README for BigRAM Installation (rev 09.03.98)
version 0.1
asw 30.11.97

Introduction:

BigRAM is a set of four disks that contain files and compressed archives
to allow one to do a temporary installation of 32-bit networked Minix
2.0.0 on a large RAM disk.  This is useful for demonstrations and
beginning an installation via network.  It is also intended to be an
alternative for students who have access to machines outside of the lab
which they cannot repartition for a standard Minix installation.  The
BigRAM installation includes most of the standard Minix binaries,
including three editors and the Minix C compiler.  It also includes the
C libraries and header files and the man pages, so it provides an
environment adequate for simple programming assignments. 

Requirements: 

Intel 386 or better
10M or more of RAM (partially usable with less) 
1 1.44M floppy disk drive
optional: NE2000 or WD8003 compatible ethernet card 

How it works: 

Disk 1 is a boot disk.  The standard Minix installation boot disk
creates a RAM disk just big enough to hold a copy of the file system on
the boot disk.  The BigRAM boot disk makes an 8M RAM disk, copies
itself to this, and then starts Minix.  A shell and other essential
executable files are present, and the Minix startup script in /etc/rc
uses these to unpack compressed archives containing additional files.
After unpacking everything from the Disk 1 image the user is prompted
to insert Disks 2, 3, and 4 in turn, and additional compressed archives
are unpacked to fill the standard directories of a Minix installation.
At the end of this startup process the user is permitted to mount an
optional floppy disk on the /usr/home directory.  The process of
booting and unpacking the four standard disks takes less than 3 1/2
minutes on the system on which this distribution was developed.

Directories in the BigRAM distribution:

bigram/             -- top directory
      /README       -- this file
      /images/      -- the image files
      /imag.docs/   -- directory listings of disk contents  
      /arch.docs/   -- contents of various archives
 
How to use it:

Download the four image files (disk*.image) from the images directory.
If you are working on an MS-DOS or Windows system download fdvol.exe
from the regular minix/dosutil directory and use it to copy each of the
image files to a 1.44M floppy disk.  See the README file in the
minix/dosutil directory for information on using fdvol.  There are two
other utilities, rawrite and wrtdisk, which can be used instead of
fdvol if you prefer.  If you are working on an existing Unix-like
system like Minix or Linux that can write IBM-PC floppy disks you can
use dd or cat to write the images to floppy disks, for example:
  cat disk1.image > /dev/fd0 

Note that the floppy disks you use for the images must be perfect, with
no bad sectors.  Use brand new high quality disks and test them first.
You are writing an image of an entire file system, so ordinary programs
for copying files will not work, and ordinary operating system methods
for avoiding bad sectors are not available.

When the disks are ready you can boot from the disk to which you wrote
disk1.image.  If you have 10M of RAM or more you can press "=" when you
see the message and Minix will start.  

If you have less than 10M RAM press Esc to enter the boot monitor, and
use the "set" command to view the boot parameters.  Change the ramsize
parameter to reflect the size of RAM disk you want to use, reserving 2M
of RAM for ordinary use.  For example, if you have 8M of RAM, enter
"ramsize=6144".  The entire BigRAM installation requires about 7.5M.
If your RAM disk is smaller the entire installation will not fit, but
you may find that the result is still useful.  You can customize the
installation later to make best use of a more limited RAM.

While in the boot monitor you can change the DPETH0 (ethernet)
parameters if you need to.  If you don't know how to set up for your
ethernet just proceed, and read the boot (8) man page after you are
running, so you will know how to do it next time.

If you have made changes in the boot parameters you can give the
command "save" to write them to the disk.  If you don't save them the
modified parameters will be used this time, and then you will get the
defaults again the next time you boot.  Next type "boot" to start Minix.

When Minix has started it will inform you of its progress as archive
files are unpacked.  When everything from the first disk has been
unpacked you will be asked which disk drive will be used for the
remaining disks.  Enter "fd0" or "fd1" and then press Enter.  You will
be prompted to put disks 2, 3, and 4 in the drive in turn.  After all
four disks are loaded you will be invited to mount a floppy on
/usr/home; say "no" this time because you don't yet have a floppy to
mount.  Finally, you will be shown an IP (network) address and asked if
you want to change it.  If you want to use the network you should enter
an IP address usable on the network to which you are connected.
Finally, you can log in.  Three user accounts are available, root, bin,
and asw.  None of them require a password.  

Making a home disk:

To do real work you need a permanent home directory. Put a formatted 
disk into a drive and use mkfs to make a file system, for example:
  mkfs /dev/fd0 

Then mount the floppy on one of the directories provided for temporary
mounting ("M fd0" will mount it on /fd0).  The copy the /usr/home
directory to the floppy:
  cpdir -msv /usr/home /fd0

Now you can unmount the floppy from /fd0 ("U fd0") and mount it on
/usr/home.  You will have to be logged in as root and cd to the root
directory to do this.  You can use this disk for all work you want to
save, and mount it the next time you start the system.  Be sure to
unmount the floppy when you want to stop the system, so all buffered
files are written.  The easiest way is to use the shutdown or halt
commands before turning off the system.  Later you may want to create a
user account with your own name, but this requires modifying
/etc/passwd and then making a new etc.tar.Z file for disk 1, so it is
probably easiest just to work as asw for the time being.
 
Loose ends:

This is version 0.1, and was assembled while I was working at the
National Autonomous University of Nicaragua (UNAN) in 1997.  For this
reason some of the messages you may see and some comments inside
scripts will appear in Spanish.  Also, the selection of files to
include is not necessarily the best one for your purposes, so you may 
want to change the contents of some of the archives. 

It should be obvious how to change the archives: the original disks can
be mounted on /fd0 or another mount directory and an archive can be
expanded into a convenient directory, such as /usr/tmp, using zcat and
tar.  You can then add or delete files, and use tar and compress to
make a new archive and write it back to the floppy.  Be careful about
file sizes, however, some disks have very little free space.  You may
also have to delete some directories from the RAM disk to give yourself
working room; the include and man trees are good candidates.  Remember,
it's just a RAM disk, and everything will be there the next time you
start.

For your own installation you need to edit /etc/rc to use your correct
IP address, and /etc/hosts to include addresses of other hosts in your
network -- the current file contains an obsolete list of systems at the
UNAN.  You will then need to rebuild etc.tar.Z on disk 1 with your new
files.

TODO:

Ideally the various archives would be assembled and written to disks
using a script which consults easily edited lists of files to be
included.  

The same general scheme, loading compressed files into a large RAM
disk, can be used to advantage in installing Minix.  A much smaller
subset of Minix containing files and programs needed to run Minix on a
network can be used to boot Minix and start the hard disk installation,
with the bulk of the files installed via ethernet.

Juggling files between archives to make optimal use of the space on
floppy disks is a pain.  An alternative would be to load one or two
large archives using the vol program, which allows splitting of a file
image across multiple disks.  It is also probable that other
compression programs, such as gzip, would give better results than the
standard Unix compress.  While developing this approach I decided using
a larger number of small archives would be easier, and more flexible,
but other approaches should be tested.

Feedback:

BigRAM is an experiment.  I would appreciate feedback with suggestions of
any kind.  Even just a quick acknowledgement that you found the idea
interesting enough to get this far in reading the README would be
appreciated.  Please write to Al Woodhull, awoodhull@hampshire.edu. 

asw 09.03.98