HowTo: Switch to Linux to finish factoring

[Batalov]

Retry it on a completely idle computer (maybe try to kill as many useless processes in your Task Manager, sorted by size, beforehand).

You can also do the Ubuntu installation. Not just for this, but for the future experiments (as well as fast sieving). Ubuntu will see the existing drives - you will not need to transfer data.

You are almost there.

[Andi47]

Originally Posted by Batalov

Retry it on a completely idle computer (maybe try to kill as many useless processes in your Task Manager, sorted by size, beforehand).

You can also do the Ubuntu installation. Not just for this, but for the future experiments (as well as fast sieving). Ubuntu will see the existing drives - you will not need to transfer data.

You are almost there.

I did the filtering step (-nc1) with msieve 1.38 overnight and attempted the matrix step (-nc2) with 1.42 - it failed to allocate 35 MB.

Now - as I see your answer - I installed a pending windows update and rebooted, and then killed every process which I dared to kill. Now, I am retrying with ~50MB more free RAM. (Unfortunately I can't completely deactivate my virus scan (the laptop I'm doing the matrix on is currently disconnected from internet), I hope that it doesn't kick in and shoot the matrix process down by using one MB too many.)

When it fails again, I guess that I'll have to either do some more oversieving (and hope to get a smaller matrix), or to install Ubuntu.

Ubuntu questions:
- Is there a possibility to boot Ubuntu from a CD or an USB stick?
- if not: How do I set up my laptop as dual boot system? (currently, WinXP is installed; I don't want to uninstall it - or anything else)
- Even if Ubuntu sees all existing drives - I guess I will have to compile msieve for Linux? (Is there a howtodo out there for linux noobs?)

[axn]

Originally Posted by Andi47

Ubuntu questions:
- Is there a possibility to boot Ubuntu from a CD or an USB stick?
- if not: How do I set up my laptop as dual boot system? (currently, WinXP is installed; I don't want to uninstall it - or anything else)
- Even if Ubuntu sees all existing drives - I guess I will have to compile msieve for Linux? (Is there a howtodo out there for linux noobs?)

Having recently gone thru the process, let me try to answer:

1. Yes.
2. Download ubuntu .iso, and burn the CD. use it to boot. It will guide you. It will show which hdd has space and stuff. Just allocate a reasonable size partition, and the installer will automatically take care of creating the dual boot.
3. you need to first make sure that gmp is installed. i don't remember whether it is installed by default or not (if not, use Synaptic Package Manager to do it). other than that, compiling is as easy as downloading msieve source and doing a "make x86_64" command.

[henryzz]

if you need help compiling msieve people on the forum can help

[Andi47]

Originally Posted by axn

Just allocate a reasonable size partition...

Does this mean that it will automally generate the partition when I allocate - say - 10 GB? (would 10 GB be enough? Can I install Ubuntu on a "minimal sized" partition and then install other programs (to run under linux) in a seperate folder on the windows partition? How many GB would be "minimal sized"?)

My laptop currently has only got a C: drive (currently ~32 GB free) which I would have to divide into two partitions.

[xilman]

Originally Posted by Andi47

After a filtering attempt (51M raw rels, 44.2M unique), I got this:

...
Mon Sep 14 21:28:56 2009  commencing cycle optimization
failed to reallocate 163840000 bytes

*grrrr*

I will retry -nc1 with 1.38 and see if it swaps or aborts. If it aborts, I'll try filtering on my (a bit slower) P4 (3 GB RAM available) - or is there a trick to force msieve 1.42 to use swap instead of aborting with with "failed to reallocate xy bytes"?

The critical word in that message is "reallocate".

I ran into this problem many times when performing large factorizations on 32-bit MS Windows machines. It's not (usually) lack of memory that causes the crash, it's virtual address fragmentation. Sundry system components are located at fixed virtual addresses. Even if there is enough physical memory to reallocated your data somewhere else, there isn't enough contiguous unused virtual address space to hold the two copies, old and new, while the reallocation takes place.

The only solutions I know of are to run 64-bit Windows or to run a Unix-like operating system, preferably on a 64-bit machine.

In your case, I'd definitely recommend running a 64-bit Linux from a live CD with user data held on a USB stick so you can recover from system outages.


Paul

[axn]

Originally Posted by Andi47

Does this mean that it will automally generate the partition when I allocate - say - 10 GB?

Yep. Windows will not see the linux partition, but linux can see the windows stuff. 10GB is pretty reasonable for linux install.

[Andi47]

Thanks for advice. I am downloading ubuntu now and will install next weekend. As long, I will sieve for 1 additional MQ and try filtering again. (if this one turns out to run happily on windows, I will postpone the installation of ubuntu until the matrix has finished.)

[Andi47]

Originally Posted by Andi47

Does this mean that it will automally generate the partition when I allocate - say - 10 GB? (would 10 GB be enough? Can I install Ubuntu on a "minimal sized" partition and then install other programs (to run under linux) in a seperate folder on the windows partition? How many GB would be "minimal sized"?)

My laptop currently has only got a C: drive (currently ~32 GB free) which I would have to divide into two partitions.

AAAAAAAaaaaaaaaarrrrrrrgggghhh!!!

Ubuntu insisted in setting a password when installing, and - after 5375641467 retrys to login - I think that I must have either misspelled the username, or misspelled the initial passwort twice when installing it, with the result, that I can't login to ubuntu now.

I guess, I will have to kill the installation and retry - how do I do that? Just boot into windows (this still works), format the ubuntu partition and start installation again, or do I have to do more?

[axn]

Originally Posted by Andi47

AAAAAAAaaaaaaaaarrrrrrrgggghhh!!!

Ubuntu insisted in setting a password when installing, and - after 5375641467 retrys to login - I think that I must have either misspelled the username, or misspelled the initial passwort twice when installing it, with the result, that I can't login to ubuntu now.

I guess, I will have to kill the installation and retry - how do I do that? Just boot into windows (this still works), format the ubuntu partition and start installation again, or do I have to do more?

Try this link: http://www.psychocats.net/ubuntu/resetpassword. Print/write out the instructions, before you attempt it (or use a second computer).

[Andi47]

Originally Posted by axn

Try this link: http://www.psychocats.net/ubuntu/resetpassword. Print/write out the instructions, before you attempt it (or use a second computer).

THANKS, this worked. The key was ls /home which showed me, that my username had been set to be every letters lowercase, while I always typed the first letter uppercase.

Edit: Seems I'm really a total linux noob.

Questions:

1.) Is it really possible to see the windows partition? How?
2.) How do I open a prompt window?
3.) How do I install GMP?