rhl03.htm

linux的初学电子书

<P>Another problem that can occur is with SCSI devices (and a few others, although much rarer) that must have specific settings in the kernel image. Some kernels were compiled with settings that are default values for adapters or disk drives; if the 
settings have been changed, the kernel will hang up. This is often the case with special-purpose kernels that have been developed for non-mainstream adapters. To check for this type of problem, you should investigate any documentation that came with the 
kernel image.

<BR>

<P>The most common devices in a PC (COM ports, parallel ports, and floppies) and their IRQ, DMA, and I/O addresses are shown in Table 3.1. These are the default values for a PC, but they may be changed by users. Because only two COM ports (serial ports) 
are usually supported by DOS, they share IRQ values. The I/O addresses are different, though. Both floppy disks share the same I/O addresses, IRQ, and DMA.

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<P ALIGN=CENTER>

<CENTER>

<FONT COLOR="#000080"><B>Table 3.1. Common IRQ, DMA, and memory address settings.</B></FONT></CENTER>

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<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

<I>Device</I>

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

<I>IRQ</I>

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

<I>DMA</I>

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

<I>I/O Address </I><I>(Hex)</I></FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

COM 1 (/dev/ttyS0)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

4

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

N/A

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

3F8</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

COM 2 (/dev/ttyS1)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

3

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

N/A

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

2F8</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

COM 3 (/dev/ttyS2)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

4

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

N/A

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

3E8</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

COM 4 (/dev/ttys3)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

3

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

N/A

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

2E8</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

LPT 1 (/dev/lp0)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

7

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

N/A

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

378-37F</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

LPT 2 (/dev/lp1)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

5

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

N/A

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

278-27F</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Floppy A (/dev/fd0)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

6

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

2

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

3F0-3F7</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Floppy B (/dev/fd1)

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

6

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

2

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

3F0-3F7</FONT>

</TABLE><P>Network cards, SCSI adapters, sound boards, video cards, and other peripherals all must have unique IRQ, DMA, and I/O addresses, which can be difficult to arrange with a fully loaded system. For more information on available values, you should 
check your device or card-<A NAME="I2"></A>installation manual for recommended values and potential conflicts.

<BR>

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<A NAME="E68E24"></A>

<H3 ALIGN=CENTER>

<CENTER>

<FONT SIZE=5 COLOR="#FF0000"><B>SCSI Problems</B></FONT></CENTER></H3>

<BR>

<P>SCSI is one of the most versatile interfaces, and it pays for that versatility in potential problems. Linux is usually good about reporting problems with SCSI devices, although the error messages may leave you wondering about the real cause of the 
problem.

<BR>

<P>Table 3.2 lists many of the common SCSI errors and their probable causes. Find the message that closely matches the error message Linux displays in this table to determine your corrective steps.

<BR>

<BR>

<P ALIGN=CENTER>

<CENTER>

<FONT COLOR="#000080"><B>Table 3.2. Common SCSI problems and their solutions.</B></FONT></CENTER>

<BR>



<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

<I>Problem</I>

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

<I>Probable Solution</I></FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

SCSI device at all possible IDs

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

One or more devices are at the same SCSI ID as the controller. Check and change device IDs. Controllers should be ID 7.</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Sense errors

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Probably caused by bad termination. Check that both ends of the SCSI chain are terminated. If that is not the problem, the cable is likely at fault.</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Timeout errors

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Usually caused by a DMA, IRQ, or I/O-address conflict. See the preceding section for more information.</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

SCSI adapter not detected

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

The BIOS is disabled or the SCSI adapter is not recognized by the kernel. Check the drivers.</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Cylinders Beyond 1024

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Your disk has more than 1,024 cylinders, which the PC BIOS can't handle. Linux can use more than 1,024 cylinders, but it can't boot from a partition that extends across that cylinder boundary.</FONT>

<TR>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

CD-ROM drive not recognized

</FONT>

<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>

Some CD-ROMs require a CD in the drive to be recognized properly. Insert a CD and reboot.</FONT>

</TABLE><BR>

<A NAME="E69E28"></A>

<H4 ALIGN=CENTER>

<CENTER>

<FONT SIZE=4 COLOR="#FF0000"><B>Booting Linux</B></FONT></CENTER></H4>

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<P>If you have installed Linux and the system won't boot properly from your hard disk, it may be a problem with LILO or with the partitions. If you created a boot floppy, boot from that. If that boots without a problem, check the partition table by 
executing fdisk. Make sure the Linux partition is active. If it is