[Help] Write on poor man's install?

[victoria]

Hi, I have a poor man's install (compressed on HDD, just like the livecd) with grub bootloader instead of isolinux.
Is there a way to modify and permanently save the grub.lst while I'm running my knoppix system?
The location seen from another system where I hooked My HDD is /media/hdd1/boot/grub/grub.lst. When I'm running from my knoppix HDD, It will be /cdrom/boot/grub/grub.lst but because the system is read-only, I can't save on it. How could I make r/w temporarly that location?
Any help much apreciated.
V.

[ockham23]

Do you mean "menu.lst"? What do you want to achieve? Edit grub boot menu and/or add cheat codes to default kernel options?

[victoria]

Do you mean "menu.lst"?

Yes that's it, my bad...

What do you want to achieve? Edit grub boot menu and/or add cheat codes to default kernel options?

Something like that, but a more general goal is to be able to save files in that area. Let say, beside boot directory to create my own directory where to be able to permanently save files.
I don't know if I can/how remount that portion of "CD" as read/write.

[ockham23]

You can customize Knoppix by creating a persistent home directory on your hard drive and even modify the cd image file with unionfs by storing your modifications in a special unionrw directory on your hard drive.

Editing menu.lst, however, isn't that simple if grub itself and menu list are located inside the image file. You would have to copy the files from the cd to a temporary directory, edit menu.lst according to your needs, and create a new iso file from the copied files with mkisofs.

[victoria]

You can customize Knoppix by creating a persistent home directory on your hard drive ... [snip]

Can be instead of persistent home directory just another generic directory? I could use some links to point in that direction and use it to store whatever I need... Would it be writeable out of UNIONFS?
Thanks, V.

[ockham23]

I just reread your initial post. Apparently, menu.lst is located in a folder that is not part of the image file. So you should be able to edit to contents of the file if you boot off the Knoppix cd instead off the image file.

And, yes, you can store your data in any directory on your computer's hard drive or on any removable drive unless the file system of the drive is NTFS. File systems with write support are - among others - FAT32, FAT16, ext2, ext3 and reiserfs. Before you can write to the drive you have to tell Knoppix to mount the drive. In this regard, a persistent home directory is more convenient because it is mounted automatically when Knoppix starts.

Unionfs is not required if you only want to store user data to permanent folder on a hard drive or a removable drive. However, you cannot add new programs to Knoppix without using unionfs.

[victoria]

I just reread your initial post. Apparently, menu.lst is located in a folder that is not part of the image file. So you should be able to edit to contents of the file if you boot off the Knoppix cd instead off the image file.

And, yes, you can store your data in any directory on your computer's hard drive or on any removable drive unless the file system of the drive is NTFS. File systems with write support are - among others - FAT32, FAT16, ext2, ext3 and reiserfs. Before you can write to the drive you have to tell Knoppix to mount the drive. In this regard, a persistent home directory is more convenient because it is mounted automatically when Knoppix starts.

Unionfs is not required if you only want to store user data to permanent folder on a hard drive or a removable drive. However, you cannot add new programs to Knoppix without using unionfs.

Thanks for the answers, I think I need to re-state what I'd like to accomplish:

- without any external help (knoppix CD, or other linux), just within my knoppix-like HDD install...
- without any other partition/disk intended for storage...

... just the same way I have the "boot" directory, I whish to have another writeable directory used just for read-write-save files. The purpose is to use this install on a compact flash, without abusing the write cycles which would compromise the CF. I won't mind to make/run a script to "remount -rw" or "remount -ro" this directory.
Having for this purpose another partition seems logic and trivial. But I wonder if I just could use the same partition for this, even the way of doing it is not trivial. In the end, I could protect under the "ro umbrela" also my "special directory"

[ockham23]

Having for this purpose another partition seems logic and trivial.

Well, there's your answer.

[Jacky]

If I understand correctly, you want to mount r/w the partition where your iso image is.

When you boot from a iso image on disk (as in your poor man's install), the partition where the iso is will be mounted as a cdrom loop device in read-only mode. For example, if the iso file was on hdd1, then mount will read "hdd1 on cdrom2.loop type ext3 (ro)".

To make hdd1 writable, issue the following mount command:

mount /dev/hdd1 /cdrom2.loop -o remount

Regards.

[victoria]

To make hdd1 writable, issue the following mount command:

mount /dev/hdd1 /cdrom2.loop -o remount

Works like a charm!
Thanks to all for their suggestions.
Have a great day, V.