Difference between revisions of "Boot-parameters"

__NOTOC__

= Boot Parameters =

== How to boot from SCSI Hard drive ==

This issue is more related to SCSI raid on servers, and an indication that it is happening is the following message at boot time, just after grub is launched.

<pre><nowiki>

Volume group "VolGroup00" not found

</nowiki></pre>

The way to fix this issue is adding to the kernel the `scsi_mod.scan=sync` parameter.

== How to enable extra serial ports ==

There are some systems that might use the ttyS4 and/or ttyS5 known in other worlds as COM5 and COM6 respectively. By default these ports are detected under Linux.

To enable the extra serial ports go into the BIOS, find the serial ports and write down the following data:

* IRQ

* PORT

With this info, add the following line for COM5 and above to `/etc/rc.d/rc.local`, make sure to place them before the elo driver command lines.

<pre><nowiki>

setserial /dev/ttySn irq N port 0xDDDD uart 16550A baud_base 115200

</nowiki></pre>

Where:

* ''n'' is the number of the COM minus 1 (ttyS4 = COM5)

* ''N'' is the IRQ

* ''DDDD'' is the port number in hexadecimal format with 4 digits (2d8 = 02d8)

Then, tell the kernel that will have 6 ports on system running. To have done this edit the `/etc/grub.conf` file and add at the end of the kernel line the variable ''8250.nr_uarts=6''. The entry looks like:

<pre><nowiki>

...

title Bashlinux

root (hd0,0)

kernel /vmlinuz-2.6.18-92.el5 ro root=LABEL=/ rhgb vga=792 quiet 8250.nr_uarts=6

initrd /initrd-2.6.18-92.el5.img

</nowiki></pre>

== How to enable graphic cart at boot time on AMD Geode ==

On AMD Geode LX based terminals, the graphic card doesn't works with the standard frame buffer driver, that means the parameters `xdriver=vesa vga=792` won't work, or maybe yes but soonest will turn blank the screen and stop to work.

To solve this issue on AMD Geode terminals add to the kernel the `lxfb.mode_option=1024x768` parameter. ''1024x768'' could be changed to match the size of current monitor.

== How to setup screen size on Grub bootloader ==

In order to display small fonts on terminal is necessary to set the vga value as kernel parameter to enable the frame buffer vga mode, the following table shows the possible values:

<pre><nowiki>

Color depth | 640x480 800x600 1024x768 1280x1024

-----------------+-------------------------------------

256 (8bit)| 769 771 773 775

32000 (15bit)| 784 787 790 793

65000 (16bit)| 785 788 791 794

16.7 Mill.(24bit)| 786 789 792 795

</nowiki></pre>