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Problem Solving.

9. Problem Solving.

Here are some common problems that people have seen, together with the solutions.

Reading MS-DOS floppies from the Evaluation Board Debug Monitor.

Some of the older versions of the Evaluation Board Debug Monitor (pre-version 2.0) have a problem with DOS format flopies generated from Linux. Usually, the Debug Monitor can load the first few sectors all right, but then goes into an endless loop complaining about "bad sectors." Apparently, there is an incompatibility between the DOS file system as expected by the Debug Monitor and the Linux implementation of DOSFS. To make the long story short: if you run into this problem, try using DOS to write the floppy disk. For example, if loading the file MILO.cab doesn't work, use a DOS machine, insert the floppy and then do:

     copy a:MILO.cab c:
     copy c:MILO.cab a:
     del c:MILO.cab

Then try booting from that floppy again. This normally solves the problem.

MILO displays a long sequence of O> and does not accept input.

This usually happens when MILO was built to use COM1 as a secondary console device. In such a case, MILO echo output to COM1 and accepts input from there also. This is great for debugging but not so great if you have a device other than a terminal connected. If this happens, disconnect the device or power it down until the Linux kernel has booted. Once Linux is up and running, everything will work as expected.

MILO complains that the kernel image has the wrong magic number

Older versions of MILO did not support the ELF object file format and so could not recognise an ELF image and this might be your problem. If this is reported, upgrade to the latest MILO that you can find. All 2.0.20 and beyond MILOs support ELF. On the other hand it could be that the image is indeed damaged. You should also note that MILO does not yet automatically distinquish between GZIP'd and non-GZIP'd images; you need to add the ".gz" suffix to the file name.

MILO prints "...turning on virtual addressing and jumping to the Linux Kernel" and nothing else happens

One obvious problem is that the kernel image is wrongly built or is built for another Alpha system altogether. Another is that the video board is a TGA (Zlxp) device and the kernel has been built for a VGA device (or vice versa). It is worth building the kernel to echo to COM1 and then connecting a terminal to that serial port or retrying the kernel that came with the Linux distribution that you installed.

MILO does not recognise the SCSI device

The standard MILO images include as many device drivers as are known to be stable for Alpha (as of now that includes the NCR 810, QLOGIC ISP, Buslogic and Adaptec 2940s and 3940 cards). If your card is not included, it may be that the driver is not stable enough on an Alpha system yet. Again, the latest MILO images are worth trying. You can tell which SCSI devices a MILO image has built into it by using the "show" command.

MILO is unable to read your ext2 filesystem

Early versions of MILO are unable to read ext2 filesystems that have been created with the newer versions of mke2fs due to sparse superblocks. Upgrade to a newer MILO and this should fix the problem.