especially as to whether this is a bug that should be reported. I’ve searched through the bug reports and not found anything for FC4.
Back in 2004 I tried FC2 and it gave the same problem (albeit using a different hard drive). I decided to wait a while before trying again – but it seems the problem is still present.
I thought that this may be related to the CHS bug (see http://lwn.net/Articles/86835/ ) but a) this bug is supposed to be closed and b) I've tried specifying the geometry but I still get the same effect.
The problem also seems to be limited to Fedora - I tried a minimal Ubuntu (5.1) install, and that didn't modify the partition table on either drive.

Details are below. Any help would be much appreciated as I’d like to get Linux up and running – at the moment I dont trust what would happen to my data if I were to carry on using Fedora as I dont know if my partition table may suddenly get changed again.

Any ideas on whether this is a bug that should be reported somewhere?

Thanks very much,
Victor


My Setup
I have two drives, one is a small (1.5Gb) HD connected to the motherboards IDE second channel as a slave. This is formatted with a small primary FAT partition and an extended partition containing a small Linux swap partition and the rest is formatted as Ext2. The BIOS is set for LBA for this drive.

The second drive is a 160Gb drive with multiple partitions (a FAT16 pri (DOS), a FAT32 pri (Win98), an NTFS logical, three FAT and several FAT32 logical partitions). This is connected to an ATA PCI card (Highpoint driverocket 133SB). This has no way to set/change LBA access - the manufactures documentation says it supports LBA48.


Both drives have XOSL on the MBR and were formatted with Partition Magic. (I’ve read many posts/articles that caution against mixing partitioning tools and to stick to one).

I installed Fedora (minimal install), selecting manual partitioning & selecting the preformatted Ext2 as the root mount point & told it not to reformat. I put GRUB in the root partition.


Results
After the install and adding Fedora to the XOSL menu, Fedora booted up ok.

The installation of FC4 does not change the partition table of the (small) drive to which FC4 was installed (/dev/hdd). However, it does change the PT of the large (160Gb) hard drive (/dev/hdg).

The changes to the large hard drive started at the first EPBR in the extended partition - that and all subsequent EPBRs had the start head/sector entries changed from [Head 0, Sector 1] to [Head 254, Sector 63].
Booting into Windows (or DOS) and running Partition magic gave error 116 (LBA and CHS values not equal). Partition magic also showed the Ext2 partition (on the first drive) FULLY occupied, with no free space.

I have tried this several times:
• without specifying the disk geometry;
• specifying geometry as reported by fdisk -l for both drives (viz. "linux hdd=787,64,63 hdg=19457,255,63");
• specified the 1.5Gb drive as reported by fdisk -l and specified 160Gb drive as its true physical geometry as determined by the drive manufacturers (Western Digital) s/w (viz. "linux hdd=787,64,63 hdg=310101,16,63")

After each install, the start head/sectors were changed on the large hard drive as described above. Note that I was installing to the small hard drive - so Linux shouldn't have touched the large drive at all.

I'm not going to trust the drive after the partitions values have been changed - I havn't noticed problems with windows - yet, but I don't like the fact that the specific partioning tool is not happy with the changes made. (I can edit the partition table back, I'm just not going to use Linux until I can resolve this).
I've also heard of many people having problems mixing partitioning utilities so I'd like to stick to the one. (I use partition magic as I primarily use windows98 - I'm just sampling linux for the first time).

I think this is related to Fedora since I've tried the Ubuntu install and it didnt change any partition table (other than marking the root as bootable of course). BTW, I couldn't see any way to specify the disk geometry to Ubuntu, so that was a straight minimal install.

TIA.

I think you will have a problem of mixing an old 1.5Gb disk with a 160Gb disk anyway, as the small disk may have a difficiulty to work in LBA mode with the large disk. It is true FC4 has an issue of working with "old" hard disks with number of heads and sectors other than 255 and 64.

I believe when an OS is booted from the first bootable disk it will have a set of rules for establishing the geometry for the rest of the hard disks. In your case some mother board could enable one geometry setting with 1.5Gb hard drive as the first bootable disk and a different setting if the 160Gb drive is opted to boot first.

The second problem, which you are already aware is the use of Partition Magic. Not good to stick with it because it does understand all the Linux partitions. My guess is your partition tablecorruption was caused by PM and may not be entirely related to FC4.

I think you can achieve stability by sticking with 160Gb as the first boot disk and avoid using PM. From experience cfdisk plus fdisk are the bomb proof partitioning tools. Changing to the 160Gb as the first bootable disk can cause problem to your Windows and may require a partial re-installation as the disk order will have been changed but it is better for long term stability. Changing Linux systems on it is easy as it involves only the amendment of the disk/partition reference in the boot loader and fstab files.

I would keep an eye on the small disk and if I want an OS in it I would put Puppy or Damn Small Linux as 1.5Gb is not big enough for any full blown Linux. This disk is better off as a USB device but put it in an external casing.

For 160Gb your disk should have 255 heads and 64 sectors per head.

Thanks for that Saikee, Some good stuff there.

I didn't know that FC had a problem with mixing large and small drives. I would have thought that seperately specifying the geometry of each drive FC would allow each drive to be treated independantly. I'm using the small drive just to test Linux installs, I don't intend to actually run things off that drive - as you say, its too small to do anything sensible with.

I'm pretty sure the partition table corruption is being caused by the Linux install and not partition magic since a) I check the partition geometry change with Partinfo (one of the DOS tools that come with partition magic) and AFAIK this is not capable of writing to the disk, and b) the geometry is not changed if I install Ubuntu.

I've been using PM since I've been a Windoze user so far. I wouldn't mind switching to another partitioning tool as long as I could run it off a bootable CD, floppy etc. I'd also want it to be graphical and have the ability to resize partitions. In your experience how do fdisk/cfdisk measure up to that - and would Qtparted be an option (for the graphical interface)?

I won't be able to make the 160Gb drive the first booting disk since I have to run it off the driverocket IDE card (the motherboard BIOS doesnt recognise drives > 137Gb). It seems that the motherboard IDE controllers always get recognised before the PCI card IDE controller, so it always gets allocated /dev/hdg. As I'm planning on eventually putting Linux and windoze on the 160Gb drive (once I sort out the partition table corruption) this shouldn't be a problem.

I'll try specifying Sectors of 64 instead of 63 and report back.

I still think that this is a bug since FC4 is changing the partition table of a drive on which it is not being installed. IMHO thats rather naughty.

Oh, BTW, over the weekend I wanted to see if perhaps GRUB was causing the problem, so I tried again, this time choosing not to install GRUB at all. The partition table on the second drive was still changed. So it seems not to be related to GRUB.

> I won't be able to make the 160Gb drive the first booting disk since I have to run it off the driverocket IDE card (the motherboard BIOS doesnt recognise drives > 137Gb).

I'm running an 80 MB drive with an IDE controller which can "see" only ~8 GB of it. No problem - OS can see and use it, just make sure boot stuff is on "visible" part of HDD.

It was widely acknowledged when FC4 was first released that it altered the hard disk geometry during installation instead of conforming to the as-used geometry by the existing systems. I didnot run into it as I had large disks which worked in LBA by default.

Your motherbpard should give hda to hdd designations to the 4 onboard IDE devices, leaving hde and hdg for the plug-in controller. That is normal. If your mobo supports it you should be able to instruct the Bios to boot hdg first if desire.

I can confirm that mixing large and small disks can cause the strange behaviour in Bios. It happened to me in one machine regular as clockwork. I believe that may have to do with the logic of the system because the disk geometry changes whenever I swap the disk order. I was mixing 200Gb with 30Gb/60Gb disks.

Wow. I didn't know Linux could do that. I wish I knew that before - I could have saved myself buying the controller card. Still, Windoze seems to need it and it didn't cost me much.

The documentation for the controller card says it supports LBA48 - I'm assuming its running in that mode.

It doesn't seem to support that.

From a previous post you suggested
I gave that a try last night - "linux hdd=787,64,64 hdg=310101,16,64" and didnt install GRUB - I still got the same corruption of the second hard drive. It seems rather strange that FC is even writing to the second hard drive. I hadn't heard of this issue before.