How to boot with saved session, but read-only?

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jden
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Joined: Sun 21 Apr 2013, 11:15

How to boot with saved session, but read-only?

#1 Post by jden »

Hello -

first time here - sorry if this has been addressed elsewhere (I've looked in lots of threads, haven't had any joy).

I've been trying to figure out how to make a USB-bootable full puppy installation that remains completely unchanged between sessions. I'm failing.

I've turned off all session saves as far as i can tell, but even if i just boot (from USB), then immediately pull out the USB disk and check the MD5 hashes on the USB disk (in another OS) the hash of the save.2fs file always changes (no other files change, though the fsckme flag file is there when i do this). If i mount the save.2fs in another puppy I can see modified files, modified at the time of boot.

I thought puppy booting would be essentially just read-only, and wasn't supposed to modify anything (until you choose to save your session later). Am I misunderstanding?


To explain what i'm trying to do: on my very first boot I want to be able to set various things (firewall, wifi, some theme & firefox prefs etc) - and then use this exact session every time I use puppy*. I want to be able to check MD5 hashes every so often, just to be sure, but the fact that the save file changes even when I apparently do nothing means this doesn't seem possible.

* ie don't want to just use pfix=ram or similar...

Any help anyone can give will definitely be appreciated.

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Flash
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#2 Post by Flash »

I think this same basic question was discussed in a recent thread.

What filesystem did you format the USB drive with before you installed Puppy in it?

I guess you could remaster a Puppy before you install it. Theoretically you wouldn't need a Save file at all, since the changes and settings should be incorporated into the remastered Puppy.

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dennis-slacko531
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#3 Post by dennis-slacko531 »

May I ask, are you saying you need a pristine Save File? That's the way I read your question.

you said,
I want to be able to check MD5 hashes every so often, just to be sure, but the fact that the save file changes even when I apparently do nothing means this doesn't seem possible.

My reply,
Are you trying to build an "anonymous" kind browsing situation for possible business, etc?
I'm probably missing your need, but good luck. :lol:

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rcrsn51
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#4 Post by rcrsn51 »

Your savefile is mounted R-W. So even if you don't explicitly write back to it, there could be slight changes.

Read here for a method that always starts with exactly the same savefile.

[Edit] However, I have never tested this with a USB install.

[Edit-Edit] Here is a version that works for me with a FAT32 flash drive:

Code: Select all

sleep 3
mount -t vfat /dev/sdb1 /mnt/data
cp /mnt/data/slackosave.bak /mnt/data/slackosave.3fs
umount /mnt/data

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Flash
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#5 Post by Flash »

This is the thread I was thinking of.

jden
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Joined: Sun 21 Apr 2013, 11:15

#6 Post by jden »

Hi - thanks for your replies.

I'll be tinkering again this weekend, so I'll have a chance to look through the linked threads then - and will attempt some of your suggestions.


But in response to some of the questions so far -

Flash - the USB stick was FAT32 formatted. I hadn't tried to remaster - that might be exactly what I'm looking for.

dennis-slacko531 - I suppose I'm saying that I want my save file to be set once (at first boot), and then I want that file to remain completely unchanged from that point on.... (so much so that I can check its md5 hash every so often).

I'm not really trying to build anything for anonymous browsing - I'm just a bit paranoid about banking online and stuff - so i like the idea of using a puppy build that is freshly downloaded, changed once with my prefs and then remains - verifiably - completely the same from that point on.

This is probably just ignorance on my part (about linux in general) driving my paranoia. I obviously start from the POV that i trust using puppy in the first place. It's just subsequent changes that I want to feel secure about (by preventing them!)

rcrsn51 - indeed there are changes even though I've (as far as I can tell) switched off all periodic (and final) saves. Mounting the save file in linux mint showed a small number of files with new modified dates (modified at the time of the last puppy boot). But i'll maybe have a try with the code you sent.


Again, thanks all.

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