Place Knoppix into RAM when RAM >= 750MB? Now possible!

**cyrano** · 04-15-2003, 06:30 PM

Yes you would. Each time you boot your system, you'd have to load the contents of the CD into RAM from the HD. The way that knoppix works now, we load just the necessary parts of the CD into RAM using the CDROM. Maybe we only load 100MB worth of stuff, but using the CDROM to do it is slow. If we load the full 700MB of the CD into RAM using the HD, we will be loading more data, but HD access times are much faster than CD access times. Once your OS is fully loaded into RAM, launching any program would be lightning fast! Obviously, this approach is not meant for people that reboot their machines 10 times a day -- but if you boot once in the morning, or if you boot your machine and keep it up for several days, I think the benefit of the lightning fast program response times would outweigh the longer boot up.

**LinuxSam** · 04-17-2003, 12:20 AM

If you are to use the harddrive to store the files from the CD... why not make a real linux installation? No need to boot from the CD at all.

I don't really see your point in this...

/LinuxSam

**Henk Poley** · 04-17-2003, 08:53 PM

Originally Posted by LinuxSam

If you are to use the harddrive to store the files from the CD... why not make a real linux installation? No need to boot from the CD at all.

I don't really see your point in this...

I think there isn't one, unless you qualify " fun to thinker with".

btw, couldn't you boot Knoppix, load an fs into RAM, with everything symlinked to the CD. And then 'slowly' replace all symlinks with the 'real stuff'?

I do know this is impossible under Windows, apart from symlinking (which isn't that impossible btw). That's the reason why you need to reboot when you install software. Which reminds me of my Windows98 from RAM project

**Lex** · 07-25-2003, 10:34 AM

Now back to the topic: I have changed the linuxrc as Fabianx suggested: http://www.mathematik.unni-bielefeld...um0312/linuxrc
The file has been put back on the CD as he described.

BUT Knoppix boots as always, without loading the CD to the RAM (I have 1GB, Knoppix's limit is at 900MB).

Please take a look at the file and tell me what is wrong about it.

**Lex** · 07-25-2003, 04:58 PM

the correct URL is of course:

http://www.mathematik.uni-bielefeld.de/~num0312/linuxrc

The problem I have mentioned above is solved (boot.img was not set as the booting image).

So here is the next one:

error messages while booting:

Code:

Getting paths...Copying /cdrom to RamDisk, this will take a while ...
mount: Unknown option 'size=800M' ignored.
cp: writing `/cdrom2/Demos/Audio/opensource.ogg' : No space left on device
...  [no space left on device error messages]
cp: writing `/cdrom2/index.html : No space left on device
umount: Invalid argument
umount: Device or resource busy
insmod: a module named cloop already exists
/linuxrc: 442: Syntax error : end of file unexpected (expecting "fi")
FAT: bogus logical sector size 0
FAT: bogus logical sector size 0
Kernel panic: VFS: Unable to mount root fs on 01:01

I ran it this time in VMware virtual machine with 880 MB RAM with "knoppix 2" cheat code.

I will burn the image and try to boot the real PC and report here.

**Lex** · 07-25-2003, 05:19 PM

the same errorrs on the real PC

It seems like mount does not want to create a RamDisk

**Fabianx** · 07-26-2003, 11:46 AM

Originally Posted by Lex

the correct URL is of course:

http://www.mathematik.uni-bielefeld.de/~num0312/linuxrc

The problem I have mentioned above is solved (boot.img was not set as the booting image).

So here is the next one:

error messages while booting:

Code:

Getting paths...Copying /cdrom to RamDisk, this will take a while ...
mount: Unknown option 'size=800M' ignored.
cp: writing `/cdrom2/Demos/Audio/opensource.ogg' : No space left on device
...  [no space left on device error messages]
cp: writing `/cdrom2/index.html : No space left on device
umount: Invalid argument
umount: Device or resource busy
insmod: a module named cloop already exists
/linuxrc: 442: Syntax error : end of file unexpected (expecting "fi")
FAT: bogus logical sector size 0
FAT: bogus logical sector size 0
Kernel panic: VFS: Unable to mount root fs on 01:01

I ran it this time in VMware virtual machine with 880 MB RAM with "knoppix 2" cheat code.

I will burn the image and try to boot the real PC and report here.

Heh! Thats great that you actually try it!

Sorry, it was a shot in the air. I will try to fix the remaining issues and see form you nice error report, what did go wrong

)

And I'll do it asap. (as soon as possible, which will mean monday or tuesday; at least its a nice idea and nice that someone works on this

) )

cu

Fabian

**Fabianx** · 07-26-2003, 12:58 PM

Originally Posted by Lex

the same errorrs on the real PC

It seems like mount does not want to create a RamDisk

Here is a new diff:

Code:

--- linuxrc.orig        2003-07-26 13:10:09.000000000 +0200
+++ linuxrc     2003-07-26 13:48:21.000000000 +0200
@@ -235,7 +235,31 @@
 insmod -f /modules/cloop.o file=/cdrom/KNOPPIX/KNOPPIX
 mountit /dev/cloop /KNOPPIX "-o ro" || FOUND_KNOPPIX=""
 fi
-
+
+ COPYTORAM="yes" # yes we want to copy it
+
+ # CopyToRam ?
+if  test -n "$COPYTORAM";
+then
+  # Pre-test if everything succeeded.
+  if test -n "$FOUND_KNOPPIX"
+  then
+    # copy library cache
+    cat /KNOPPIX/etc/ld.so.cache > /etc/ld.so.cache
+    echo ""
+
+    echo "Copying /cdrom to RamDisk, this will take a while ..." # Hey, we could use some fancy dialog skript here :-))
+    /bin/mkdir /cdrom2
+    /bin/mount -t tmpfs -o size=800M /dev/shm /cdrom2
+    /bin/cp -a /cdrom/* /cdrom2 # Copy everything to /cdrom2; yes we need more things then only the KNOPPIX image, we don't want to produce problems we hadn't before, do we ?
+    umount /KNOPPIX # unmount it
+    rmmod cloop # release CD
+    umount /cdrom  # unmount CD
+    insmod -f /modules/cloop.o file=/cdrom2/KNOPPIX/KNOPPIX
+    mountit /dev/cloop /KNOPPIX "-o ro" || FOUND_KNOPPIX="" # if everything else did suceeded so far, this will hopefully succeed too
+  fi
+fi
+
 # Final test if everything succeeded.
 if test -n "$FOUND_KNOPPIX"
 then
@@ -257,6 +281,13 @@
 # From here, we should have all essential commands available.
 hash -r

+# Did we copy from ram ?
+if  test -n "$COPYTORAM";
+then
+  rmdir /cdrom
+  ln -s /cdrom /cdrom2 # make a symlink and go on to normal boot
+fi
+
 # Clean up /
 rm -rf /modules /static

I also uploaded necessary files and an boot.img for 06-06 and earlier (I know its deprecated, but I don't have newer version atm) to:

http://debian.tu-bs.de/knoppix/RamPatch/

You can get linuxrc also form there.

I tested everything except the copying, as I don't have that much RAM.

cu

Fabian

PS: I'm awaiting your results. VMWare test is fine

[/code]

**Lex** · 07-26-2003, 02:21 PM

I have just tested the modified Knoppix on a 1GB-RAM-PC and it works perfectly (really fast and silent, too).

Great job, Fabian!

EDIT: you may have to use the "toram" cheat code if you have used the boot.img for modifying Knoppix

**ahfoo** · 07-28-2003, 02:38 PM

I didn't see that anywhere? Might there be a shortcut to a pure RAMDisk based install with this magic cheat code? That would sure be nice. 750 megs of RAM is pretty easy to come up with these days.