15. Frequently Asked Questions

15.1. XF68 or XF86

What is right, XF68 or XF86?

I have got a lot of questions conserning the name of the X-server in the installation program. I have called it "XF68_FBDev". On some CDs the server has got another name, "XF86_FBDev". The reason for this naming convention and confusion is purely historical. The Linux Frame Buffer Device was first developped on m68k Macintoshes, and the XFree86 server for the device was hence called XF68_FBDev. Later on the Frame Buffer Device was ported to other platforms like the x86 clones and PowerPC. What is the right name? The question is left as an exersice for the reader.

15.2. There is "snow" on my X desktop

How can I configure X so it removes the "snow" on my desktop?

The easy answer is: You can't. The kernel frame buffer device made by David Monro is still in an early stage, though working very well. Distortions in the picture when moving the mouse or scrolling a window are perfectly normal at eg 1024x768@60Hz. If you are a hacker, please fix it and post a patch to David. We would all love it very much.

15.3. I can't get my hardware to work

How can I get my new ultra whizbang XYZ card to work?

The 7248 is a PC-like box with ISA and PCI interfaces, so one should think that using "normal" PC hardware made for the x86 platform should work flawlessly. Sadly to say, it doesn't. The drivers often have to be ported, and there are not that many Carolina motherboard kernel hackers out there. In addition, much hardware made for the x86 platforms uses BIOS calls to work properly. As the 7248 and its relatives does not have such a BIOS, it's extremely difficult to get this hardware to run under Linux. Note: Linux-2.4 has fixed many of these problems. See below.

That said, there are working hardware for this box that runs with Linux. For questions about this, please contact the Workstation list, see Section 13.

Update: With the latest versions of the Linux 2.4 bk development tree (NOT the official Linux 2.4 sources), many of the problems stated above are fixed, and much more hardware is supported. For example did I put a standard eepro100 card in my box, and it worked flawlessly. This means you can use the 7248 for example as a packet-filtering firewall. I've also heard rumours on plain standard ISA Soundblaster cards working. Try and see if your card works. If it's interesting, send me an email, and I'll put a note here. See Section 12 for notes on building and installing a 2.4 kernel.

15.4. Me wants another distro!

Why do you not support more distributions in your howto?

There is one easy answer for this: I have not got the time to do this. I got LinuxPPC-1999 to work on my 7248 a year or so ago, and have not changed away from LinuxPPC since then. I plan to install Debian some time in the future, and have tried both SuSE and Yellow Dog, and have found that much of the steps are quite equal. The most troublesome part is to get the machine to boot the installation program. From there, each installer should do the job more or less itself. Getting X and sound to work should be more or less similar for all distributions, so just read the steps in this howto and try to make it work on your own. Feedback for this document is very welcome.

15.5. Boot floppies on other distributions

Can I use the floppies mentioned in this howto for other distributions

The bootfloppy mentioned in this howto should have support for all the hardware in the 7248, so you should be able to boot any distribution which uses the same floppy based installation scheme, that is, with the installation program on a ramdisk on one or more floppy disks. This means you should be able to boot LinuxPPC, SuSE, Yellow Dog and Debian with the bootimage. You have to have each distributions own installer ramdisk floppies, though.

15.6. The PReP boot partition?

Where should I mount the PReP boot partition?

To be able to understand the answer for this question, it's important that the reader understands how the 7248 boots into Linux. This is a three step procedure. First, the Firmware (which behaves in the same way as a PC BIOS) looks for something to boot. Usually, it should check the floppy drive, the CD drive, and then the first SCSI disk. On the SCSI disk it will look for a special partition called a PReP boot partition. On this partition, it will read the first program it can find there. If this is a Linux kernel bootloader, it will read and run this, and then the bootloader boots Linux. From here, Linux is in charge.

Many have asked where they should mount the PReP boot partition (the type 41 partition). This is a common misunderstanding. The PReP boot partition, usually located on /dev/sda1, should NOT be mounted anywhere. The files on this partition, usually only a single Linux kernel with a static linked kernel loader, are only used by the firmware when booting. The operating system does not use these files after the kernel has booted, so there is no need for mounting that partition.

Some people mix the meaning of the /boot directory and the PReP boot partition. Both use to contain kernels, but their use are different. /boot is used for storing kernels for later use, and for bookholding system info. The /boot directory is NOT read by the Firmware at boot time, so changing the contents of this directory does not change the way the Firmware loads Linux.

To be able to load a new kernel, you have to replace the existing kernel on the PReP partition. This is done with the dd command, see Section 10 for details.

15.7. It won't boot at all. Could it be bad RAM?

The machine won't boot at all. I suspect the RAM could be the problem. What kind of RAM should I use for this box?

The 7248 and it's cousines with Carolina motherboard do use special RAM, more specifically, they use only parity RAM. David Monro states that is is possible to make them work with other types of RAM if you remove the cache. Look at Section 13 for details.