Question:

Hi. Got any undocumented tips for installing eComStation 1.2?

Answer:

eCS 1.2 installs easily on most systems. Migration over an existing Warp4 or eCS 1.1 installation works in most cases. However, as always, there are a few nits.

One of the more interesting failures is a Trap E in either DANIS506 or IBM1S506 shortly after the kernel begins to boot from the CD. The trap has only been reported for a few Thinkpad models when installing to a disk that has been factory partitioned by IBM and have never been touched by LVM or FDISK

The trap occurs when the partition data is not sufficiently consistent for the driver to determine the drive geometry from just the drive content. When this occurs, the driver queries the BIOS for the true geometry. The driver accesses the BIOS via a miniVDM. When creating a miniVDM, the kernel maps 8KB of memory at the upper end of the 640KB lower memory area. This mapping is required because many BIOSs load code or data into this area. The mapping is limited to 8KB because at this point in the boot process, virtual memory is a scarce resource. On the Thinkpads that trap the total memory required by the BIOS and the MEMDISK code exceeds 8KB. This is not a problem, unless the miniVDM is asked to make a BIOS access. The code path results in an attempt to execute code outside the 8KB area and the system traps.

There are several ways to avoid the trap.

If you are booting with DANIS506, you can supply the /!BIOS option and the BIOS access will be bypassed. This option is not supported by IBM1S506. If you use this option, check that the chosen geometry is the correct geometry.

If you have a bootable DFSEE CD or diskette, you can repartition the drive with DFSEE.

If you have a diskette drive on the trapping system, you can use the MAKEDISK utility to create a set of boot diskettes.

Finally, if you can install the drive in another system, you can use DFSEE, LVM or FDISK to repartition the drive.

Once the drive has been repartitioned, the partition data should be consistent and the BIOS access will no longer be required. The eCS 1.2 install CD should then boot without problems.

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