[pocket-linux] Chapter 3 Question/Problem

[David Horton]

James Maki wrote:
> I have been going through the Pocket Linux as a means to learn more about
> Linux. I am a Linux newbie, but have been using computers for 20 years.

Just out of curiosity, what was your first computer?

> I
> was able to get the boot disk/root disk from chapter 2 to work as
> advertised. I am using the GRUB loader rather than LILO. I am creating the
> boot disks on a Fedora Core 1 system.
> 
> After creating the root disk several times, I automated with a BASH script.
> Creating the Chapter 2 root disk with the following script gives me a system
> that works as is should according to Chapter 2:
> 
> # SCRIPT ch2_bash.sh
> dd if=/dev/zero of=/dev/fd0 bs=1k count=1440
> mke2fs -m0 /dev/fd0
> mount /dev/fd0 /mnt
> cd /usr/src/bash-2.05a
> export CC="gcc -mcpu=i386"
> ./configure --enable-static-link --enable-minimal-config --host=i386-pc-linu
> x-gnu
> make
> strip bash
> mkdir /mnt/bin
> cp bash /mnt/bin/bash
> ln -s bash /mnt/bin/sh
> mkdir /mnt/dev
> mknod /mnt/dev/console c 5 1
> cd /
> umount /mnt
> echo "Script is DONE"
> # End of ch2_bash.sh
> 
> When I go onto Chapter 3 to create the compressed root disk, I use the
> following BASH script:
> 
> # SCRIPT ch3_bash.sh
> dd if=/dev/zero of=/dev/ram7 bs=1k count=4096
> mke2fs -m0 /dev/ram7 4096
> mount /dev/ram7 /mnt
> cd /usr/src/bash-2.05a
> make distclean
> export CC="gcc -mcpu=i386"
> ./configure --enable-minimal-config --host=i386-pc-linux-gnu
> make
> strip bash
> ldd bash
> #
> # Note the output from the ldd command. It should look similar to the
> example below.
> # bash# ldd bash
> # libdl.so.2 => /lib/libdl.so.2 (0x4001d000)
> # libc.so.6 => /lib/libc.so.6 (0x40020000)
> # /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
> #
> mkdir /mnt/bin
> cp bash /mnt/bin
> ln -s bash /mnt/bin/sh
> mkdir /mnt/lib
> strip --strip-unneeded -o /mnt/lib/libdl.so.2 /lib/libdl.so.2
> strip --strip-unneeded -o /mnt/lib/libc.so.6 /lib/libc.so.6
> strip --strip-unneeded -o /mnt/lib/ld-linux.so.2 /lib/ld-linux.so.2
> chmod +x /mnt/lib/*
> mkdir /mnt/dev
> mknod /mnt/dev/console c 5 1
> cd /
> umount /dev/ram7
> dd if=/dev/ram7 of=~/phase2-image bs=1k
> gzip -9 ~/phase2-image
> ls -l
> dd if=~/phase2-image.gz of=/dev/fd0 bs=1k
> echo " "
> echo "Script is DONE"
> echo " "
> # End of script ch3_bash.sh
> 

Good idea using scripts.  It saves time and typographical errors.

> The only discrepancy I see is that the ldd bash output gives the following:
> libc.so.6 => /lib/tls/libc.so.6
>   RATHER THAN
> libc.so.6=> /lilb/libc.so.6
> 

As far as I can tell this /lib/tls thing does not create a problem.  I 
have used Redhat 9.0 to build the pocket linux guide without any 
problems.  RH9 has the /lib/tls as well.

My understanding is that 'libc.so.6' is what the bash binary is actually 
looking for, not the full path.  Bash tells ld-linux.so.2, "Hey, I need 
libc.so.6" and it's up to ld-linux to figure out what file it is and 
what the path is.  ld-linux looks in /lib and /usr/lib by default.

So, in short, I don't think that is where the problem lies.

> When I use this Chapter 3 created boot disk, I get the following error after
> GRUB runs -
> kernel panic : VFS : unable to mount root fs on 02:00
> 
> If I try to mount the floppy with : mount /dev/fd0, I get the error message:
> mount: you must specify the filesystem type.
> 

I'm not a GRUB expert, but his error makes me think that your kernel 
might not have support for ramdisk or that the kernel option to load fd0 
into ramdisk is not being specified correctly in the grub config file. 
Try downloading and using the LILO bootdisk just to see if the problem 
is with the root disk or the boot disk.

> If I try to mount the floppy from chapter 2, it works.
> 
> The phase2-image.gz file is 758.9k on the hard drive
> Looking "inside" the gzipped file gives an image file of 8.0 MB.
> 

Are you sure the 8.0 is in Meg or is it in blocks?  Some commands give 
sizes in 512b blocks rather than kilobytes.  Just a thought.

> I do not understand all of the inner workings of all of the commands. Any
> hints or ideas as to the problem would be appreciated.  So far, this has
> been a great learning experience.
> 
> TIA
> 
> Jim Maki
> jwmaki at att.net
> 
> 

Glad to hear you are learning and enjoying.  Good luck tracking down the 
errors.

Dave