[mu ANNOUNCE] muLinux v9r1b + tips

From: Michele Andreoli (m.andreoli@tin.it)
Date: Sun May 07 2000 - 17:06:40 CEST


Hi, friends.

I uploaded release 9r1b. Only mulinux.tgz and DOSTOOLS.zip changed.

I added in DOSTOOLS newly the boot.bat script, able to start muLinux
a the top of DOS.

I added also a new command/server: vcm, virtual console monitor. It is
only a 'poke' demo. This simple script is able to poke string at
fixed location in the video-ram. It shows, in the top-right corner of console,
time/date, free memory, uptime and received/trasmitted packets
across Ethernet interface. It is enabled via Setup/server.
I think, vcm is a pedagogical demo and can inspire other similar tricks
to someone, for example games, virus, etc...

Unfortunately, it isn't able to change colors using 'poke': a colored
monitor should looks better. If someone find a workaround, please
let me know.

The new 'poke' is able to insert strings, not only single bytes.
Example:

                # poke -c /dev/vc1 10 'ciao' 50 'mondo'

put the string 'ciao' in the file /dev/vc1 (the console #1), starting
from byte 10th, and the string 'mondo', starting from byte 50th.

2 cent Tip 1
-------------

Obvioulsy, a command like:

                # poke /dev/hda1 1 128 2 35 3 255 ....

may reprogram the Master Boot Sector of the primary hard-disk.

2 cent Tip 2
------------

Does someone on the list remember old BASIC listing, with DATA functions,
able to move code around the RAM? Well, now you can realize similar
things using a single shell program:

Using 'poke':
                #!/bin/sh
                PGM="1 128 2 35 ... (other 4-5000 pairs)"
                poke /tmp/cmd $PGM
                exec /tmp/cmd

Using hexd (the new one, from A. Costa)

                #!/bin/sh
                PGM="6162002e737472746162002e736873747274 ...."
                echo $PGM | hexd -d > /tmp/cmd
                exec /tmp/cmd

How to fill PGM? Easy:

                # PGM=`cat /bin/my_command | hexd -x`

2 cent Tip 3 : programs uncompressed on-the-fly
----------------------------------------
                prepare PGM
                # PGM=`cat /bin/my_command | hexd -x | gzip -c`

                #!/bin/sh
                PGM="6162002e737472746162002e736873747274 ...."
                echo $PGM | gzip -dc | hexd -d > /tmp/cmd
                chmod +x /tmp/cmd
                exec /tmp/cmd

Mmmm ... there is some limit on the variable storage in ash?

Michele

-- 
I'd like to conclude with a positive statement, but I can't 
remember any. Would two negative ones do?       -- Woody Allen
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