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PostPosted: Mon Nov 05, 2007 10:09 am 
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Joined: Mon Nov 05, 2007 9:46 am
Posts: 2
Hi everybody, new to this forum ; while I'm experienced in Linux (esp. SuSE and Ubuntu) or Solaris, I don't know yet the KBP architecture.

I did not change the OS of my KBP (to Debian) yet, since some questions are haunting me :) Sorry if they sound too basic, I'm a KBP-Linux starter...

- Is the Debian release at least as reliable as the original one? [I still need to run the KBP as a backup server :)
- can we observe performance improvement/loss with Debian?
- Is Debian able to recognize and run all the devices (USB, Leds, sound, interfaces...)
- Is it possible to install Debian on the Flash NAND, mounting the Flash and run the OS from it so that it does not take RAM ; and have all "writable" part mounted on disk (/tmp, /proc...). Is it too slow?
- Is backing up the original Flash (with 'dd'?) on a separate partition of the disk (eg 1 GB) a good idea?
- Is Debian the recommended update?

Dev questions

- I understand the processor is specific: how is the original compiler compared to the Debian one? No compabilities issues?
- Usually, to recompile an existing Linux module (say, for Ubuntu) on KBP, provided that the Libs are available, is rather an easy task? (of course something not requiring a X server for instance...)

Hard question

- Did anybody try to remove the 128 MB RAM chip (with a soldering iron) and replace with a 256 MB (of same family)?
- Is it possible to boot from an USB Flash module attached?

That's all for now, thanks.

chabadam


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PostPosted: Tue Nov 06, 2007 4:49 am 
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Joined: Mon May 30, 2005 9:01 am
Posts: 279
Location: France, St Cyr-L'Ecole (78)
Well that's a big list of questions ...
I'll try to answer fast :
- Debian is very stable, don't worry about that
- You can have a little loss of performances on some specific stuff using encryption : The versions of OpenSSL/OpenSSH in the stock kernel have been modified to use some hardware features of the CPU. But don't worry, it'll not be really a problem as cryptographic library is not used that much on a NAS ... Other things will run almost the same way.
- Debian as nothing to do with devices ! It's the Linux Kernel that will do that ! What can be installed then are tools to use the detected devices (like a MP3 player for a sound card ...)
- Things seems not clear for you about RAM/OS and Filesystem !
*The OS is Linux, It can't be run directly from a NAND flash, it have to be loaded in RAM and run from there (There are solutions to run a kernel from a NOR flash, but it can't be done on a kurobox Pro)
*The filesystem is Debian, it stores all the scripts, configuration and applications/lybraries. It can be stored in Flash, but each time an application will be used, it will be loaded in memory (exactly like when the filesystem is stored on a HDD). You can't reduce RAM usage that way
*RAM is the place where things are loaded while "active". Do a "ps aux" in linux to see what is active in memory and you'll understant what I mean. If things are loaded from a NAND flash or a HDD will make almost no difference (maybe one will be faster to be loaded from than the other ...)
- using dd to work with NAND flash is not the best thing to do (due to the way a NAND flash is working). Please use nanddump & nandwrite from the mtd-tools package. If you want to know more about NAND flash, please read this paper
- I don't understand the question debian beeing the recommended update ...


PostPosted: Mon Nov 05, 2007 5:09 pm Post subject: Kurobox Pro / Debian questions
Hi everybody, new to this forum ; while I'm experienced in Linux (esp. SuSE and Ubuntu) or Solaris, I don't know yet the KBP architecture.

I did not change the OS of my KBP (to Debian) yet, since some questions are haunting me Smile Sorry if they sound too basic, I'm a KBP-Linux starter...

- Is the Debian release at least as reliable as the original one? [I still need to run the KBP as a backup server Smile
- can we observe performance improvement/loss with Debian?
- Is Debian able to recognize and run all the devices (USB, Leds, sound, interfaces...)
- Is it possible to install Debian on the Flash NAND, mounting the Flash and run the OS from it so that it does not take RAM ; and have all "writable" part mounted on disk (/tmp, /proc...). Is it too slow?
- Is backing up the original Flash (with 'dd'?) on a separate partition of the disk (eg 1 GB) a good idea?
- Is Debian the recommended update?

Dev questions
- Debian compiler is that same than the "original" compiler ... It's just GCC ...
- Compiling an additional module is possible...

Hard questions
- Nobody changed the RAM chip from what I know ...
- Good question, I don't know the answer for sure

Sylver


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PostPosted: Tue Nov 06, 2007 7:18 pm 
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Joined: Mon Nov 05, 2007 9:46 am
Posts: 2
Sylver wrote:
Well that's a big list of questions ...
*The OS is Linux, It can't be run directly from a NAND flash, it have to be loaded in RAM and run from there (There are solutions to run a kernel from a NOR flash, but it can't be done on a kurobox Pro)
*The filesystem is Debian, it stores all the scripts, configuration and applications/lybraries. It can be stored in Flash, but each time an application will be used, it will be loaded in memory (exactly like when the filesystem is stored on a HDD). You can't reduce RAM usage that way
*RAM is the place where things are loaded while "active". Do a "ps aux" in linux to see what is active in memory and you'll understant what I mean.

- I don't understand the question debian beeing the recommended update ...

Hi Sylver,

thanks for the answers!

My question about Flash and RAM was probably not clear. Flash is memory. It has a start and end addresses. Usually the CPU runs instructions from the RAM, however it can do it wherever its program counter points to [provided that buses allow that]. So, if one would set the program counter to an address in the Flash addresses range, it should execute the Flash code without pre-loading/copying the code in RAM, and save a lot of it [the same way a processor executes code from a ROM].

Besides, I don't think Debian is the filesystem but is rather the OS. A filesystem is dealing with data-access, like ext3, ntfs, jffs2... Debian may include or no the kernel in its distro (and I think it does) - well, just a vocabulary thing, not important.

"Debian as a recommended update" question: There are several "upgrades" for the Kurobox, one is Debian, others are Gentoo, Fedora, and a one that you know well, Sylver. I wondered which is the most stable, the most useful or the most popular.


Another question that bugs me: what is the difference between kurobox.com and nas-central.com ; are they owned by the same persons? Personally I find it easier to post / search data from kurobox.com as it deals with only 1 box family, mine!

Thanks again


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PostPosted: Wed Nov 07, 2007 6:54 am 
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Joined: Mon May 30, 2005 9:01 am
Posts: 279
Location: France, St Cyr-L'Ecole (78)
Chabadam wrote:
Hi Sylver,

thanks for the answers!

My question about Flash and RAM was probably not clear. Flash is memory. It has a start and end addresses. Usually the CPU runs instructions from the RAM, however it can do it wherever its program counter points to [provided that buses allow that]. So, if one would set the program counter to an address in the Flash addresses range, it should execute the Flash code without pre-loading/copying the code in RAM, and save a lot of it [the same way a processor executes code from a ROM].

Besides, I don't think Debian is the filesystem but is rather the OS. A filesystem is dealing with data-access, like ext3, ntfs, jffs2... Debian may include or no the kernel in its distro (and I think it does) - well, just a vocabulary thing, not important.

"Debian as a recommended update" question: There are several "upgrades" for the Kurobox, one is Debian, others are Gentoo, Fedora, and a one that you know well, Sylver. I wondered which is the most stable, the most useful or the most popular.


Another question that bugs me: what is the difference between kurobox.com and nas-central.com ; are they owned by the same persons? Personally I find it easier to post / search data from kurobox.com as it deals with only 1 box family, mine!

Thanks again


Well, actually, what you say about flash beeing almost the same than RAM (beside the way to write in it) is true but for NOR flash memory. A NAND flash memory is not working the same way at all (because NAND memory have bad blocks, ECC to correct errors ...). Because of the data not beeing continious (maybe because of a bad block, or for any other reason), you can't just set your PC to the address of the code to run and expect it to work. In few words : the NAND flash have not been designed to be something you can run code on (it's very close to the way a hard drive works!). If you want to learn more about NAND flash, you should really read the document I talked about in my first message !

Debian is a kernel + all the other things that makes the system runs, so you're right, Debian is an OS. Anyway the Debian stuff (besides the kernel) have to be in the root file system (by telling file system I means root file system), and the kernel may be also in the root file system (but it can also be stored in a NOR or a NAND flash, and even in an EEPROM or whatever storage that can be handled by the bootloader, as it will just be stored in RAM an it will run from the RAM !). Anyway it's not really important ;)

So, by upgrade, you mean "is debian the recommended OS ( :wink: ) to run on the kurobox ?". This question is not easy to answer. The worst choice is for sure the 'sylver image' (it was an attempt to keep the original OS with its administration interface, but it's too hard to maintain in line with lastest code versions). Debian, Gentoo or Fedora Core is just a question of taste ... I really can't say which one you'll prefer, all I can say is that I'm using the Debian one and I'm really happy with it ! But I'm pretty sure that you'll also be happy with Gentoo or Fedora !

And for the last question, kurobox.com & nas-central are not the same thing, but as both communities are doing almost the same things (and most important members are member of both communities), it have been decided to merge the communities (actually kurobox.com & linkstationwiki.org are beeing merged in nas-central.org). The merging is still in progress (the wiki have been merged already and the forum is beeing merged), but be aware that this situation will stop one day ;)

Sylver


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