Since very early 2.4 somewhere it has been impossible to use my two
wireless cards, a NetGear ME401 and a Lucent card (both
orinoco-based). Both are able to load the modules when pluggen in, but
trying to use them is futile, as nothing gets transmitted, and dmesg
show tons of this:
eth1: Station identity 001f:0006:0001:0003
eth1: Looks like an Intersil firmware version 1.03
eth1: Ad-hoc demo mode supported
eth1: IEEE standard IBSS ad-hoc mode supported
eth1: WEP supported, 104-bit key
eth1: MAC address 00:09:5B:27:DC:F9
eth1: Station name "Prism I"
eth1: ready
eth1: index 0x01: Vcc 5.0, irq 6, io 0x0100-0x013f
NETDEV WATCHDOG: eth1: transmit timed out
eth1: Tx timeout! Resetting card. ALLOCFID=0128, TXCOMPLFID=0127, EVSTAT=800c
eth1: Error -110 writing packet to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: Error -110 writing Tx descriptor to BAP
NETDEV WATCHDOG: eth1: transmit timed out
eth1: Tx timeout! Resetting card. ALLOCFID=0128, TXCOMPLFID=0127, EVSTAT=800c
The situation is similar for both cars, and I'm wondering if this is
a known broken setup, or I've messed up?
Currnently I'm on 2.4.20, tried both with and without the ACPI and
preempt patches (vmware deosnt make a difference either), the hardware
is a Compaq Evo n800c notebook and this is the cardbus bridge:
02:06.0 CardBus bridge: Texas Instruments PCI1410 PC card Cardbus Controller (rev 02)
Subsystem: Compaq Computer Corporation: Unknown device 004a
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66Mhz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 168, cache line size 20
Interrupt: pin A routed to IRQ 11
Region 0: Memory at 40000000 (32-bit, non-prefetchable) [size=4K]
Bus: primary=02, secondary=03, subordinate=03, sec-latency=176
Memory window 0: 30400000-307ff000 (prefetchable)
Memory window 1: 30800000-30bff000
I/O window 0: 00004800-000048ff
I/O window 1: 00004c00-00004cff
BridgeCtl: Parity- SERR- ISA- VGA- MAbort- >Reset+ 16bInt+ PostWrite+
16-bit legacy interface ports at 0001
mvh,
A
--
Alexander Hoogerhuis | [email protected]
CCNP - CCDP - MCNE - CCSE | +47 908 21 485
"You have zero privacy anyway. Get over it." --Scott McNealy
Hi,
Are you using the modules from the kernel source or from pcmcia-cs? Are
you using yenta_socket or pcmcia-cs? pcmcia-cs has given me a lot more
positive results than trying to use yenta_socket and the built in kernel
modules. Also, try binding your card IDs to use wavelan_cs instead and
see if it works (maybe those cards are a bit older and as such need
older drivers.)
Also see if /sbin/iwconfig (hopefully you have this gem installed, it's
wireless-tools by Jean Tourrilhes @
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Tools.html) gives
you any useful information. Is it picking up an AP?
Finally, ACPI might not make a difference, but see if enabling or
disabling APM does.
Hope this helps you.
Regards
-Josh
I have nearly the same setup as you
Rabid cheeseburgers forced Alexander Hoogerhuis<[email protected]> to
write this on 24 Dec 2002 18:10:29+0100:
> Since very early 2.4 somewhere it has been impossible to use my two
> wireless cards, a NetGear ME401 and a Lucent card (both
> orinoco-based). Both are able to load the modules when pluggen in, but
> trying to use them is futile, as nothing gets transmitted, and dmesg
> show tons of this:
>
> eth1: Station identity 001f:0006:0001:0003
> eth1: Looks like an Intersil firmware version 1.03
> eth1: Ad-hoc demo mode supported
> eth1: IEEE standard IBSS ad-hoc mode supported
> eth1: WEP supported, 104-bit key
> eth1: MAC address 00:09:5B:27:DC:F9
> eth1: Station name "Prism I"
> eth1: ready
> eth1: index 0x01: Vcc 5.0, irq 6, io 0x0100-0x013f
> NETDEV WATCHDOG: eth1: transmit timed out
> eth1: Tx timeout! Resetting card. ALLOCFID=0128, TXCOMPLFID=0127,
> EVSTAT=800c eth1: Error -110 writing packet to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> NETDEV WATCHDOG: eth1: transmit timed out
> eth1: Tx timeout! Resetting card. ALLOCFID=0128, TXCOMPLFID=0127,
> EVSTAT=800c
>
> The situation is similar for both cars, and I'm wondering if this is
> a known broken setup, or I've messed up?
>
> Currnently I'm on 2.4.20, tried both with and without the ACPI and
> preempt patches (vmware deosnt make a difference either), the hardware
> is a Compaq Evo n800c notebook and this is the cardbus bridge:
>
> 02:06.0 CardBus bridge: Texas Instruments PCI1410 PC card Cardbus
> Controller (rev 02)
> Subsystem: Compaq Computer Corporation: Unknown device 004a
> Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
> ParErr- Stepping- SERR- FastB2B- Status: Cap+ 66Mhz- UDF-
> FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR-
> <PERR- Latency: 168, cache line size 20
> Interrupt: pin A routed to IRQ 11
> Region 0: Memory at 40000000 (32-bit, non-prefetchable)
> [size=4K] Bus: primary=02, secondary=03, subordinate=03,
> sec-latency=176 Memory window 0: 30400000-307ff000
> (prefetchable) Memory window 1: 30800000-30bff000
> I/O window 0: 00004800-000048ff
> I/O window 1: 00004c00-00004cff
> BridgeCtl: Parity- SERR- ISA- VGA- MAbort- >Reset+ 16bInt+
> PostWrite+ 16-bit legacy interface ports at 0001
>
> mvh,
> A
> --
> Alexander Hoogerhuis | [email protected]
> CCNP - CCDP - MCNE - CCSE | +47 908 21 485
> "You have zero privacy anyway. Get over it." --Scott McNealy
> -
> To unsubscribe from this list: send the line "unsubscribe
> linux-kernel" in the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
Joshua Kwan
[email protected]
pgp public key at http://joshk.mspencer.net/pubkey_gpg.asc
Joshua Kwan <[email protected]> writes:
> Hi,
>
> Are you using the modules from the kernel source or from pcmcia-cs? Are
> you using yenta_socket or pcmcia-cs? pcmcia-cs has given me a lot more
> positive results than trying to use yenta_socket and the built in kernel
> modules. Also, try binding your card IDs to use wavelan_cs instead and
> see if it works (maybe those cards are a bit older and as such need
> older drivers.)
>
Avoiding the kernel-side PCMCIA-stuff and using the standalone package
got me a lot further. After a few tweaks int he config files I get the
interface up and things startes to happen:
lapper root # ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:09:5B:27:DC:F9
inet addr:172.31.255.242 Bcast:172.31.255.247 Mask:255.255.255.248
inet6 addr: fe80::209:5bff:fe27:dcf9/10 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:3 errors:8 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:0 (0.0 b) TX bytes:516 (516.0 b)
Interrupt:11 Base address:0x100
lapper root # iwconfig eth1
Warning: Driver for device eth1 has been compiled with version 14
of Wireless Extension, while this program is using version 13.
Some things may be broken...
eth1 IEEE 802.11-DS ESSID:"humbug" Nickname:"lapper.ihatent.com"
Mode:Ad-Hoc Frequency:2.417GHz Cell: 02:09:A7:FB:DC:F9
Bit Rate:11Mb/s Tx-Power=15 dBm Sensitivity:1/3
Retry min limit:8 RTS thr:off Fragment thr:off
Encryption key:6875-6262-61 Encryption mode:open
Power Management:off
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
Seems I need to get the wireless tools rebuilt and I'll be in touch
with a WLAN in a few hours, but this all seems swell now.
After inserting the card (NetGear MA401) I get this in my log tho:
eth1: Station identity 001f:0006:0001:0003
eth1: Looks like an Intersil firmware version 1.03
eth1: Ad-hoc demo mode supported
eth1: IEEE standard IBSS ad-hoc mode supported
eth1: WEP supported, 104-bit key
eth1: MAC address 00:09:5B:27:DC:F9
eth1: Station name "Prism I"
eth1: ready
eth1: index 0x01: Vcc 5.0, irq 11, io 0x0100-0x013f
eth1: Error -110 setting multicast list.
eth1: Error -110 setting multicast list.
eth1: Error -110 setting multicast list.
eth1: Error -110 setting multicast list.
eth1: Error -110 setting multicast list.
eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
eth1: Error -110 writing packet to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: Error -110 writing Tx descriptor to BAP
eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
If you have an idea about the errors, drop me a line, and if not I'll
dig into it :)
mvh,
A
> Hope this helps you.
> Regards
>
> -Josh
>
Sure did :)
-A
--
Alexander Hoogerhuis | [email protected]
CCNP - CCDP - MCNE - CCSE | +47 908 21 485
"You have zero privacy anyway. Get over it." --Scott McNealy
Thanks
"Joshua M. Kwan" <[email protected]> writes:
> > Warning: Driver for device eth1 has been compiled with version 14
> > of Wireless Extension, while this program is using version 13.
> > Some things may be broken...
>
> First of all, what kernel are you using? That's an ancient version of
> the WE. If this is 2.4.2[01], download the following diffs from Jean's
> fine site:
>
> * http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw240_we15-6.diff
> * http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw241_we16-3.diff
>
I'll have a look in there. I'm on 2.4.20 with acpi and preempt patches
applied in that order. In addition I'm using pcmcia-cs and not the
built-in stuff. I'm fixing that on another machine here now so that I
can try it out, but it seems to give me no grief and no worries or
errors starting it up and plugging the card in, and PnP finds
resources nicely and I get a nice double beep to indicate all went
well, assigning IPs and everything looks sane.
I'll try later tonight to go for the newer stuff.
> Patch these against the top of your source tree with -p1. This might fix
> your problem, otherwise it's just eliminating one potential cause of the
> problem. Then copy include/linux/wireless.h to
> /usr/include/linux/wireless.h, so that things that require WE to compile
> (notably pcmcia-cs' wireless modules) will be using the right version.
>
> Next of all, try upgrading the firmware on your card.
>
WIll do.
> The error writing packet to BAP error always seemed just like a small
> nuisance to me during large file transfers. It did not correlate with
> any connectivity problems, so I just commented it out in the
> orinoco/hermes/orinoco_cs source (it's in one of those files.)
>
> Yes, rebuild wireless-tools once you have patched to WE16 and copied it
> to /usr/include. If you use debian, the easiest way is to apt-get source
> wireless-tools and just tweak it to look at wireless.h v16, then
> fakeroot debian/rules binary and replace your package with that. This is
> probably feasible with SRPMs too, but I don't know how.
>
I'm on gentoo :)
> Hope your wireless endeavors succeed - I just spent all week getting
> hostap_plx to work (and I'm now reaping the benefits because I now have
> wifi access all over my house) :)
>
I'm trying to solve a 2 meter stretch here, but I also want to get
ready as I always seem to bump into an airport or hotell with WLAN,
and end up having to use it from Windows. And that's boring. :)
> Regards
> -Josh
mvh,
A
--
Alexander Hoogerhuis | [email protected]
CCNP - CCDP - MCNE - CCSE | +47 908 21 485
"You have zero privacy anyway. Get over it." --Scott McNealy
> Warning: Driver for device eth1 has been compiled with version 14
> of Wireless Extension, while this program is using version 13.
> Some things may be broken...
First of all, what kernel are you using? That's an ancient version of
the WE. If this is 2.4.2[01], download the following diffs from Jean's
fine site:
* http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw240_we15-6.diff
* http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw241_we16-3.diff
Patch these against the top of your source tree with -p1. This might fix
your problem, otherwise it's just eliminating one potential cause of the
problem. Then copy include/linux/wireless.h to
/usr/include/linux/wireless.h, so that things that require WE to compile
(notably pcmcia-cs' wireless modules) will be using the right version.
Next of all, try upgrading the firmware on your card.
The error writing packet to BAP error always seemed just like a small
nuisance to me during large file transfers. It did not correlate with
any connectivity problems, so I just commented it out in the
orinoco/hermes/orinoco_cs source (it's in one of those files.)
Yes, rebuild wireless-tools once you have patched to WE16 and copied it
to /usr/include. If you use debian, the easiest way is to apt-get source
wireless-tools and just tweak it to look at wireless.h v16, then
fakeroot debian/rules binary and replace your package with that. This is
probably feasible with SRPMs too, but I don't know how.
Hope your wireless endeavors succeed - I just spent all week getting
hostap_plx to work (and I'm now reaping the benefits because I now have
wifi access all over my house) :)
Regards
-Josh
On Mon, Dec 30, 2002 at 05:17:26AM +0100, Alexander Hoogerhuis wrote:
> Joshua Kwan <[email protected]> writes:
>
> > Hi,
> >
> > Are you using the modules from the kernel source or from pcmcia-cs? Are
> > you using yenta_socket or pcmcia-cs? pcmcia-cs has given me a lot more
> > positive results than trying to use yenta_socket and the built in kernel
> > modules. Also, try binding your card IDs to use wavelan_cs instead and
> > see if it works (maybe those cards are a bit older and as such need
> > older drivers.)
> >
>
> Avoiding the kernel-side PCMCIA-stuff and using the standalone package
> got me a lot further. After a few tweaks int he config files I get the
> interface up and things startes to happen:
>
> lapper root # ifconfig eth1
> eth1 Link encap:Ethernet HWaddr 00:09:5B:27:DC:F9
> inet addr:172.31.255.242 Bcast:172.31.255.247 Mask:255.255.255.248
> inet6 addr: fe80::209:5bff:fe27:dcf9/10 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:3 errors:8 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> RX bytes:0 (0.0 b) TX bytes:516 (516.0 b)
> Interrupt:11 Base address:0x100
>
> lapper root # iwconfig eth1
> Warning: Driver for device eth1 has been compiled with version 14
> of Wireless Extension, while this program is using version 13.
> Some things may be broken...
>
> eth1 IEEE 802.11-DS ESSID:"humbug" Nickname:"lapper.ihatent.com"
> Mode:Ad-Hoc Frequency:2.417GHz Cell: 02:09:A7:FB:DC:F9
> Bit Rate:11Mb/s Tx-Power=15 dBm Sensitivity:1/3
> Retry min limit:8 RTS thr:off Fragment thr:off
> Encryption key:6875-6262-61 Encryption mode:open
> Power Management:off
> Link Quality:0 Signal level:0 Noise level:0
> Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
> Tx excessive retries:0 Invalid misc:0 Missed beacon:0
>
> Seems I need to get the wireless tools rebuilt and I'll be in touch
> with a WLAN in a few hours, but this all seems swell now.
>
> After inserting the card (NetGear MA401) I get this in my log tho:
>
> eth1: Station identity 001f:0006:0001:0003
> eth1: Looks like an Intersil firmware version 1.03
> eth1: Ad-hoc demo mode supported
> eth1: IEEE standard IBSS ad-hoc mode supported
> eth1: WEP supported, 104-bit key
> eth1: MAC address 00:09:5B:27:DC:F9
> eth1: Station name "Prism I"
> eth1: ready
> eth1: index 0x01: Vcc 5.0, irq 11, io 0x0100-0x013f
> eth1: Error -110 setting multicast list.
> eth1: Error -110 setting multicast list.
> eth1: Error -110 setting multicast list.
> eth1: Error -110 setting multicast list.
> eth1: Error -110 setting multicast list.
> eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
> eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
> eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
> eth1: Error -110 writing packet to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: Error -110 writing Tx descriptor to BAP
> eth1: This firmware requires an ESSID in IBSS-Ad-Hoc mode.
>
> If you have an idea about the errors, drop me a line, and if not I'll
> dig into it :)
>
> mvh,
> A
>
> > Hope this helps you.
> > Regards
> >
> > -Josh
> >
>
> Sure did :)
>
> -A
>
> --
> Alexander Hoogerhuis | [email protected]
> CCNP - CCDP - MCNE - CCSE | +47 908 21 485
> "You have zero privacy anyway. Get over it." --Scott McNealy
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
"Joshua M. Kwan" <[email protected]> writes:
> > Warning: Driver for device eth1 has been compiled with version 14
> > of Wireless Extension, while this program is using version 13.
> > Some things may be broken...
>
> First of all, what kernel are you using? That's an ancient version of
> the WE. If this is 2.4.2[01], download the following diffs from Jean's
> fine site:
>
> * http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw240_we15-6.diff
> * http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw241_we16-3.diff
>
No warnings anymore, and it all works. I now have a full 2 yards of
wireless netowrk and dont have to run a cat5 over to muy couch :)
Apart from that, Jean Tourrilhes' site was a treasure of HOWTOs and
FAQs, so I'll spend a lot of time reading up there. Next thing up is
bluetooth, and the site seems to be the right place for that, too.
> Next of all, try upgrading the firmware on your card.
>
Went trough the motions of finding NetGears support on this. NetGear
now officially has landed on my list of gear not to recommend. The
while sitiation on finding firmware and tools to flash it didn't
strike me as very orderly, and I ended up using some Dlink tools I
found through Google to get my card slightly upgraded, but it seemed
to do the trick. The other Lucent/Orinoco card I had was more simple
and done in a few minutes.
> The error writing packet to BAP error always seemed just like a small
> nuisance to me during large file transfers. It did not correlate with
> any connectivity problems, so I just commented it out in the
> orinoco/hermes/orinoco_cs source (it's in one of those files.)
>
I never got to try it on large files, I had a few dozen errors from a
card idling with no connectivity :)
> Hope your wireless endeavors succeed - I just spent all week getting
> hostap_plx to work (and I'm now reaping the benefits because I now have
> wifi access all over my house) :)
>
Any benefit of using an AP over an ad-hoc network if it's only two or
three nodes in a room?
> Regards
> -Josh
>
mvh,
A
--
Alexander Hoogerhuis | [email protected]
CCNP - CCDP - MCNE - CCSE | +47 908 21 485
"You have zero privacy anyway. Get over it." --Scott McNealy
> Any benefit of using an AP over an ad-hoc network if it's only two or
> three nodes in a room?
Well, the benefit of an AP is slightly more symmetrical and wide
coverage(I _____think_____ - someone PLEASE correct me because I'm quite
unsure) and the range of an ad-hoc network is dependent on the number of
nodes.
So in, like, a living room, Ad-Hoc is probably just as good as using an
AP. But there's really no real advantage between the two. In my
experience using Ad-Hoc I have gotten faster TX rates, mostly because
there's no middle-man.
Still, it's up to you. If you were planning to shell out for an AP I
suggest you just set up a lowend Linux box with hostap driver
(http://hostap.epitest.fi) and use that (add iptables for internet
access, or whatever you like). cheaper and in some cases better.
Regards
-Josh
Rabid cheeseburgers forced Alexander Hoogerhuis<[email protected]> to
write this on 31 Dec 2002 06:44:16+0100:
> "Joshua M. Kwan" <[email protected]> writes:
>
> > > Warning: Driver for device eth1 has been compiled with version 14
> > > of Wireless Extension, while this program is using version 13.
> > > Some things may be broken...
> >
> > First of all, what kernel are you using? That's an ancient version
> > of the WE. If this is 2.4.2[01], download the following diffs from
> > Jean's fine site:
> >
> > *
> > http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw240_we15-6.diff
> > *
> > http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw241_we16-3.diff
> >
>
> No warnings anymore, and it all works. I now have a full 2 yards of
> wireless netowrk and dont have to run a cat5 over to muy couch :)
>
> Apart from that, Jean Tourrilhes' site was a treasure of HOWTOs and
> FAQs, so I'll spend a lot of time reading up there. Next thing up is
> bluetooth, and the site seems to be the right place for that, too.
>
> > Next of all, try upgrading the firmware on your card.
> >
>
> Went trough the motions of finding NetGears support on this. NetGear
> now officially has landed on my list of gear not to recommend. The
> while sitiation on finding firmware and tools to flash it didn't
> strike me as very orderly, and I ended up using some Dlink tools I
> found through Google to get my card slightly upgraded, but it seemed
> to do the trick. The other Lucent/Orinoco card I had was more simple
> and done in a few minutes.
>
> > The error writing packet to BAP error always seemed just like a
> > small nuisance to me during large file transfers. It did not
> > correlate with any connectivity problems, so I just commented it out
> > in the orinoco/hermes/orinoco_cs source (it's in one of those
> > files.)
> >
>
> I never got to try it on large files, I had a few dozen errors from a
> card idling with no connectivity :)
>
> > Hope your wireless endeavors succeed - I just spent all week getting
> > hostap_plx to work (and I'm now reaping the benefits because I now
> > have wifi access all over my house) :)
> >
>
> Any benefit of using an AP over an ad-hoc network if it's only two or
> three nodes in a room?
>
> > Regards
> > -Josh
> >
>
> mvh,
> A
> --
> Alexander Hoogerhuis | [email protected]
> CCNP - CCDP - MCNE - CCSE | +47 908 21 485
> "You have zero privacy anyway. Get over it." --Scott McNealy
>
--
Joshua Kwan
[email protected]
pgp public key at http://joshk.mspencer.net/pubkey_gpg.asc
Much of the excitement we get out of our work is that we don't really
know what we are doing.
-- E. Dijkstra