Hi tim,
It's just a cut and paste of the FAQfrom the ELKS site...
May this help you...
Cheers;
Pat
-------
ELKS FAQ
This a list of answers to Frequently Asked Questions about ELKS, also known as
Linux-8086.
This FAQ is maintained by Alistair Riddoch, based on the origonal by Brian
Candler; please send all updates to
[EMAIL PROTECTED] The latest version of this document is available at
http://www.elks.ecs.soton.ac.uk/. Note
that ELKS is in the very early stages of development and this information is
likely to become out of date rapidly.
Additional information can be found at the ELKS home page at
http://www.uk.linux.org/ELKS-Home.
There is a mailing list. To subscribe, send a message to
[EMAIL PROTECTED] containing the words
subscribe linux-8086 in the body. As far as I am aware there is not currently a
working archive of the list, though
in the past archives were available from http://epocha.pd.mcs.net/Linux8086/ and
http://www.cyberpass.net/~dummy/robert/archives/linux-8086/.
Note that ELKS is not Linux, and the mailing list is not a suitable place for
posting questions about Linux (despite
its name). These would be better sent to one of the Linux-specific newsgroups
such as comp.os.linux.misc
Section 1 - General
Q1.1. What is ELKS?
Q1.2. How does ELKS compare with standard Linux?
Q1.3. Are there any ready-to-run distributions of ELKS?
Q1.4. Can ELKS run on an 8088?
Section 2 - Compiling and installing
Q2.1. Where can I find the source?
Q2.2. How do I make an ELKS kernel?
Q2.3. I get an error saying that /usr/include/linux/vm86.h does not exist
Q2.4. How do I make an 'init' for ELKS?
Q2.5. How do I make a root filesystem disk?
Q2.6. What if I have an XT with a 360K disk drive?
Q2.7. How do a change root device of boot images?
Q2.8. How do I install to a harddisk?
Q2.9. I get errors building Dev86 on recent Linux systems
Q2.10. I get errors building elkscmd.
Q2.11. I get warnings building elkscmd.
Section 3 - Using ELKS
Q3.1. Can I run bcc binaries under Linux?
Q3.2. Can I boot ELKS under DOSEMU?
Section 4 - Contributing to ELKS
Q4.1. Can I contribute to the ELKS project?
Q4.2. What needs to be done?
Q4.3. What is CVS?
Q4.4. How do I use CVS without an account?
Appendix A - Unanswered questions
This document may be freely distributed as long as this copyright notice is kept
intact and any changes or additions
are marked with your name
Copyright © 1997-1999
Maintained by Al Riddoch based on pages by Steffen Gabel
[INTRO] [FAQ] [DOWNLOAD] [HOME]
ELKS FAQ - Section 1 - General
Q1.1. What is ELKS?
ELKS is the Embeddable Linux Kernel Subset, a project to build a small kernel
subset Linux (which will
provide more or less UNIX V7 functionality within the kernel) that can run on
machines with limited processor
and memory resources. The initial proposed targets are the Intel 8086 and
eventually the 286's 16-bit protected
mode. A kernel that can run on this kind of hardware is useful for embedded
systems projects, for third world
deployment where 80x86 x>0 machines are not easily available, and for use on
various palmtops.
More information on the background, goals and current status of the project can
be found at the ELKS home
page.
Q1.2. How does ELKS compare with standard Linux?
ELKS is intended as a subset of true Linux, and ought to be small enough to be
understood by one person, so it
should be invaluable as a learning tool. It is in the very early stages of
development, and big chunks are missing,
such as swapping, shared libraries, and networking. Having said that, it is
already able to boot, provide virtual
consoles, mount a root minix filesystems floppy, provide basic serial and
parallel I/O, and start various small
programs.
Q1.3. Are there any ready-to-run distributions of ELKS?
Not yet. You need to use a standard Linux machine, download the sources, and
cross-compile to generate the
8086 target code. Boot and root disk images are provided with the current
version of ELKS, but all they do is
act as a platform for testing the system, very little can be done with them.
Michael Strates has volunteered to put
together a distribution, which he is currently working on.
Q1.4. Can ELKS run on an 8088?
The 8088 is identical to the 8086, except it has an 8-bit external data bus
instead of 16-bit (and thus is slower).
So yes, ELKS will run on it.
This document may be freely distributed as long as this copyright notice is kept
intact and any changes or additions
are marked with your name
Copyright © 1997-1999
Maintained by Al Riddoch based on pages by Steffen Gabel
[INTRO] [FAQ] [DOWNLOAD] [HOME]
ELKS FAQ - Section 2 - Compiling and Installing
Q2.1. Where can I find the source?
The primary site ftp://linux.mit.edu/pub/ELKS is now back up.
The primary site for Dev86 is http://www.cix.co.uk/~mayday/ which is the best
place to find the latest version.
Other sites where ELKS and Dev86 can be found are:
ftp://ftp.ecs.soton.ac.uk/pub/elks/
ftp://cam053212.student.utwente.nl/pub/8086-nix/ELKS/
ftp://tsx-11.mit.edu/pub/linux/ALPHA/linux-16/
ftp://src.doc.ic.ac.uk/packages/linux/tsx-11-mirror/ALPHA/linux-16/
ftp://ftp.amscons.com/pubi/mirrors/ELKS
ftp://mirror.aarnet.edu.au/pub/linux/elks/
If you know of any others or wish to set one up, please contact the maintainer.
Q2.2. How do I make an ELKS kernel?
Recent releases contain a conmpiled binary kernel which most people whould be
able to use for initial testing.
You should only need to compile your own if you wish to modify the kernel, or
change the configuration options.
The file boot in images.zip can be written to floppy with dd or RAWRITE.EXE to
make a kernel boot disk.
If you want to compile your own kernel, download dev86/Dev86-0.0.13.4.tar.gz and
kernel/elks-0.0.67/elks-0.0.67.tar.gz (or the latest versions) from
linux.mit.edu, or one of the other
sites. Unpack Dev86 them into /usr/src (or any other convenient directory), and
elks into /usr/src/linux-86
tar -xvzf Dev86-0.0.13.tar.gz -C /usr/src
tar -xvzf elks-0.0.67.tar.gz -C /usr/src
The development environment will be created in /usr/src/linux-86, and the kernel
source in /usr/src/elks. Next
you have to build the development tools, which include the bcc compiler:
cd /usr/src/linux-86
make install
Next, compile the kernel.
cd /usr/src/elks
# Build kernel
make config
make dep
make
Make config works in the same way as the main Linux kernel. The default
configuration will work on almost all
systems. Don't change any of the options unless you know what you are doing.
(If you're used to building Linux kernels with gcc, you'll be amazed at how
quick this is! :-) The result is a
floppy disk image called "Image", which you can copy to a formatted floppy and
boot from.
dd if=Image of=/dev/fd0
or
make disk
You should now be able to boot with this disk, but you won't get much further
without a root floppy disk for it to
mount. You can either use the image file root provided in images.zip, or make
your own. You'll need to use bcc
to compile an 'init' program and make a root minix filesystem. This is explained
further down.
Q2.3. I get an error saying that /usr/include/linux/vm86.h does not exist
Edit /usr/include/sys/vm86.h, and change #include <linux/vm86.h> to #include
<asm/vm86.h>
Q2.4. How do I make an 'init' for ELKS?
After the ELKS kernel has booted it will run /bin/init.
A real version of 'init' is being prepared for inclusion in the tiny-utils
package, also on linux.mit.edu. A very
basic init and login is included in the sysutils part of the elkscmd package
which is distributed with each
release. The kernel code has recently been changed so that it loads /bin/init
instead of /bin/sh.
To install init and login compile them both with
bcc -0 -O -ansi -s init.c -o init
bcc -0 -O -ansi -s login.c -o login
and copy them into the /bin directory of your root disk. login requires an
/etc/passwd and a /etc/group file, and a
/bin/sh (or other depending on the entry in /etc/passwd.
-0 selects 8086 code generation,
-O enables optimisation,
-ansi enables ansi-style function prototypes (only), and
-s strips symbols out of the binary.
As of kernel 0.0.56 sash now works and is being used as /bin/sh by most people.
It can be found in
elkscmd.tar.gz. For best results copy /etc/passwd and /etc/group from a standard
linux distribution onto your
root disk so that ls -l works okay, and /usr/lib/liberror.txt so that sash error
reporting works.
A version of ash is also included which does work under ELKS, but is much
larger, and may not work at all on
machines with <640K of memory.
Q2.5. How do I make a root filesystem disk?
For most people the root filesystem included in images.zip should be ideal, and
can be used to create a root disk
under Linux as follows:-
dd if=root of=/dev/fd0 bs=8192
or under DOS, RAWRITE.EXE can be used.
You need to create a minix floppy containing the appropriate bits and pieces.
This file should contain init, login,
and sh in /bin/ and passwd and group in /etc/, as well as three ttys for init in
/dev/.
Note: /dev/tty is different to normal Linux which uses (5,0)
mkdir /usr/src/root86 # make a directory
cd /usr/src/root86
mkdir dev # create directorys in it
cd dev
mknod tty1 c 4 0 # creatye the required devices
mknod tty2 c 4 1
mknod tty3 c 4 2
mknod fd0 b 3 128
cd ..
mkdir bin
cd bin
cp <path-to-elkscmd-init> init # copy in essential binaries
cp <path-to-elkscmd-login> login
cp <path-to-elkscmd-sash> sh
cd ..
mkdir etc
cd etc
cp <path-to-skeleton-passwd> passwd # add required files for login
cp <path-to-skeleton-group> group
cd ..
fdformat /dev/fd0H1440 # if floppy not yet formatted
mkfs.minix -n14 /dev/fd0 1440
mount -t minix /dev/fd0 /a # need a mount point "/a"
cp -pR /usr/src/root86/* /a
umount /a
Some distributions use /dev/fd0u1440 instead of /dev/fd0H1440.
You should removed passwords from the passwd file as they are not yet suported,
and make sure the shell entry
for each user is /bin/sh for future compatability.
Alternatively, if you have a 2.0.x kernel and mount-2.5k, you can use the
loopback filesystem to create a disk
image on your hard disk, and then dump it to floppy
dd if=/dev/zero of=root.image bs=18k count=80
losetup /dev/loop0 root.image
mkfs -t minix /dev/loop0 1440
mount -t minix /dev/loop0 /a
...
umount /a
dd if=root.image of=/dev/fd0
As of ELKS 0.0.53 floppy sizes other than 1.44M now work. Just follow the above
intructions substituting the
appropriate sizes in where required. However, because of the way 360K disks are
written by 1.2Meg drives,
the instructions below must be followed if you are trying to boot a machine with
a 360K drive.
Q2.6. What if I have an XT with a 360K disk drive?
Preparing boot and root images to run on a different machine requires a little
care, especially if the target
machine has a 360K drive. 360K drives (5.25" DD) have 40-track heads, and 1.2MB
(5.25" HD) have 80-track
heads. A 1.2MB drive can read 360K disks but not reliably write them, since it
will write magnetic tracks
which are half the width expected by a 360K drive.
One solution is to fit a 360K drive as the second drive in your Linux PC - you
can then format 360K disks with
fdformat /dev/fd1d360 and create filesystems as usual.
Otherwise, you will need to create a floppy disk image file, transfer it to the
PC which has the 360K drive (e.g.
using a serial cable), then use "rawrite" under DOS to recreate the disk from
the image file.
Boot disks
The 'Image' file can be written to any type of floppy disk and will boot
successfully, so all you need to do is
transfer the file and use 'rawrite' to make the target disk.
Root disks are now autodetected so you no longer have to re-compile for disk
sizes other than 1.44Mb.
Root disks
You can prepare a 360K root image on a larger drive - when you enter the mkfs
command substitute '360' for the
size of the filesystem. Once you have copied the files to this disk, unmount it,
then you can create a disk image
file from it:
dd if=/dev/fd0 of=root.image bs=1k count=360
This image can then be transferred to the target and written out using 'rawrite'
as before. If you use the loopback
filesystem this step is not necessary.
RAM limitations
0.0.44 expected there to be 640K RAM available. However if you do not have 640K
the problems with
DEF_INITSEG and DEF_SETUPSEG have now been fixed in later versions so you will
not have to change
anything.
Q2.7. How do a change root device of boot images?
Version 0.0.62 boot disk was compiled to use the second floppy drive as a root
disk because the
wait_for_keypress() function was broken. You can get round this if you only have
one floppy drive by using a
hex editor to change the root device no. in the image.
If you get an error about root disk mount failing on device 03c0, load the boot
image into a hex editor and look
for c003h somewhere near the start of the image and change it to 8003h. (c003h
is 03c0 in Intel's backwards
byte ordering). This should work for any version, but it is not clear whether
the address of the byte to edit varies
between version. [EMAIL PROTECTED] reports that in 0.0.62 boot image, the two bytes
are at 0adf - oade.
Q2.8. How do I install to ELKS to harddisk?
As of version 0.0.65 it is possible to install ELKS root disk on a harddisk and
then create a boot floppy that
uses this. There still some bugs but it is more usable than a root floppy.
First create a partition with fdisk. Any version of fdisk will be able to do
this, but the current root disk only
supports bd?1-4, which are primary partitions, and if you already have a DOS
primary partition you will not be
able to make a second primary partition with DOS fdisk. The version of fdisk
included on the ELKS 0.0.67 root
disk is still young code, but seems to work fine on my system.
Having created the partition, boot ELKS from boot and root floppies, and create
a filesystem using mkfs. It is
safe to use ELKS fdisk to check you know the correct device name for the
partition you want to create the
filesystem on. To create the filesystem type
mkfs /dev/bd?? <size>
where bd?? is the correct partition, and size is the size of the partition in
Kbyte blocks. <size> cannot be more
than 32M. E.g. To make a filesystem on the first partition on the slave disk,
which is a 20M partition type:
mkfs /dev/bdb1 20000
Now mount the partition on the /mnt mount point by typing
mount /dev/bd?? /mnt
where bd?? is the correct partition. The root directory of the new partition may
look a bit corrupted and it may
not be possibly to use ls from /mnt. I am not sure why mkfs is generating
slightly corrupt filesystems, but I am
working on it.
Create the essential directories on the new filesystem as follows:
mkdir /mnt/bin
mkdir /mnt/dev
mkdir /mnt/usr
mkdir /mnt/usr/lib
mkdir /mnt/mnt
mkdir /mnt/etc
mkdir /mnt/root
mkdir /mnt/home
mkdir /mnt/var
mkdir /mnt/var/run
mkdir /mnt/home/user?....
Now copy essential files. You will need many more than these for a decent system
but here are the essentials
and some of the more useful ones.
cp /bin/init /mnt/bin/init
cp /bin/login /mnt/bin/login
cp /bin/getty /mnt/bin/getty
cp /bin/sh /mnt/bin/sh
cp /bin/ls /mnt/bin/ls
cp /bin/pwd /mnt/bin/pwd
cp /bin/mount /mnt/bin/mount
cp /bin/umount /mnt/bin/umount
cp /bin/cp /mnt/bin/cp
cp /etc/passwd /mnt/etc/passwd
cp /etc/group /mnt/etc/group
cp /usr/lib/liberror.txt /mnt/usr/lib/liberror.txt
touch /mnt/var/run/utmp
Finally create the essentail devices:
mknod /mnt/dev/tty1 c 4 0
mknod /mnt/dev/tty2 c 4 1
mknod /mnt/dev/tty3 c 4 2
mknod /mnt/dev/fd0 b 3 128
mknod /mnt/dev/fd1 b 3 192
mknod /mnt/dev/bda b 3 0
mknod /mnt/dev/bda1 b 3 1
mknod /mnt/dev/bda2 b 3 2
mknod /mnt/dev/bda3 b 3 3
mknod /mnt/dev/bda4 b 3 4
mknod /mnt/dev/bdb b 3 64
mknod /mnt/dev/bdb1 b 3 65
mknod /mnt/dev/bdb2 b 3 66
mknod /mnt/dev/bdb3 b 3 67
mknod /mnt/dev/bdb4 b 3 68
Now unmount the new partition with
umount /dev/bd??
You will now need to re-compile a new kernel with the correct root device
selected. To do this edit
include/linuxmt/config.h in the ELKS kernel sources, and changed the
CONFIG_ROOTDEV from 0x380 to the
device number of the partition. The last two digits must be the minor number of
the partition in hex. The minor
number can be found from the list above in the far right column. E.g. The minor
number for bdb3 is 67, which is
43 in hex, so the ROOT_DEV value is 0x343.
Type
make disk
to build a new kernel floppy, and reboot the ELKS machine with this new boot
disk. The new root should
mount, but may give a warning, and the system come up as normal, but much faster
than from floppy. As before
the root directory may be corrupted, but it should be possible to change to
other directories normally, and the
system should work otherwise normally.
Q2.9. I get errors building Dev86 on recent Linux systems
There are two issues with building Dev86 on recent systems which are known to be
a problem under RedHat
6.0.
Firstly a conflict with recent glibc means that a FILE * can no longer be
initialised as pointing standard IO. I fix
is in the works for this problem.
The version of ar shipped with some Linux systems can no longer deal with bcc
format .o files. A new ar
program has been written for Dev86 and will be included in the next release. In
the meantime Greg Haerr has
made the new version available from
ftp://microwindows.censoft.com/pub/microwindows/ar .
Q2.10. I get errors building elkscmd
Errors similar to the following may be experienced building elkscmd if Dev86 was
not built correctly against a
recent kernel.
undefined symbol: _setsid
undefined symbol: _fchown
This is caused because the Dev86 did not pick up the list of system calls from
the current kernel source. A
similar problem can occur if Dev86 does not find the kernel include directories,
and build links to them in bcc's
standars include directory.
ps.c:2.26: error: cannot find include file linuxmt/sched.h
The solution to both these problems is as follows:-
Make sure the line near the top of the Dev86 top level Makefile that defines
ELKSSRC points to the
correct directory on your system.
Rebuild and re-install the libc portion of Dev86.
make library
make install-lib
Check that /usr/bcc/include/linuxmt and /usr/bcc/include/arch are links to
elks/include/linuxmt and
elks/include/arch respectively, wherever you happen to keep your kernel
source. If not, rmove the
directories, and put in the links manually.
rm -rf /usr/bcc/include/linuxmt
rm -rf /usr/bcc/include/arch
ln -s /usr/src/elks/include/linuxmt /usr/bcc/include
ln -s /usr/src/elks/include/arch /usr/bcc/include
Check that linux-86/libc/syscall.dat is the same as
elks/arch/i86/kernel/syscall.dat. If not copy the version
from the kernel into place to force it, and then rebuild and re-install
Dev86.
cd /usr/src/linux-86
cp /usr/src/elks/arch/i86/kernel/syscall.dat libc/syscall/syscall.dat
cp /usr/src/elks/arch/i86/kernel/syscall.dat libc/syscall/syscall.dev86
make library
make install-lib
elkscmd should now build correctly.
Q2.11. I get warnings building elkscmd
Warnings similar to the following may be experienced building elkscmd:-
ld86: warning: _utmpname redefined in file
/usr/local/bcc/lib/bcc/i86/libc.a(utnt.o); using definition in utent.o
These are caused because elkscmd contains patched version of files from the
standard C library. Once these
patched version have been well tested they will be integrated into libs, and
removed from Dev86.
This document may be freely distributed as long as this copyright notice is kept
intact and any changes or additions
are marked with your name
Copyright © 1997-1999
Maintained by Al Riddoch based on pages by Steffen Gabel
[INTRO] [FAQ] [DOWNLOAD] [HOME]
ELKS FAQ - Section 3 - Using ELKS
Q3.1. Can I run bcc binaries under Linux?
Yes - by loading a kernel module you can run ELKS binaries directly. This makes
development of programs to
run under ELKS much less painful, since you can test them on your normal Linux
system (although they might not
work under ELKS, if your program uses a kernel facility which is not yet
implemented)
cd /usr/src/linux-86/elksemu
make module
insmod binfmt_elks.o
Note that you will need to rerun the 'insmod' each time you reboot. There are
some sample bcc programs you
can try in /usr/src/linux-86/tests (such as a version of 'wc')
If when making the module you get an error saying "modversions.h: no such file
or directory" then you need to
edit the Makefile to remove the reference to this file, i.e.:
MODCFLAGS=-D__KERNEL__ -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer \
-fno-strength-reduce -pipe -m486 -DCPU=486 -DMODULE -DMODVERSIONS
Q3.2. Can I boot ELKS under DOSEMU?
Yes. ELKS can boot inside dosemu 0.63.1.36 running under Linux 2.0.7, and
probably other combinations as
well. Make sure your floppy drive is configured in /etc/dosemu.conf, and use the
-A flag to dos or xdos if
necessary to force a floppy boot.
floppy { device /dev/fd0 threeinch }
This document may be freely distributed as long as this copyright notice is kept
intact and any changes or additions
are marked with your name
Copyright © 1997-1999
Maintained by Al Riddoch based on pages by Steffen Gabel
[INTRO] [FAQ] [DOWNLOAD] [HOME]
ELKS FAQ - Section 4 - Contributing to ELKS
Q4.1. Can I contribute to the ELKS project?
Yes! Just like any other Open Source project, ELKS can always use more
volunteers. The system is quite simple
relative to Linux so even people with relatively little experience can make a
useful contribution.
ELKS is now managed using Source Forge which is an extremely useful service
offered by VA Linux. In order
to contribute to ELKS you will need to register for an account on Source Forge.
The ELKS project page on
Source Forge can be found here.
Q4.2. What needs to be done?
Some idea of jobs that have been identified can be gained by looking at the
Oustanding projects, and Bugs pages
on the main website. These pages are automatically generated from the TODO and
BUGS files in the kernel
source tree. Outside of the kernel there is alot of work to be done to put
together the linux 8086 distribution
which uses ELKS as its kernel. Most of the work involves porting existing
utilities to run under ELKS.
Q4.3. What is CVS?
CVS is the revision control system used to manage the source code of the elks
kernel and the elkscmd package.
You can use CVS to obtain the very latest version of the source code, loook
through the revision history, and
more experienced developers with accounts can use it to commit changes they have
made to the code.
ELKS CVS is now hosted on Source Forge. For details on getting an account see
the link on CVS from the
ELKS project page
Q4.4. How do I use CVS without an account?
Source Forge offer full anonymous CVS services by default. Full information can
be found on the CVS page
linked from the ELKS project page on Source Forge.
This document may be freely distributed as long as this copyright notice is kept
intact and any changes or additions
are marked with your name
Copyright © 1997-1999
Maintained by Al Riddoch based on pages by Steffen Gabel
[EMAIL PROTECTED] wrote:
> Hi, can anyone email me a FAQ on ELKS, I dont have www access so an
> url is no good.
>
> thanks.
--
Patrice Kadionik. F6KQH / F4CUQ
-----------
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