[Ubuntu-be] Remember - IRC meeting tomorrow Thursday 28/10/2010 at 21.00 hr.

Fri Oct 29 18:23:45 BST 2010

Jan,

You're welcome.

But I do also agree with what Steven says: for a user it's the user
experience that counts (although the technical background will explain why
some things happen one way or the other, but even with such background it
can be very hard to predict the performance difference between two totally
different systems: for some things Windows might work better, for other
things Linux might work faster). In general it's rather hard to say that one
or the other is really better; both have their quirks so it comes down to
personal choice to decide which one suits you best for a particular purpose
(e.g. Linux has games but it's not easy to play any Windows game in Linux).
The most important part of the user experience is the installation of
applications (or rather the applications itself): if you know a lot of
applications or know how to find them, you can easily give the students good
directions to get some kind of work done (e.g. if they want to play a first
person shooter, you can point towards Warsow; BasKet for note taking, ...).
As you will know as an educator: people will be more interested in things
they can relate to and most people only want a computer to work (they don't
care what each electron in the internal circuits does).

For your presentation I think it's fairly important you also include some
eye candy as for young people it's mostly about appearance. Compiz is a
great way to "show off", some rotations of the cube (or usage of the scale
(like Exposé on Mac), group, (enhanced) zoom desktop, shift/ring switcher,
... plugins) here and there might keep them interested. Although some people
find Compiz only eye-candy, I can't hardly live without it because it
provides an easy interface to customize your whole desktop experience
(shortcuts, screen corner actions, ...) and it allows me to have a really
productive environment. (If you want something similar for Windows, you can
give Dexpot a try, it doesn't come close but it's better than nothing).

For the record: contrary to what I said; some malware does exist for Linux
(and Mac and Windows for that matter), but it's very new. The security bug
is/was caused by Java, so it's more or less OS independent if you have an
old version of Java installed. More
info<http://news.softpedia.com/news/New-Koobface-Variant-Infects-Linux-too-163450.shtml>.
As the article says, the worm can't survive a system reboot on Linux (in my
eyes that only means that the cracker who wrote that PoS has very little
experience with Linux and how to make it start automatically; but reading
between the lines I suppose that also means that the worm can't get hold of
real admin privileges). A lot of people used to say that as Linux (and Mac)
would gain market share, more and more malware would become available for
these systems. Others used to say that large scale malware would never
really bother Linux. I used to take the middle ground most of the time
(Linux has a better security layer IMHO, but on the other hand: software
without bugs does not exist), but this event points out that it more or less
comes down to the fact that a lot of crackers and script kiddies are not
familiar at all with Linux. In any case: any security expert will confirm
that in most cases the computer user is the weakest link, so if your system
enforces good rules, that will help a lot (e.g. if you don't allow empty
passwords, don't provide a standard password for root, don't grant admin
powers to everyone, ...).

Kind regards

Egon

On Fri, Oct 29, 2010 at 18:17, Jan Bongaerts <jbongaerts at gmail.com> wrote:

> Egon,
> thank you VERY much for taking the time to write such a comprehensive
> answer.
> It does help a lot, and clarifies a lot of issues I didn't understand
> before.
> Thanks for such an educational insight. As a flight instructor, I know how
> difficult is to bring a technical subject across to laymen.
> You are doing this very well and I commend you for it.
> Cheers,
> Jan.
>
>
> On Thu, Oct 28, 2010 at 4:45 PM, Egon Geerardyn <egon.geerardyn at gmail.com>wrote:
>
>> Dear Jan,
>>
>> To answer your questions:
>>
>> a) the memory requirements of Linux vary a lot with what programs you use
>> (and what for), but a basic Linux desktop (e.g. writing letters, some small
>> spreadsheets, some e-mail, some photo's and some web browsing) is perfectly
>> feasible with the amount of RAM you mention. Regarding regular Ubuntu, I
>> haven't tried a really low-end setup (I did check with 512 MiB RAM and
>> fairly decent Mobile Pentium 4 and quite low-end Mobile Celeron (P4
>> generation)). Works really well for most people; but don't expect it to beat
>> any new equipment. In any case: some variant of Ubuntu (e.g. Xubuntu or
>> Lubuntu) have lower requirements than Ubuntu or will perform better on older
>> hardware. This is because they have "less" features (they are just more
>> optimized towards memory and processor usage). On the other hand, Linux can
>> be tailored to fit your needs (add this, remove that, ...) while in Windows
>> only very few people bother to slim down their installation.
>>
>> Overall Linux has better memory management algorithms which the user can
>> tweak a little. For most Windows folk, the effeciency of an algorithm is
>> measured by how much free memory you have.  That actually is a very bad
>> measure, as the amount of free (or unused) memory does not really contribute
>> to the performance. Not having any free memory does slow your computer
>> terribly, but as long as you have a bit of free memory it should work fine.
>> In layman's terms, the free memory is head room.
>>
>> During the Windows XP era, the comparison between Linux and Windows was
>> fairly simple: the Windows memory management was prehistoric. Very little
>> caching (that's a mechanism to make a computer faster) and swapping even if
>> the computer doesn't need it. With Windows Vista, the algorithms used were
>> really improved a lot: Vista caches a lot more data, which should make it
>> faster. Windows 7 has improved little, only the overall performance of the
>> system was improved, since Vista was really a resource hog.
>>
>> In less technical terms (for your pupils): suppose you are making your
>> homework (data) on your desk (RAM space). Then you have two general
>> approaches. Some people (i.e. Linux) will get the assignment and directly
>> after that they will think about what they might also need so they go to the
>> closet in the other room and take  (cache) their pens, some text books, a
>> dictionary, a calculator, writing paper, ... out of the closet if it's not
>> already on the desk. So they have most of the things they need at hand and
>> they start to work. Other people (i.e. Windows XP) will take the assignment
>> and sit down to think about the assignment and they don't understand a word
>> in the text. They fetch the dictionary in the other room, return with the
>> dictionary and work on the assignment until they want to write down
>> something so they fetch paper and pens, and so on and so on. The first kind
>> of people might have less space free but will have more at hand to quickly
>> solve their homework; while the other people will have lots of free space on
>> their desk but they will have to run a lot to get other things they need
>> (and will lose a lot of time while their desk is large enough to hold a few
>> extra items). In this case, as Linux and Windows 7/Vista notice that your
>> free space is becoming too small to work comfortably, they will put away the
>> parts of the cache they expect not to use (i.e. remnants from other
>> assignments).
>>
>> A bit more background about memory; the actual need for memory is based on
>> 2 large factors: we want a lot of storage capacity (loads of data (e.g.
>> videos) to process and we want to pay as little as possible. Some memories
>> are quite cheap per storage unit (e.g. hard disks, dvd-r, ...), nowadays it
>> costs next to nothing to store a few gigabytes on a HD; but on the other
>> hand these devices are really slow. On the other hand, electronic memories
>> are really fast, you just store a very small bunch of electrons in a
>> transistor (or next to one); no need for any mechanical parts. But these
>> memories are really expensive to store a lot of data in (the level 1 (L1)
>> cache of your processor is a very nice example). Of course some memories are
>> in between both extremes (e.g. your RAM memory is a lot faster than a hard
>> disk but not as expensive as those really fast memories). To get the
>> positive sides (fast and a large storage for little money) from both
>> extremes, we apply a little trick. When our processor needs a bit of data,
>> it only looks in the L1 cache (the fast one), if we notice that the needed
>> piece of data is not available we try to get it from a slower memory (L2
>> cache) or even a slower memory (L3 cache; RAM memory or finally the hard
>> disk). The piece of data is then copied to all the fast memories such that
>> if we need that same piece of information a little bit later, we can access
>> it really fast (because it will be in the L1 cache). On the other hand, when
>> data goes stale in this fast memory (the fast memory is full, so the
>> computer tries to free up some space for new data), the data is written back
>> to the slower memory. That is the principle of caching.
>>
>> Swapping is more or less the opposite. You know you have a fixed amount of
>> RAM available in your computer, so when you try to use more than this
>> amount, the computer will grind to a halt. It has no more possibilities to
>> store any data; so to circumvent this, most operating systems use a certain
>> file in windows called the page file, in Linux a swap file) or even a whole
>> partition (which is used the most in Linux) to store parts of the memory. So
>> the computer tries to free up memory by writing it to the hard disk; but as
>> I already told you: we have a lot of space on the hard disk, but it is
>> extremely slow. That's why your computer becomes really slow when your RAM
>> is full; your operating system will frantically try to write the memory to
>> the hard disk (which you can actually hear in most cases).
>>
>> Regarding swapping, I've noticed that most Windows system almost always
>> have something in their swap file. With Linux you can tune this behavior
>> (you can tell Linux how hard he has to swap), but the default setting is
>> quite decent. In most cases Linux only mostly swap space if the memory is
>> getting too full, so you always retain full RAM speed. (I have tweaked my
>> settings a bit, I have about 4.5GiB (out of 8) used RAM at the moment, but
>> only 28 MiB  of swap used (less than what the default settings should
>> give)). Windows has another characteristic in my experience: even when your
>> memory is not full, Windows will use a lot of swap space (I expect about
>> 1GiB of swap in my case). So Windows is more agressive to "swap out" (write
>> to disk) your RAM contents while that is not necessary.
>>
>>
>> http://www.codinghorror.com/blog/2006/09/why-does-vista-use-all-my-memory.html
>>
>>
>>
>>
>> b) Defragmenting was something that during the mid-nineties was a really
>> hot topic. This was because of the FAT file system; which was a rather
>> "dumb" file system. I won't go into details (because it has been a few years
>> since I revised the technical side of file systems). Fragmenting is a
>> phenomenon that occurs when you save and delete a lot of files on a
>> partition. Let's say you want to save a certain file on you disk, so you
>> look at your disk and notice that at the end you don't have enough space
>> left to store that file; but in between some older files, you have deleted
>> other files so in total free space you have enough room to fit in the new
>> file. What you do is, you fragment the new file (cut it in pieces) and put
>> it in the free holes you find on your disk. When reading the file from the
>> disk (or overwriting the file with a newer version); between each part of
>> the file, your hard disk will have to look for the next part. With FAT this
>> was rather tedious, so it took a long time, so your computer was slow when
>> your disk got fragmented. The same thing happens when you add content to a
>> file that has other files after it: you will have to write the new content
>> in another chunk of file. With newer file systems (NTFS for Windows, EXTFS
>> for Linux), the designers thougth of ways to lessen these problems. I don't
>> really know about the details there or any comparison between Windows and
>> Linux regarding this issue. A possible strategy is to keep some free space
>> after each file, such that when you append to the file, the data written
>> directly after this file. That is something that was implemented (or should
>> be implemented?) in ext4fs which has quite recently become the standard file
>> system in Ubuntu.
>>
>>
>> http://geekblog.oneandoneis2.org/index.php/2006/08/17/why_doesn_t_linux_need_defragmenting
>> http://www.msversus.org/microsoft-windows-performance.html
>>
>>
>> c) Windows has no real package management so no real packages. An
>> application (OS independent) generally makes use of libraries to provide
>> certain functions (e.g. to draw figures on the screen, to print, ... instead
>> of reinventing the wheel every time). Windows has some standard locations
>> for libraries (e.g. C:\Windows\system32 if I'm not mistaken) to store these
>> common parts for your programs. When a program is distributed, it has to
>> know whether these libraries are already on your computer or not. So if you
>> can't assume that it is there, you will have to either provide the libraries
>> you need with your program/installer (or package if you want to call it that
>> way). If you provide the library you can store it either in the standard
>> location which is shared for all programs or put it in the directory of your
>> program. E.g. if you rely on Microsoft Office 2007 to be installed in your
>> program, the program should check that the office libraries are installed.
>> When you distribute your program, you can either provide MS Office together
>> with your software (which might be a tad expensive) or your installer can
>> say to the user "I don't want to install the software unless you install MS
>> Office" (and then it just closes down). Above this problem, you might get
>> some problems with different versions of the same libraries.
>>
>> Windows can only handle 1 version of a library in the shared location. So
>> suppose you have 2 programs that need a different version of a library, you
>> will have to install that library in the directory of one of the programs.
>> So if you're unsure whether to include a certain DLL, just include it and
>> your program will work. This of course causes that if most programmers work
>> that way, you will end up with a lot of different copies of the same
>> library. When a bug is found in that library it is very tedious to fix all
>> occurances of the library (in most cases, people don't even bother!). This
>> has happened a few years back when something was wrong in some graphical
>> library in Windows. A lot of programs had to be fixed one by one because of
>> this.
>>
>> In most Linux distributions you have a package management system (dpkg for
>> Ubuntu with DEB-packages and user interfaces aptitude, apt-get, synaptic,
>> ...). That defines a set of rules to represent both the files of a program,
>> its dependencies towards libraries or other programs and install/uninstall
>> procedures. So when your program needs some library, it is easy to specify
>> what library you want and even what version is good to be used. There is
>> little extra effort for the programmer to specify all of this (because it is
>> standard for the distribution (and in most cases also for some closely
>> related distributions (e.g. Ubuntu uses the Debian system, hence
>> .DEB-files)). Linux can also handle multiple versions of libraries quite
>> well.
>>
>> The need for different versions of libraries is that newer libraries may
>> add or remove features that older software depends on. It is generally
>> discouraged to remove features from a library, but in some cases it has to
>> be done.
>>
>> To summarize: Ubuntu offers one streamlined way to manage your installed
>> programs so program's don't have to include the same file every time and
>> there is a clean way to check everything. More so: package management will
>> even notice if two programs try to overwrite the same library (which might
>> cause both programs to malfunction). It allows for different library
>> versions and because most libraries are only present once (some applications
>> do use the strategy I described for Windows), it's easier to fix bugs. That
>> is IMHO the true power of (a certain) Linux (distribution), the package
>> management system: a unified installation/deinstallation/management system.
>> If you want to know a bit more about this subject: DLL Hell (or dependency
>> hell) is used to describe most problems related to libraries.
>>
>>
>> d) I wouldn't say that that is the most important safetly feature, but it
>> does help. Windows folk usually are used to click every next or OK button
>> that pops up without reading the messag because you get flooded with those
>> messages ("Are you sure you want to do this or that?", click "Next" 20 times
>> to install this or that piece of software, ...). The same with UAC in Vista
>> and Windows 7: it only requires you to click OK to become administrator on
>> most home computers (in companies you have to enter the administrator
>> credentials, which explains why in the office Windows can work). In Linux
>> you have to type your password, so that's when most people think about what
>> they are doing. In general, people are more reluctant to type in a password
>> than to click OK. Some people may find it tedious, that's a little down side
>> to this.
>>
>> On the other hand: Linux has always been a multi user OS (like unix).
>> Windows was a single user OS in the beginning (Windows 1 till Windows Me)
>> and has been adapted (in Windows NT) to handle multiple users. But some
>> features from the old windows era are still present to be able to run old
>> software. In Linux the security features needed in a multi user setup were
>> there by design; in Windows they were built onto the existing code base
>> after a while, so some security code will be sub-optimal.
>>
>> There actually is a lot of standardization, altough some distributions
>> have little differences in the details. Though not every software from any
>> distribution may work on another distribution (I'm currently trying to get a
>> quite old circuit simulator for Red Hat Linux and regular Unix to work on
>> Ubuntu 10.10; easy is a different ball game), but most recent programs and
>> most commonly used programs are distribution independent. A lot of software
>> is common to most distributions (X server, ssh server, Apache, Gnome, ...).
>> This common software base has caused some problems in the past (even with
>> Linux): due to a misconfiguration of OpenSSL (I thought, it was something
>> SSH <http://it.slashdot.org/article.pl?sid=08/05/13/1533212&from=rss>related in any case) at Debian, cryptographic keys generated by computers
>> with Debian (and therefore also Ubuntu) were very weak and easy to crack. At
>> the moment that bug is fixed; but it's just an example to show that a
>> failure at one point can cause a lot of trouble when that part is used in a
>> lot of computers. Software is inherently prone to errors: a lot of functions
>> are used by other functions, so a security issue in one low-level function
>> can cause security issues in hundreds of programs.
>>
>> But indeed diversity is a great way to ensure security. It's indeed harder
>> to find a bug that bother every single Linux computer because Linux
>> computers sometimes have different architectures (all Windows computers use
>> x86 or x86-64 (AMD64); Linux also has support for a lot of other platforms
>> (PowerPC, ARM, Cell, ...)). Actually the same mechanism is used by nature to
>> ensure the survival of species. Let's say you plant one kind of potato
>> plant, all more or less the same, then when a bug comes along that is
>> harmful to one plant, all plants could (and will) get infected. (That has
>> already happened a few times, e.g. Great Famine<http://en.wikipedia.org/wiki/Great_Famine_%28Ireland%29>).
>> When you plant different kinds of potatoes, some plants will get infected
>> but others will survive. As with Linux: because of the differences, this
>> will get you some security. Some servers make use of this principle by not
>> using standard values for the installation.
>>
>> e) There is no real absolute answer to this, because the security holes in
>> Windows do not exist in Linux and vice versa. But at the moment there has
>> been little succes in manufacturing large scale malware for Linux, sure,
>> some do exist (rootkits etc.). Hackers will mostly target Windows because it
>> is easier to succeed in overpowering at least a few machines. For Linux, a
>> lot of computers are servers (more security focussed, both on Linux and
>> Windows) and the defaults are quite sane (or enforced to be sane). In
>> Windows some defaults were/are not sane (passwords etc.), I can't say if the
>> defaults in Windows 7 are all sane, because I mostly choose to set them to
>> sane values anyway
>>
>> http://www.msversus.org/microsoft-windows-performance.html
>>
>> I hope this will help you a bit,
>>
>> Kind Regards
>>
>>
>> Egon.
>>
>>
>>
>> e) That depends on the software you use. Some will run faster in Linux,
>> some in Windows; I guess. But there is some proof that some applications run
>> faster in Wine (Windows API layer for Linux and Mac) than on real Windows
>> (but then on the other hand, Wine does not implement the Windows API
>> entirely and is slower in a lot of cases). In XP some programs might run
>> slower due to the caching differences; but in Vista and 7 performance should
>> be almost the same, I think. Haven't really performed any tests.
>>
>> But what does make a difference is the fact that there is little to no
>> malware for Linux, so you don't really slow down your computer by surfing
>> the internet as is the case with Windows and you don't need a virus scanner,
>> malware scanner to keep your system running.
>>
>>
>> On Thu, Oct 28, 2010 at 11:14, Jan Bongaerts <jbongaerts at gmail.com>wrote:
>>
>>> Unfortunately I won't be there again.
>>>
>>> I'm still compiling some introsession for a school, and could use some
>>> ideas on what to show
>>> 1) using the live CD
>>> 2) using a normally installed system.
>>>
>>> I would like to know the following background info, to answer some
>>> probable questions..
>>>
>>> a) Why does Linux need so little memory to run (min 384MB if I'm not
>>> mistaken), compared to Windows (min 1GB I think)?
>>>
>>> b) Why isn't it necessary to 'defragment' a Linux hard disk, like one
>>> needs to do in Windows?
>>>
>>> c)Confirm that software packages in Linux are much lighter because of the
>>> multi-package structure. If not, please give reason.
>>>
>>> d)Confirm that the most important safety feature in Linux is due to the
>>> fact that you always need a password to become root, and that the second
>>> most important reason is that there is little standardisation, so difficult
>>> to write malware that works on all flavours of the target software.
>>>
>>> e) Confirm that apps usually run faster in Linux than in Windows, because
>>> of the different memory management.
>>>
>>> Those are just some of the things I can think of now.
>>> I'd love to hear feedback from the experts here.
>>>
>>> Regards,
>>> Jan.
>>>
>>>
>>>
>>>
>>> On Wed, Oct 27, 2010 at 9:27 PM, jean7491-Events-Team <
>>> jean7491 at gmail.com> wrote:
>>>
>>>>  Hi to all,
>>>>
>>>> Remember - next IRC meeting  tomorrow Thursday 28/10/2010 at 21.00 hr.
>>>> on #ubuntu-be -- IRC (http://webchat.freenode.net/).
>>>>
>>>> See agenda in wiki https://wiki.ubuntu.com/BelgianTeam/IrcMeetings
>>>>
>>>> --
>>>> jean7491
>>>> Ubuntu Belgium Events Team
>>>>
>>>>
>>>> --
>>>> ubuntu-be mailing list / mailto:ubuntu-be at lists.ubuntu.com
>>>>
>>>> Modify settings or unsubscribe at:
>>>> https://lists.ubuntu.com/mailman/listinfo/ubuntu-be
>>>>
>>>
>>>
>>>
>>> --
>>> Microsoft programs are like Englishmen. They only speak Microsoft.
>>>
>>> --
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>>>
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>>>
>>
>
>
> --
> Microsoft programs are like Englishmen. They only speak Microsoft.
>
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