Re: [CentOS] Moving from Fedora -- Advice??

[David G. Mackay]

On Fri, 2010-12-17 at 18:38 +0100, David Sommerseth wrote:
> On 17/12/10 18:24, Scott Robbins wrote:
> > On Sat, Dec 18, 2010 at 01:11:49AM +0800, Guenther Boelter wrote:
> >> On 12/18/2010 01:04 AM, Beartooth wrote:
> >>>
> >>>   I'm running Fedora14 on all machines, including my wife's -- and
> >>> I'm the nearest (distant) thing there is to tech support.
> >>
> >> What's wrong with Fedora in that case, what do you think is the benefit 
> >> of using CentOS instead?
> > 
> > Fedora will break things.  They're still, in many ways, figuring out
> > what they are, but they do serve as a test bed, or perhaps development
> > platform, for various things that aren't ready for prime time.
> 
> I so often hear that Fedora breaks things.  I've been running F-11 and
> F-12 on a server as KVM host, without issues.  I've been using F8-F13 on
> several computers (3 laptops and a workstation), and I can't really say
> it has broken anything on my setups.  It might be I'm not using it
> "right" to experience such breakage.  Use cases are everything from
> "mail, surf and OO.org" to development tasks

Really?  I've been running KVM on Fedora for quite a few releases.
NetworkManager has been something of a nightmare on several releases
when dealing with VMs.  Especially if you were doing bridging.  Fedora
has a slightly schizophrenic group of publicists.  There are folks that
insist that they are stable, and there are folks that tell you that they
are the leading edge.  If you scan the Fedora devel lists, it's not hard
to find discussions between developers noting that they'll have to force
users to use a particular new feature so that it will get properly
tested (i.e. it's so freaking buggy that no one would use it unless
forced to use it).  That said, I use Fedora for my development systems,
but CentOS for my production systems.

> In fact, for me, Fedora has been way more stable and solid than the time
> I was running Ubuntu (from Gibson to Ibix), where I got worried every
> time there were new updates available.
> 
> But rightfully enough, I've never tried CentOS on the desktop.  Maybe
> CentOS 6 will be a good choice for that.

Depends on what you want for your desktop.  There are a lot of things,
like video, etc., that CentOS just lags too far behind.

Dave


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Re: [CentOS] IPV4 is nearly depleted, are you ready for IPV6?

[David G. Mackay]

On Thu, 2010-12-09 at 08:32 -0500, Adam Tauno Williams wrote:
> On Wed, 2010-12-08 at 16:49 -0600, David G. Mackay wrote:
> > On Wed, 2010-12-08 at 10:41 -0500, Adam Tauno Williams wrote:
> > > On Wed, 2010-12-08 at 09:37 -0600, David G. Mackay wrote:
> > > > On Wed, 2010-12-08 at 10:01 +0100, David Sommerseth wrote:
> > > > > Nope, ARP is gone.  But it gets a replacement as a part of IPv6, 
> > > > > instead
> > > > > of ARP being an addition to IPv4.
> > > > > <http://itkia.com/how-to-arp-a-in-ipv6/>
> > > > > <http://www.tcpipguide.com/free/t_TCPIPIPv6NeighborDiscoveryProtocolND.htm>
> > > > I have a question about how IPV6 interacts with the switches in the
> > > > local network.  Right now, my sub $50(US) gigabit switch from any of
> > > > several vendors keeps an arp table to determine which switch port a
> > > > message will use.  With the huge address space available with IPV6, how
> > > > is that going to work, and when am I going to get a cheap soho switch
> > > > that can handle IPV6?
> > > 
> > > The switch will continue to operate using the MAC# of the client
> > > interfaces.  The switch doesn't care about IPv4, IPv6, or IPX for that
> > > matter [unless you enabled vLANs or managment features - which is a
> > > different issue].
> > Maybe that's the case for my little cheapo soho switch.
> > > The switch does not maintain an "arp table".  It maintains a list of
> > > MAC#s it has seen on each port.
> > Sorry, but that's certainly incorrect for the higher end switches.  
> 
> Hence: "unless you enabled vLANs or managment features - which is a
>  different issue".

Yes, or perhaps a layer 3 switching device.

> > I've accessed the arp table on several different brands of switches.  Also,
> > look up ARP poisoning.
> 
> If the switch has an IPv4 management interface then it has, by
> definition, an ARP table.  ARP is how IPv4 works on Ethernet.  This
> doesn't mean [necessarily] that the switching mechanism is using the ARP
> table to route packets.  If 802.1x or some type of protection scheme is
> not in place all one has to do is forge the MAC address on any traffic
> to 'confuse' the switch.  Specifically ARP cache poising is required to
> get an IPv4 host to misdirect its traffic to another host on the subnet.
> 
> It is very fun to play with this, and Linux makes is pretty easy.
> 
> ip link set address xx:xx:xx:xx:xx:xx dev eth0

Take a look at ettercap.  The idea is to use arp poisoning to overflow
the switch's arp table so that the switch gives up and becomes a hub,
sending traffic out of every port, which allows your friendly local
hacker to view all of the traffic from every port on the switch.  And
no, you don't have to use vlans for this to work.

Let me throw in a disclaimer that it's been over a decade since I played
network manager on a good-sized network that had this kind of gear, so
things have changed a bit since then.  Hopefully, some of the cracks
have been sealed.

Dave


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Re: [CentOS] IPV4 is nearly depleted, are you ready for IPV6?

[David G. Mackay]

On Wed, 2010-12-08 at 10:41 -0500, Adam Tauno Williams wrote:
> On Wed, 2010-12-08 at 09:37 -0600, David G. Mackay wrote:
> > On Wed, 2010-12-08 at 10:01 +0100, David Sommerseth wrote:
> > > Nope, ARP is gone.  But it gets a replacement as a part of IPv6, instead
> > > of ARP being an addition to IPv4.
> > > <http://itkia.com/how-to-arp-a-in-ipv6/>
> > > <http://www.tcpipguide.com/free/t_TCPIPIPv6NeighborDiscoveryProtocolND.htm>
> > I have a question about how IPV6 interacts with the switches in the
> > local network.  Right now, my sub $50(US) gigabit switch from any of
> > several vendors keeps an arp table to determine which switch port a
> > message will use.  With the huge address space available with IPV6, how
> > is that going to work, and when am I going to get a cheap soho switch
> > that can handle IPV6?
> 
> The switch will continue to operate using the MAC# of the client
> interfaces.  The switch doesn't care about IPv4, IPv6, or IPX for that
> matter [unless you enabled vLANs or managment features - which is a
> different issue].

Maybe that's the case for my little cheapo soho switch.

> The switch does not maintain an "arp table".  It maintains a list of
> MAC#s it has seen on each port.

Sorry, but that's certainly incorrect for the higher end switches.  I've
accessed the arp table on several different brands of switches.  Also,
look up ARP poisoning.

Dave


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Re: [CentOS] IPV4 is nearly depleted, are you ready for IPV6?

[David G. Mackay]

On Wed, 2010-12-08 at 10:01 +0100, David Sommerseth wrote:

> Nope, ARP is gone.  But it gets a replacement as a part of IPv6, instead
> of ARP being an addition to IPv4.
> 
> 
> 

I have a question about how IPV6 interacts with the switches in the
local network.  Right now, my sub $50(US) gigabit switch from any of
several vendors keeps an arp table to determine which switch port a
message will use.  With the huge address space available with IPV6, how
is that going to work, and when am I going to get a cheap soho switch
that can handle IPV6?

Dave


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Re: [CentOS] Grub, pata, and sata

[David G. Mackay]

On Wed, 2010-11-24 at 08:05 +0200, cornel panceac wrote:

> every time i reported this bug on some previous fedora versions, it
> was closed with notabug:
> "As mentioned in other bug reports, this isn't really a bug. There's
> no way for
> the drive order to be consistently detected."

It's not a matter of drive order.  Grub simply will not install on hda.  

Even if the order were wrong it should still let me install.  If it was
installing on the wrong drive, that would be a separate issue.

Dave


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Re: [CentOS] Grub, pata, and sata

[David G. Mackay]

On Tue, 2010-11-23 at 22:17 +0100, Tru Huynh wrote:
> On Tue, Nov 23, 2010 at 01:04:03PM -0600, David G. Mackay wrote:
> > 
> > (parted) print
> > all
> > 
> > Model: Hitachi HDT725032VLAT80 (ide)
> > Disk /dev/hda: 320GB
> > Sector size (logical/physical): 512B/512B
> > Partition Table: msdos
> > 
> > Number  Start   EndSize   Type File system  Flags
> >  1  32.3kB  107MB  107MB  primary  ext3 boot 
> >  2  107MB   320GB  320GB  primary   lvm  
> > 
> > 
> > 
> > Model: WDC WD450AA-00BAA0 (ide)
> > Disk /dev/hdb: 45.0GB
> > Sector size (logical/physical): 512B/512B
> > Partition Table: msdos
> > 
> > Number  Start   End SizeType File system  Flags
> >  1  32.3kB  107MB   107MB   primary  ext3 boot 
> >  2  107MB   45.0GB  44.9GB  primary   lvm  
> > 
> > 
> > 
> > Model: ATA SAMSUNG HD502HI (scsi)
> > Disk /dev/sda: 500GB
> > Sector size (logical/physical): 512B/512B
> > Partition Table: msdos
> > 
> > Number  Start   EndSize   Type File system  Flags
> >  1  32.3kB  105GB  105GB  primary  ext3 boot 
> >  2  105GB   500GB  395GB  primary  ext3  
> >  3  500GB   500GB  107MB  primary  ext3  
> > 
> > 
> > Error: Unable to open /dev/md0 - unrecognised disk
> > label. 
> 
> shouldn't have boot,raid flags on the members of tour /dev/md0 array?
> 
> cat /proc/mdstat 
> df -P
> cat /grub/grub.conf (from hda1) and from hdb1

[r...@vorpal ~]# cat /proc/mdstat 
Personalities : 
unused devices: 
[r...@vorpal ~]# df -P
Filesystem 1024-blocks  Used Available Capacity Mounted on
/dev/sda1 99188468   4853368  89215188   6% /
/dev/sda2373793320 235981428 118517828  67% /home/dave
/dev/hda1   101086 25176 70691  27% /boot
/dev/sda3   101105  5665 90219   6% /boot2
tmpfs   647588 0647588   0% /dev/shm
/dev/hdc   4087030   4087030 0
100% /media/CentOS_5.5_Final

[r...@vorpal ~]# cat /boot/grub/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this
file
# NOTICE:  You have a /boot partition.  This means that
#  all kernel and initrd paths are relative to /boot/, eg.
#  root (hd0,0)
#  kernel /vmlinuz-version ro root=/dev/sda1
#  initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-194.26.1.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-194.26.1.el5 ro root=LABEL=/ rhgb quiet
psmouse.proto=bare
initrd /initrd-2.6.18-194.26.1.el5.img

Following is boot from hdb
[r...@vorpal ~]# cat /mnt/util/grub/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this
file
# NOTICE:  You have a /boot partition.  This means that
#  all kernel and initrd paths are relative to /boot/, eg.
#  root (hd1,0)
#  kernel /vmlinuz-version ro root=/dev/VolGroup01/LogVol00
#  initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=5
splashimage=(hd1,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-194.26.1.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-194.26.1.el5 ro root=LABEL=/ rhgb quiet
psmouse.proto=bare
initrd /initrd-2.6.18-194.26.1.el5.img
title CentOS (2.6.18-194.17.1.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-194.17.1.el5 ro root=LABEL=/ rhgb quiet
psmouse.proto=bare
initrd /initrd-2.6.18-194.17.1.el5.img
title CentOS (2.6.18-194.11.3.el5)
root (hd1,0)
kernel /vmlinuz-2.6.18-194.11.3.el5 ro
root=/dev/VolGroup01/LogVol00 rhgb quiet psmouse.proto=bare
initrd /initrd-2.6.18-194.11.3.el5.img
title CentOS5.5 (2.6.18-194.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-194.el5 ro root=LABEL=/ rhgb quiet
psmouse.proto=bare
initrd /initrd-2.6.18-194.el5.img

Thanks,
Dave


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Re: [CentOS] Grub, pata, and sata

[David G. Mackay]

On Tue, 2010-11-23 at 18:12 +, Keith Roberts wrote:
> On Mon, 22 Nov 2010, David G. Mackay wrote:
> 
> > To: centos@centos.org
> > From: David G. Mackay 
> > Subject: [CentOS] Grub, pata, and sata
> > 
> > I've just filed bug 0004634.  Grub won't install onto my pata drive now
> > that I have a sata drive installed.  This is grub 0.97 on CentOS5.5.
> > Has anyone else encountered this?  I'm guessing that I can always
> > install Fedora on hda, which should give me a working grub, but I was
> > hoping for something a little less involved.
> >
> > Thanks,
> > Dave Mackay
> 
> Is the PATA drive on your Primary Master connection?
> 
> If you use Gparted live CD or Parted Magic, how do those 
> drives show up?
> 
> Regards,
> 
> Keith

(parted) print
all

Model: Hitachi HDT725032VLAT80 (ide)
Disk /dev/hda: 320GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   EndSize   Type File system  Flags
 1  32.3kB  107MB  107MB  primary  ext3 boot 
 2  107MB   320GB  320GB  primary   lvm  



Model: WDC WD450AA-00BAA0 (ide)
Disk /dev/hdb: 45.0GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End SizeType File system  Flags
 1  32.3kB  107MB   107MB   primary  ext3 boot 
 2  107MB   45.0GB  44.9GB  primary   lvm  



Model: ATA SAMSUNG HD502HI (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   EndSize   Type File system  Flags
 1  32.3kB  105GB  105GB  primary  ext3 boot 
 2  105GB   500GB  395GB  primary  ext3  
 3  500GB   500GB  107MB  primary  ext3  


Error: Unable to open /dev/md0 - unrecognised disk
label. 

Thanks,
Dave


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[CentOS] Grub, pata, and sata

[David G. Mackay]

I've just filed bug 0004634.  Grub won't install onto my pata drive now
that I have a sata drive installed.  This is grub 0.97 on CentOS5.5.
Has anyone else encountered this?  I'm guessing that I can always
install Fedora on hda, which should give me a working grub, but I was
hoping for something a little less involved.

Thanks,
Dave Mackay


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 15:33 -0500, Les Mikesell wrote:
> David G. Mackay wrote:
> > Well, I try to make my searches specific to what I'm looking for.  The
> > more key words that I can throw at it, the less extraneous cruft comes
> > up.
> 
> That doesn't mesh very well with finding stuff that you don't know 
> exists yet.  For example there is a nice pure-java clone of rrdtool 
> called jrobin that opennms uses to store and graph time-series values. 
> But if you didn't already know that, how would you find it?  Even the 
> bigger things like cifs-in-java don't seem to be very well exposed.

True, but if I don't know that it exists, I'm probably not trying to
find it.  To find out about the items that are, to me, unknown, I do
things like subscribing to technical mailing lists, etc.  Then, there
are sites like java.net that specialize in java.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 15:31 -0500, Lanny Marcus wrote:
> If we had the processing power (and all the incredibly cheap HW that
> exists today), in the 80's, I wouldn't have had to write such
> efficient assembly language code... Much easier today, with cheap RAM,
> etc.  C++ for an old timer, takes awhile to get an understanding of,
> because of the OO, but as a book I have says, before OO, approximately
> 50% of the projects ended in failure. I believe that is on the low
> side. Never used Pascal (wasn't that a teaching language?, but I did
> use PL/M-86.

OO is fine.  Today, at least, there are much better implementations of
in java, python, etc.  C++ is just tortuous.

The pascal p-code implementation was, IIRC, implemented by UCSD.  Pascal
was then popularized by Borland.

Ahh for the good old days, when men were men, and memory upgrades
involved fork lifts.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 13:27 -0700, John R Pierce wrote:
> operating systems,  servers like Apache, Sendmail, Postfix, things like 
> Java JVM innards, those are written in C/C++

Mostly, yes.  There is some assembly in most OSs.  And, they're mostly
in C.  If you have to sink to C++ to get your programmers to code
properly, you need new programmers.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 12:35 -0700, lincohn john wrote:
> Just curious, why not just use C/C++? thanks in advance !
> Lincong

This is a personal opinion, but C++ seems to be an exercise in
masochism.  C is basically a high level assembly language.  Neither are
all that portable.  Granted, for sheer speed, C is probably as good as
you'll get.  Speed just isn't as big a factor these days.  Who knows, if
they'd had the processing power available today back in the 80's, maybe
we'd all be using pascal p-code systems.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 14:30 -0500, Les Mikesell wrote:
> David G. Mackay wrote:
> > 
> >>> Also, there are several engineers at Red Hat that are very unhappy with
> >>> the impact that the 3.0 release is going to have on them.
> >> Yes but it has been obvious for a long time that python does not 
> >> consider backwards compatibility to be important.  This shouldn't have 
> >> come as a surprise.  By comparison, perl has been around longer and 
> > 
> > Judging by some of the comments on the fedora-devel list, it did anyway.
> 
> Maybe some of those developers are young enough to not understand the 
> history.  Or to have learned from experience that it matters.

The ones that I'm thinking about were from the RHEL engineering staff.
That doesn't preclude them from being young, but they were surprised by
the extent of the incompatibilities.  Maybe the young ones are all that
will be left after the ones that are charged with making some of the
Fedora 11 stuff acceptable to a professional user base have committed
ritual sepuku.

> > Google? ;)
> 
> How do you tell google to _not_ give you text matches that are really 
> not about downloadable code modules in the language you want this week?

Well, I try to make my searches specific to what I'm looking for.  The
more key words that I can throw at it, the less extraneous cruft comes
up.

> > I guess the real question is how well java is going to prosper under
> > Oracle's ownership.  Then again, with openjdk, it might not matter too
> > much.
> 
> I don't think that can become much of an issue.  On the other hand, some 
> of the other interesting projects (glassfish, opengrok, etc.) might be 
> more likely to go away or change.

Yeah, I've been tracking the Wonderland project.  So far I haven't heard
much from the development team one way or the other.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 16:12 +0100, Karanbir Singh wrote:
> On 06/15/2009 03:22 PM, David G. Mackay wrote:
> > Python will let you develop programs very quickly, the first time.  The
> > problem is that you'll have to go back and redo the code when a
> > different version of python is released.  There are major
> > incompatibilities between 2.5 and 3.0.
> 
> afaik, this is the first time there is such a major change coming down 
> the python line - even then, I feel its been well documented and there 
> are atleast a couple of automated harness to help along the process.

That's correct, if you stick to pure python coding.  Once again, if you
look at zope, which makes extensive use of the C api, they've had fits
with just about every release.

> I agree its not ideal, far from it - for anyone on any language. But 
> then if you look at it py3 isnt going to be around for c5 or c6, who 
> knows what other tooling might be available further into the future.
> 
> > Also, there are several engineers at Red Hat that are very unhappy with
> > the impact that the 3.0 release is going to have on them.
> 
> But the changes have been known for a while right ? and are'nt most 
> people already making changes that allows their code to migrate well 
> over to 3.0 when its around ?

Probably.  However, most developers would rather spend their resources
on adding new features to their product rather than making changes just
to stay compatible with the current language version.  I believe that,
even with the migration tools, people are still going to have to
manually convert portions of their code.  I haven't really followed it
that closely since I won't be converting more than a few short
scriptlets.

> > The bottom line is that you can probably get your project done faster in
> > python.  But if you have a lot of code that you're going to need to
> > maintain, you're much better off with java, which actually has a lot of
> > input from the user community, and respects their user base.
> 
> Given that large numbers of java people are jumping ship into the ruby 
> camp, I dont know how much of that is really true anymore. More and more 
> of the companies that I know about ( specially the really smart ones ) 
> are either already on ruby for a significant portion of their work, or 
> are in the process of moving.

Sigh.  Yet another language.  I guess that I'll have to take a look at
ruby.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 10:04 -0500, Les Mikesell wrote:
> > Also, there are several engineers at Red Hat that are very unhappy with
> > the impact that the 3.0 release is going to have on them.
> 
> Yes but it has been obvious for a long time that python does not 
> consider backwards compatibility to be important.  This shouldn't have 
> come as a surprise.  By comparison, perl has been around longer and 

Judging by some of the comments on the fedora-devel list, it did anyway.

> through more changes and yet about the only thing you might have to 
> check on a program written for perl 1.x to run under 5.x would be 
> whether you have @ in double-quoted strings that you wanted to remain 
> literal.

I used to do a lot of coding in perl, but I found that I liked python
better.  I still like python for quick and dirty one-offs, but I'm not
going to use it for large and persistent projects.

> One other consideration is that perl probably has the current advantage 
> in terms of available code library modules.  Pretty much anything you 
> can imagine doing has already been done and contributed to CPAN so often 
> the code you have to write yourself is trivial with the modules doing 
> the bulk of the work.  Java may be catching up in this regard but I 
> don't think there is a central place to find available code.

Google? ;)

I guess the real question is how well java is going to prosper under
Oracle's ownership.  Then again, with openjdk, it might not matter too
much.

Dave


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Re: [CentOS] which programming language for server-side admin tasks

[David G. Mackay]

On Mon, 2009-06-15 at 09:16 +0200, Peter Hopfgartner wrote:
> Python has become quite common for sysadmin stuff. Indeed, a lot of 
> RedHat/Fedora (e.g. anaconda, the installer) and Ubuntu tools are really 
> Python scripts. The code is quite readable and usually, there are Python 
> bindings for almost every popular C library.

Python will let you develop programs very quickly, the first time.  The
problem is that you'll have to go back and redo the code when a
different version of python is released.  There are major
incompatibilities between 2.5 and 3.0.  If you have a lot of code and/or
use the low level C bindings, it can be a major effort to make your code
run under a new release.  Take a look at the poor folks at zope.org.
They've been beaten half to death with almost every release.

Also, there are several engineers at Red Hat that are very unhappy with
the impact that the 3.0 release is going to have on them.

> GUI can quickly be made with PyGTK or WxPython.

And, of course, there's glade to help.

The bottom line is that you can probably get your project done faster in
python.  But if you have a lot of code that you're going to need to
maintain, you're much better off with java, which actually has a lot of
input from the user community, and respects their user base.

Dave


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Re: [CentOS] Programming ressources

[David G. Mackay]

On Fri, 2009-01-09 at 10:55 -0500, Guy Boisvert wrote:
> Hi!

Hello Guy.

>   It may be a little OT but i'm searching for a c/c++ programmer for the 
> development of a remote controlled multimedia player that would run 
> under CentOS with Aja OEM card.  We'd use this player in our fully 
> automatic TV broadcast system.
> 
>   We currently have a player (developed in house) that works mostly ok on 
> Winblows but it lacks many features like remote monitoring (SNMP or 
> something like that), fault management, etc.  The code is not documented 
> and there are problems migrating from Stradis SDM-275 card to SDM-290, 
> from Win2000 to XP, etc.

A quick look on the Stradis web site didn't really tell me whether
Stradis (or Vitec Multimedia, now) has linux drivers available for their
cards.  If not, do they provide enough hardware documentation to write
drivers?  I didn't bother to set up a login on their site, so that
information might be available.

>   I was thinking that their should be programmers on the CentOS mailing 
> list.  Sorry if i bother other list members with my request.

I have done a lot of programming in C, but not C++.  I was on a project
to prototype a media player for use in the United States running under
linux.  Technically, there's not too much of a problem.  Legally, at
least at the time, there were some major problems under U. S. law
concerning patent and licensing issues, but we were mostly looking at
using software codecs to handle viewing.  That may not be a problem in
Canada, and your use of hardware decoders may bypass that in either
case.

>   We are based in Montréal, Province of Quebec, Canada.  Frankly, we have 
> to find a Winblows programmer first to evaluate the documentationless 
> code we have for our current player.  With the obligation to go digital 
> and the fact that we may even have to go HD, we'll want to go Linux and 
> get an ultra-stable platform.

What is your time frame?  Centos 6 should be coming within the next year
or so.  Centos 5.3 should be out in months.  Then again, you might be
able to do everything that you need under the current Centos releases.

Also, what is your code handling?  I can also do Windows programming in
C (among other languages, but not including C++).

>   It would be nice to evaluate if something like VLC or MPLayer could 
> provide the functionality we want too.

They can both do a good job manipulating multimedia streams.  Once
again, I'd be more concerned about legal and licensing issues.  There
has been a recent court decision in the U. S. that may invalidate
software patents, but it could be reversed, and is unlikely to be
resolved anytime soon.

I would certainly be interested in hearing more about what you're doing.
And I would love to be able to provide consulting services to you.

Thank you,

David Mackay


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Re: [CentOS] how can I stress a server?

[David G. Mackay]

On Tue, 2008-11-18 at 16:48 +0200, Rudi Ahlers wrote:
> I have the exact same setup on a few other machines, using Gigabyte
> motherboards + 4GB RAM. Other than that, the HDD's are the same, the
> OS is the same, and HyperVM is the same. I basically run yum upgrade
> once a week on all the machines. The only difference is this one has
> an Intel DG35EC motherboard with a Q9300 Quad Core CPU on it, which is
> supposed to be more power efficient than some of the Core 2 Duo CPU's
> on the other machine.
> 
> As a matter of interest, all 5 Virtual Machines have been running on a
> Gigabyte motherboard + i6450 CPU + 4GB RAM since yesterday, and it's
> very very stable.
> 
> 
> So, my thinking is, it's the motherboard. It could also be the RAM,
> but I'm not 100% sure yet. The machine had 4GB initially, and then I
> added another 4GB hoping the problem would go away, but it didn't.

I seem to recall that one of the differences between AMD and Intel
virtualization is that AMD chips have additional memory management
capabilities that are specific to virtualization on the CPU chip, where
Intel processors require additional support circuitry.  The fact that
your problems surface when you're running xen suggests that possibly the
additional support isn't functioning correctly.  Is it possible that
there's some obfuscated BIOS setting that's necessary to enable it, or
that it's just not present on the motherboard?

Dave


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Re: [CentOS] Simple audio recording app?

[David G. Mackay]

On Sun, 2008-10-26 at 12:49 -0500, Lanny Marcus wrote:

> No intention of hijacking your thread, but I'm also using GNOME and
> fully up to date CentOS 5.2 (32 bit).  No audio output from the
> microphone  Niki: I hope we can get this to work! Lanny

I was having a terrible time trying to get microphone input on my fedora
system.  I tried all sorts of contortions with alsamixer, etc.  Then, in
the process of installing openmovieeditor, I had to install the gmerlin
packages.  I tried setting up the mic using the gmerlin mixer, and
voila!  This is on a system using an nvidia chipset that mimics an intel
hda sound card.

Dave


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Re: [CentOS] Re: Ole Fossils [ was Re: ls and rm: "argument list too long"]

[David G. Mackay]

On Sat, 2008-10-25 at 15:03 -0700, Steven Vishoot wrote:

> Gees i feel like i am at an ole farts convention, with this thread. :-D

Run along home, sonny. :)

Dave


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Re: [CentOS] Re: Ole Fossils [ was Re: ls and rm: "argument list too long"]

[David G. Mackay]

On Sat, 2008-10-25 at 15:02 -0700, Bill Campbell wrote:

> The COMNET time sharing service in D.C. used the B-5500.  It was formed by
> several ex G.E. time sharing people, and we were one of their first beta
> (and largest) customers, so I tended to get what I asked for.  On the other
> hand if something went wrong, and they saw me on the system, I usually got
> the blame :-).

You should have charged extra for helping to harden the system.

> >No, I was just young and foolish.  Then someone explained that Burroughs
> >wanted to get their techs hired away by the customers.  They'd most
> >likely continue to support Burroughs equipment, but on someone else's
> >nickel.
> 
> That sounds like Burroughs.  Ray MacDonald, Burroughs Chairman, was quoted
> in an interview in Fortune magazine saying their goal was to keep their
> customers ``surly but not rebellious''.

Too bad he didn't give his employees that much concern.  There's another
story that when Michael Blumenthal became chairman, he asked for a list
of all the salesmen that were making six figures.  He was told that
there were none.

> I think that was because I always had an excellent relationship with the
> support people, and made some good contacts at the annual CUBE meetings.
> It always helps to have low friends in high places.

Burroughs technical employees were almost always happy to let someone
else buy them drinks.

> I have always thought that a major problem with Microsoft software is that
> it is largely written by young, inexperienced people who had little or no
> understanding of networking, security, or multi-user systems.  My brother
> is one of the few people I know who worked for Microsoft who had major
> experience on Real systems(TM) (DEC, Prime, etc.)  before going to MS.

It'll be interesting to see what happens now that they got religion
concerning the utility computing trend.  What they've always had is
marketing capability.  Otherwise, why would anyone run MS Office as
opposed to Open Office?

Dave


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Re: [CentOS] Re: Ole Fossils [ was Re: ls and rm: "argument list too long"]

[David G. Mackay]

On Sat, 2008-10-25 at 12:10 -0700, Bill Campbell wrote:

> My first Burroughs experience was on the B-5500, and it had some
> ``interesting'' quirks.  Using Burroughs extended ALGOL, one could do what
> they called array row writes to very efficiently write large chunks of
> memory with a single hardware command.  The hitch was that if one tried to
> write more than 1024 48bit words, it would crash the entire system, with a
> side effect of losing the accounting information for all running programs,
> which could be useful when paying $750/hour for time sharing :-).

I'm surprised that the bug lasted very long, or did it just go
unreported? ;)

> Are you retired Air Farce?  A fair number of Burroughs field engineers had
> learned the Burroughs equipment in the AF (and could afford to work at BGH
> low pay because of their retirement pay).

No, I was just young and foolish.  Then someone explained that Burroughs
wanted to get their techs hired away by the customers.  They'd most
likely continue to support Burroughs equipment, but on someone else's
nickel.

> One might say that I worked for Burroughs too as I debugged their Remote
> Job Entry (RJE) software for Medium systems, including patching MCP,
> because the company I worked for needed it to work.  I talked Burroughs out
> of the source code for RJE and the current version of MCP so that I could
> fix things.  After I sent them the fixes, I never had any problem getting
> anything I asked for.

It's impressive that you managed to talk them out of the source, and
that you fixed it.

> FWIW, the entire source code listing for MCP fit in a single file drawer.
> Reading the comments in the code, it was obvious that a very small group of
> people worked on it which resulted in quite nice integration and
> consistency.

Legend had it that the medium systems MCP was mostly written by one guy
who lived in a beach house in California with two women.

> Can you imagine`Microsoft making the source code for Windows available to a
> small customer for free, and with no NDA so the customer could fix a
> problem that was critical to them?  Even if they supplied the source, do
> you think anybody could figure it out?

Well, I did have a go at their Device Driver kit at one point.
Convoluted is the first printable word that comes to mind.

> One of the most important features of open source software is the
> availability of the source code so people can quickly fix bugs critical to
> them or add features they need.  As an example, in January 2000, groff had
> a y2k problem with dates which I found printing a letter that needed to go
> out.  It took me about 15 minutes to find the problem in the code, fix it,
> and send that patch back to the maintainers.  Imagine how long it would
> take to get a similar problem fixed in M$-Word.

Yes.  Trying to support a black box (It took YEARS before they released
the source code to the B1xx systems to their support employees outside
of the plant) made me a firm believer in open source.

Dave


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Re: [CentOS] Re: Ole Fossils [ was Re: ls and rm: "argument list too long"]

[David G. Mackay]

On Sat, 2008-10-25 at 10:30 -0700, Bill Campbell wrote:

> And our Burroughs B-3500 would run circles around the 360/50.
> The Burroughs had a whopping 200KB of memory, ran an average of
> 20 jobs in the mix, and didn't require 40 JCL cards to compile
> and run a one line Hello World FORTRAN program.

The good old Master Control Program at work.

> Burroughs invented virtual memory in the early 60s in their large
> systems allowing them to run large programs in small memory.
> When IBM invented thrashing, called it virtual memory, the
> minimum memory requirements to run it was 1MB requiring major
> updgrades to support it.  IBM never wrote a line of code that
> was not designed to sell more hardware.

Of course, there was the time that the large systems group put the
segment-not-present handler in an overlayable segment.  The good folks
at the factory had machines with max memory, so it wasn't a problem for
them.  It was a nice hard hang for those that didn't have enough memory.

> Bringing this back to Linux, at that time IBM occupied the place
> of honor that Microsoft has now with an effective monopoly, a
> cumbersome and inefficient system requiring an army of support
> people to keep it running, and required constant patching.

Yes, but at least IBM tested their equipment, and HAD sufficient support
folks.  I used to work for Burroughs, and that was a source of
frustration for all concerned.

Dave


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Re: [CentOS] Re: Ole Fossils [ was Re: ls and rm: "argument list too long"]

[David G. Mackay]

On Sat, 2008-10-25 at 12:16 -0400, William L. Maltby wrote:
> On Sat, 2008-10-25 at 12:14 -0400, William L. Maltby wrote:
> > 
> 
> > Circa 1971/2(?), we had an IBM S360/30 with 64K (that's right, "K", "M")
> s/"M"/not "M"/

Yep.  The first computer I programmed on was an IBM 1130 with 16K of
core.  You could power down for the weekend, and the memory contents
would still be there when you powered up on Monday.

Dave


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Re: [CentOS] Re: Ole Fossils [ was Re: ls and rm: "argument list too long"]

[David G. Mackay]

On Fri, 2008-10-24 at 18:09 -0700, Bill Campbell wrote:

> The Burroughs Medium Systems mainframes I worked on allowed one to store
> the program on disk, then compile with modifications in a card deck, using
> the sequence numbers to replace or insert lines from the cards.  There were
> options to create a new disk file with the patches included, and to
> resquence the source on disk.  Typically there were several card desks in a
> drawer which could be loaded to recreate the patched disk file by loading
> them in sequence which was fine until the disk file was resequenced when it
> was time to punch new cards from the disk file to replace the original deck
> and patches.  Punch cards were far more reliable backup than mag tape and
> in a pinch one could read the printing on the card to fix a badly damaged
> card (it was amazing how fast a card reader jam could turn the first card
> into an accordian fold).

Then came CANDE, TD8xx terminals, and editing on your head-per-track
disk.  Ah for the good old days, when men were men, and memory upgrades
involved fork lifts.

Dave


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Re: [CentOS] Latest samaba updates

[David G. Mackay]

On Fri, 2008-07-11 at 09:09 -0400, Filipe Brandenburger wrote: 
> On Fri, Jul 11, 2008 at 8:24 AM, David G. Mackay <[EMAIL PROTECTED]> wrote:
> > Thanks, I will remember.  Now I just need to find out what it means by
> > read-only.  A find -perm 400 on the directory gives no hits, nor do most
> > other variations, like 444, etc.
> 
> Try:
> 
> find . \! -perm /222
> 
> See "man find" for details.

Thank you.  The other question is whether selinux is concerned about a
file being r/o at the owner, group, or anonymous level.  Is 644 OK, or
640, or 644?

Dave


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Re: [CentOS] CentOS 5.2 VMI support

[David G. Mackay]

On Thu, 2008-07-10 at 17:31 -0700, nate wrote:
> No it requires changes to the kernel itself, changes which I don't think Red
> Hat will introduce in a minor release as their current VM stuff is Xen based
> which has it's own paravirtualization support in the existing kernel(pre
> VMI). I read that Red Hat is moving towards KVM though, I don't have any
> knowledge on that project, maybe it uses VMI as well.

There's a big splash on Redhat's home page.  Take a look at
http://www.ovirt.org.  That uses libvirt.

Dave


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RE: [CentOS] Latest samaba updates

[David G. Mackay]

On Thu, 2008-07-10 at 12:32 -0400, John wrote:
> Remember this. It is going to work when set to Permisive regardless!! 

Thanks, I will remember.  Now I just need to find out what it means by
read-only.  A find -perm 400 on the directory gives no hits, nor do most
other variations, like 444, etc.

Dave


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RE: [CentOS] Latest samaba updates

[David G. Mackay]

On Wed, 2008-07-09 at 02:33 -0400, John wrote:
> Did it give you a rpm.new.smb.config file on update of Samba? Users file
> also? I would first check my Selinux file Permissions for Samba. Then file
> permissions on the shared directories and also make sure that they are
> replicating on the file in the directory.
> 
> My idea would be disable SE Linux then make sure all you permissions are
> correct for the shares, then enable selinux. From you bug report it looks
> like permision problems. Also you have new selinux options in your smb.conf
> file, so check them out also.

The plot thickens.  I set selinux to permissive, and was able to log in
from the windows VM.  Next, I set up a new CentOS5.2 VM, and got samba
going on it.  Then I updated everything but the samba and selinux policy
packages and everything still worked.  Finally, I added the samba and
selinux packages, and everything worked as it should.  I have no idea
what set of circumstances led to the original failure.  I guess I'll
just have to reinstall Centos on the real iron.

Dave


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[CentOS] Latest samaba updates

[David G. Mackay]

When I let yum install the latest samba updates, it ate my smb users
file and smb.conf.  Once I restored those, it gave me several selinux
avc denials, one of which I can't clear up.  See
http://bugs.centos.org/view.php?id=2965 for details.

Anyone else having problems like this?

Dave


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Re: [CentOS] clustered mail server?

[David G. Mackay]

On Sat, 2008-05-17 at 10:30 +0200, Rudi Ahlers wrote:
> Thank you for your input. I can't justify exchange (and don't want MS) 
> for 10 users. I do want IMAP though, and the calendar & address book 
> would be nice. This IMO has nothing todo with CentOS though, but at the 
> same time it shouldn't be limited to which Linux distro I'm using. As 
> you have said I may need to look at file system clustering instead, but 
> have never attempted it, so I don't know where to begin even. I know a 
> lot of MTA's can support a central user DB, but that won't sync the 
> emails. And this won't be a commercial installation either, it's for a 
> for a project in a rural community about 700km's from me, so it's more a 
> matter of if 1 server dies / crashes / packes up, and I can only get to 
> it 5 days later, the mail server still works :)

You might take a look at SquirrelMail.  It integrates well with cyrus
imap.

Dave


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Re: [CentOS] Internet Load Balancing and Failover

[David G. Mackay]

On Sun, 2008-02-24 at 09:39 -0800, nate wrote:
> Shawn Everett wrote:
> > Hi All,
> >
> > Does anyone have any experience connecting two or more DSL/Cable modems to
> > a Linux box to provide load balancing and failover?
> 
> I haven't tried this on linux but it appears trivial in OpenBSD:
> http://www.openbsd.org/faq/pf/pools.html#outgoing
> 
> I personally prefer OpenBSD for firewalls/gateways over Linux.
> I love linux for pretty much all purposes except firewalls/gateways,
> and I don't use OpenBSD for anything other than firewalls/gateways.
> Mainly because of packet filter(pf), it's a wonderful tool.
> 
> I tried looking at some documentation for iptables for doing the
> same thing but it was pretty vague. I didn't notice anything
> similar to what pf can do in the document above. Closest I found
> was:
> http://www.netfilter.org/documentation/HOWTO//NAT-HOWTO-6.html#ss6.3

I did this a couple of years ago with dsl and a cable modem.  Take a
look at the Adv-Routing-HOWTO on tldp.org.

Dave


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