Puppy Linux Discussion Forum

Perkins · Joined: 25 Sep 2005 Posts: 62

I'm running a multisession live DVD on an older machine, and have run into an irritating issue. I started with 4.00, and went to 4.1 to see if this problem was fixed, but no luck.

This machine has 512MB of memory. This turns into about 200MB on the free memory indicator. This amount stays pretty well constant since most of what the machine does is web browsing. It fluctuates about four meg depending on the state of the browser cache.

However, as the saved sessions stack up, I am starting to get "RAM FULL" messages as it is loading folders from the disk on startup. If I save any large files, the message appears earlier in the process. If I delete them, it moves back down the list. Regardless, when the boot completes, I have 200MB of memory on the indicator. My guess would be that as it's loading files it's still loading old copies for some reason, even though it subsequently crunches it all down to a smaller size.

Plugging in a USB drive formatted as linux-swap increases the free space on the indicator, but has no effect whatsoever on how far it gets through the loading process before the ram fills up.

This is turning into a rather ugly problem since as the disk fills up it's failing to load configuration settings and such. Any tips on how to fix it would be appreciated.

mikeb · Joined: 23 Nov 2006 Posts: 8028

Hmm your assessment sounds about right which results in more memory space is needed during boot than once fully running.

Suggestions

1) only save when you need to...the browser for example creates a large amount of fresh files everytime it runs which subsequently get saved and loaded again.

2)If you have decent internet speed set browser cache to 0...plus do you use email?..can you use imap in that case?

3) there is/was an /archive folder...the purpose was that any files put in here would be saved to the cd but not loaded into ram...ie still accessible through the mounted cd....good place for large data files.

regards

mike

HairyWill · Joined: 26 May 2006 Posts: 2949 Location: Southampton, UK

It may be that there is a bug in init that doesn't include the swap space in its ram calculations.

I suppose I ought to look at the code before making this suggestion, but I don't have time right now and want to get it written down.

trapster · Joined: 28 Nov 2005 Posts: 1999 Location: Maine, USA

mikeb · Joined: 23 Nov 2006 Posts: 8028

I forgot to ask which puppy version.....was something i noticed on 2.02...been a while since I multisessioned.

mike

alienjeff · Joined: 08 Jul 2006 Posts: 2291 Location: Winsted, CT - USA

Do you have a swap partition set up on a integral (not USB) hard drive? If so, what size?

I'll be curious to see what Flash has to say about this one. He's our resident Multisession Advocate.

Perkins · Joined: 25 Sep 2005 Posts: 62

Nope, no swap on an internal disk. It was a temporary solution for my mother's XP machine when it died. I have since rebuilt it. (It's still XP since she uses programs that defy my attempts to make run or find substitutes for on Linux.)

I tried both 3.something and 4.something, both exhibited the same problems.

I suppose the thing to do would be to make it check the size of the data on the disk and size the initial ramdisk appropriately. I'm not facile with Puppy's internal workings, so I'm not sure if that's possible. True, it might slow it down, but booting from a multisession disk isn't exactly fast anyway...

One could put the initial size into a file, and then only recalculate if it gets filled up... Not sure how difficult that would be.

alienjeff · Joined: 08 Jul 2006 Posts: 2291 Location: Winsted, CT - USA

Put a swap partition on the HD and you should enjoy a more pleasant experience.

Perkins · Joined: 25 Sep 2005 Posts: 62

Well, I'll keep that in mind. I usually end up using the multisession option though when I don't want to mess with the harddrive.

Béèm · Posted: Fri 07 Nov 2008, 15:58 Post_subject:

Perkins, I suppose you have knowledge of this document?

Perkins · Joined: 25 Sep 2005 Posts: 62

Yes, I've read it before. I just went through it again, and it kind of confirms my guess about what was happening. I'm thinking the pup_ro1 ramdisk is too small to hold all the saved files, so it skips some, and then when the pup_rw is created and layered on top of it it gives the same 200MB of free space. Meaning that I have 200MB of working space once the computer is up and running, but not necessarily that amount of permanent storage.

Does that seem to be a correct analysis? Or is there some other reason why I'd have a fairly constant amount of free space, but fail to load files at startup? I'm not terribly good at bash, so reading the startup script myself to see what's happening kind of makes my brain try to melt.

Flash · Posted: Fri 07 Nov 2008, 23:23 Post_subject:

Here is a way to "defragment" a multisession DVD that might help.

Assuming you can get your multisession Puppy DVD booted up, use Burniso2cd to burn a new DVD with the same iso (or a newer one, if you want to upgrade) then shut down leaving the newly burned DVD in the drive you booted from. Choosing to save when you shut down will transfer everything from the old DVD to the first session of the new DVD. Walla, you have combined all those sessions into one. The next time the new DVD boots, it will not have to load all the intermediate sessions that caused you trouble on the old DVD. This trick works particularly well with a DVD+RW; Burniso2cd will overwrite whatever is on a DVD+RW without having to blank it first. Of course, if you are using multisession Puppy for forensic reasons, you would start a new DVD+R instead of using a rewritable DVD.

Incidentally, have you noticed that when multisession Puppy boots up, the sessions are loaded starting with the last one saved on the DVD and working to the first? I don't understand how that works, but it obviously does.

Perkins · Joined: 25 Sep 2005 Posts: 62

The time I tried moving to a new disc, it actually made the problem worse. I suppose I should clarify a bit with the results of some of the experimenting I did once I no longer needed the system to work.

The amount of data on the disc seems to actually be fine. It all fits into memory on bootup. However, if I add more than one or two MB to it, it bumps the last couple of sessions. If I then delete the extra data it will go back to working properly. So somehow I'm right on the edge of how much space it has on bootup. If I make a new disc with it over the size limit, then it has one big set of files it fails to load instead of a couple of little ones. So it's ok for the first session, but after that the whole thing craps out and dies.

The sessions, Flash, are loaded in reverse order because it's more efficient that way. You load the newest copy of any file first, and can then skip all the older copies. If you did it the other way, you'd have to overwrite all the old copies with newer ones until you get to the newest set, and then delete any files that were deleted. More complicated, and would take much more time since you would essentially have to read *all* the data on the disc instead of skipping anything which has already been superseded.

Flash · Posted: Sat 08 Nov 2008, 12:02 Post_subject:

Perkins · Joined: 25 Sep 2005 Posts: 62

Except that you don't have to read all the data. Just the file names. If it doesn't exist already, and there's no deletion marker, then you copy it. Otherwise you don't. Basically it's a "cp -u" (copy only if destination is older than source or does not exist), and since you're going last to first, whatever you have at the end is the latest version. First to last you can't skip any data at all, unless you read all the filenames and then decide which ones to copy, which would be needlessly complicated.