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 Posted: Thu Jun 26, 2003 3:33 pm Post subject: irq handling- kernel vs. user code |
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Larry Doolittle
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| Posted: Thu Jun 26, 2003 3:33 pm Post subject: Re: irq handling- kernel vs. user code |
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In article <vDfKa.25563$uK1.23826@fe05.atl2.webusenet.com>, Neil Horman wrote:
| Quote: | I would suggest that you implement a socket family to produce
this mechanism.
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When I needed this kind of functionality (transferring hardware
events to user space) I simply made a kernel driver for a /dev/pulse
character special device (Major device 10, minor device selected
from 240-255 "Reserved for local use"). It wasn't hard to grab
code from the Rubini book and drivers/char/nwbutton.c and make
something that works. Sounds simpler than inventing a whole new
socket family.
- Larry |
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Alex Pavloff
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| Posted: Thu Jun 26, 2003 10:06 pm Post subject: Re: maybe a little OT: CF-Card not available in XP |
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On Thu, 26 Jun 2003 08:36:18 GMT, Jens Nixdorf <usenet@embesso.com>
wrote:
| Quote: | I think, my system is too big for a loop-system (because X is that big).
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I don't think there's a limit on the size of a loop system. I run X
(ok, TinyX) in mine with a 20 meg image on a 32 meg flash. The loop
just is a blank file -- and then the inside gets formatted as, say,
ext2. Then you mount the main system image as RO to prevent
accidental writes.
Then you use a smaller image as a ramdisk with some startup files in
it. SYSLINUX or LOADLIN loads Linux from the ramdisk, which then
does the root pivot thing and loads up the image.
| Quote: | But that brings me to another idea: How is it with UMSDOS? Normally the
linux-files are startet only once, then the application, after this
nothing has to be started. Only the logfiles will be written. Anyone
experienced with this?
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I tried UMSDOS. It didn't work very well.
1) The filenames in DOS are still 8.3
2) It seemed to lose files
It just sucked overall.
--
Alex Pavloff - remove BLAH to email
Software Engineer, Eason Technology |
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Neil Horman
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| Posted: Thu Jun 26, 2003 10:20 pm Post subject: Re: irq handling- kernel vs. user code |
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Larry Doolittle wrote:
| Quote: | In article <vDfKa.25563$uK1.23826@fe05.atl2.webusenet.com>, Neil Horman wrote:
I would suggest that you implement a socket family to produce
this mechanism.
When I needed this kind of functionality (transferring hardware
events to user space) I simply made a kernel driver for a /dev/pulse
character special device (Major device 10, minor device selected
from 240-255 "Reserved for local use"). It wasn't hard to grab
code from the Rubini book and drivers/char/nwbutton.c and make
something that works. Sounds simpler than inventing a whole new
socket family.
- Larry
I've used the character driver method as well, and it is actually a bit |
simpler to implement. I chose to use the socket interface primarily
becuase I typically write device drivers for various networking devices
(switch fabrics, nP's, etc.) and on interrupt I receive control data as
a packet. The socket family in my case was the more intuative design.
Sorry, probably should have thought of that before I posted.
Neil |
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Bernhard Roessmann
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| Posted: Thu Jun 26, 2003 11:44 pm Post subject: Re: hard disk benchmark |
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Alpinekid wrote:
| Quote: | Hi,
What would be a good benchmark program for evaluating harddisk
performance. I'm using RH8.0 right now and want to check the IDE
hardrive performance on verious setups and hardware.
Al
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hdparm -t
--
Bernhard Roessmann
Don't Fear The Penguins! |
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Alpinekid
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| Posted: Fri Jun 27, 2003 1:05 am Post subject: Re: hard disk benchmark |
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Bernhard Roessmann wrote:
| Quote: | Alpinekid wrote:
Hi,
What would be a good benchmark program for evaluating harddisk
performance. I'm using RH8.0 right now and want to check the IDE
hardrive performance on verious setups and hardware.
Al
hdparm -t
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thanks,
Al |
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Damion de Soto
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| Posted: Fri Jun 27, 2003 4:41 am Post subject: Re: problem with PCI to USB card |
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Shih-Ying Chou wrote:
| Quote: | Hi,
I am trying to build a fingerprint module with Embedded Planet's
ep405 board and Timesys Linux distribution(Kernel version 2.4.7).
Does the ep405 have a bios to initialise the card on the pci bus ?
There is no bios for the ep405 development board
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If the board does not have a bios to initialise the pci card/bus, the
kernel will have to do it.
| Quote: | Is the PCI USB card identified in the kernel boot-up messages?
No, the kernel does not identified the PCI USB card at boot-up.
Also, there is no information about the card appears in the /proc/pci
file.
Which direction should I look at, PCI or USB?
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the PCI bus needs to be setup and the USB card found before you'll be
able to use the drivers for it.
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Damion de Soto - Software Engineer email: damion@snapgear.com
SnapGear --- ph: +61 7 3435 2809
| Custom Embedded Solutions fax: +61 7 3891 3630
| and Security Appliances web: http://www.snapgear.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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Jens Nixdorf
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| Posted: Fri Jun 27, 2003 1:55 pm Post subject: Re: maybe a little OT: CF-Card not available in XP |
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Am Thu, 26 Jun 2003 17:06:52 GMT schrieb Alex Pavloff :
| Quote: | I don't think there's a limit on the size of a loop system. I run X
(ok, TinyX) in mine with a 20 meg image on a 32 meg flash. The loop
just is a blank file -- and then the inside gets formatted as, say,
ext2. Then you mount the main system image as RO to prevent
accidental writes.
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There is not really a limit by concept, but my customer is setting my
limits. I have a 128MB-CF-card, 75-80 MB are used by linux, 15 MB by the
application with all the graphics, other 15-20 MB has to be spared for
logs. So i get no room anymore.
[...UMSDOS]
| Quote: | It just sucked overall.
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OK, this idea is dead ;)
regards, Jens
--
Die obige Adresse ist OK, wird aber nicht gelesen.
Für Mails an mich bitte das Wort "usenet" gegen
"jens.nixdorf" austauschen. |
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nikhil bhargav
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| Posted: Fri Jun 27, 2003 2:44 pm Post subject: Re: customizing bootloader |
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"August Hörandl" <august.hoerandl@gmx.at> wrote in message news:<m3llvq7ixc.fsf.gustl@gmx.at>...
| Quote: | nikhilbhargav_nsit@indiatimes.com (nikhil bhargav) writes:
We have our own inhouse customized board based on mbx 860 from
motorola. We have its initialization file and the board is properly
initialized as I have been able to flash ppc boot (binary for std
mbx860) in it using BDI2000. Now we need to customize the bootloader
ppcboot or redboot as per this board. Has anyone didthis job before. I
yes ;-)
am reading the source code of ppcboot and its really big. Can some
experienced in it give me pointer as to where we should start and how.
get u-boot which ist ppcboot the next generation - the README has got
a brief introduction "howto port to a new board" (the source is big,
but you have to do little changes, just few files to add/change)
subscribe to the u-boot mailing list - thats the place to get help
hth
Gustl
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Hello Gustl,
Thanks for your advice. I have done that now. If you know any other
pointer than do let me know.
bye,
nikhil |
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Dave Hansen
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| Posted: Fri Jun 27, 2003 8:01 pm Post subject: Re: Floating point format for Intel math coprocessors |
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On Fri, 27 Jun 2003 14:23:22 GMT, Jack Crenshaw <jcrens@earthlink.net>
wrote:
| Quote: | I've run across a peculiarity concerning the format used inside the
Intel math coprocessor. I have always
thought that the format used was in accordance with the IEEE 794
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Unless IEEE 794 is something new, I think you mean IEEE 754.
| Quote: | standard, and every reference I've seen
on the web seems to imply that. But, as nearly as I can tell, it's not
the same.
The IEEE standard for 32-bit floats says the format should be
sign -- 1 bit
exponent -- 8 bits, power of 2, split on 127
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With the proviso that the values of 0 and 255 for the exponent are
special cases reserved for 0, Inf, denormals, and NaN.
| Quote: | mantissa -- 23 bits + phantom bit in bit 24.
The Intel processor seems to use the following:
sign -- 1 bit
exponent -- _SEVEN_ bits, power of _FOUR_
mantissa -- sometimes 23 bits, sometimes 24. Sometimes phantom bit,
sometimes not.
When it's there, it's in bit _TWENTY_THREE_ <!
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I don't think so. Are you mistaking the lsb of the exponent for the
"visible" phantom bit?
[...]
| Quote: |
You'll see that 1 --> 3f800000 (high bit is visible)
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seee eeee emmm mmmm mmmm mmmm mmmm mmmm
0011 1111 1000 0000 0000 0000 0000 0000
s = 0, e = 127, m = 0
(-1)^s * 2^(e-127) * (1+m/(2^23)) = 1*1*1 = 1.0
| Quote: | but 2 --> 40000000 (high bit is not)
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seee eeee emmm mmmm mmmm mmmm mmmm mmmm
0100 0000 0000 0000 0000 0000 0000 0000
s = 0, e = 128, m = 0
(-1)^s * 2^(e-127) * (1+m/(2^23)) = 1*2*1 = 2.0
| Quote: |
Try a few others and see what you get. Some will surprise you.
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I'm not finding any surprises.
1.5 -> 3fc00000
seee eeee emmm mmmm mmmm mmmm mmmm mmmm
0011 1111 1100 0000 0000 0000 0000 0000
s = 0, e = 127, m = 0x400000
(-1)^s * 2^(e-127) * (1+m/(2^23)) = 1*1*1.5 = 1.5
2.5 -> 40200000
seee eeee emmm mmmm mmmm mmmm mmmm mmmm
0100 0000 0020 0000 0000 0000 0000 0000
s = 0, e = 128, m = 0x400000
(-1)^s * 2^(e-127) * (1+m/(2^23)) = 1*2*1.25 = 2.5
Perhaps I'm misunderstanding your point?
Regards,
-=Dave
--
Change is inevitable, progress is not. |
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Grant Edwards
Guest
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| Posted: Fri Jun 27, 2003 8:34 pm Post subject: Re: Floating point format for Intel math coprocessors |
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In article <3EFC53CF.76D1DAAF@earthlink.net>, Jack Crenshaw wrote:
| Quote: | I've run across a peculiarity concerning the format used inside
the Intel math coprocessor.
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If you're talking about the format that IA32 FPs store values
in memory, then I doubt it. If you're talking about the 80-bit
internal format, I don't know. I've never tried to use that
format externally.
I've been exchanging float data between IA32 systems and at
least a half-dozen other architectures since the 8086/8087
days. I never saw any format problems.
| Quote: | I have always thought that the format used was in accordance
with the IEEE 794 standard,
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It is IEEE <something> though 794 doesn't sound right...
--
Grant Edwards grante Yow! .. this must be what
at it's like to be a COLLEGE
visi.com GRADUATE!! |
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G. Remlin
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| Posted: Fri Jun 27, 2003 8:59 pm Post subject: Re: RTLinux Project Dead? |
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Marc Briand wrote:
| Quote: | I just read Karim Yaghmour's article on oreillynet
http://linux.oreillynet.com/pub/a/linux/2003/06/09/embedlinux.html> in
which he says,
"At the time of this writing, the RTLinux project is practically dead
and none of the those working on the commercial offerings of FSMLabs,
the company founded by RTLinux's creator to market RTLinux, is actively
contributing new open source RTLinux code, or helping users on the
RTLinux mailing list."
I was wondering if anyone on this group had an opinion about this. I am
considering getting involved in an RTLinux project and I find this
article fairly disturbing.
Thanks,
Marc
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At the bottom of the article, the author is identified:
"the founder and president of Opersys Inc."
Unbiased? Has a financial interest in the death of RTLinux?
Regards,
George |
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Robert Kaiser
Guest
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| Posted: Fri Jun 27, 2003 9:04 pm Post subject: Re: RTLinux Project Dead? |
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In article <3EFC72C4.DB039CC6@sunflower.com>,
Marc Briand <marcbriand@sunflower.com> writes:
| Quote: | "At the time of this writing, the RTLinux project is practically dead
and none of the those working on the commercial offerings of FSMLabs,
the company founded by RTLinux's creator to market RTLinux, is actively
contributing new open source RTLinux code, or helping users on the
RTLinux mailing list."
I was wondering if anyone on this group had an opinion about this. I am
considering getting involved in an RTLinux project and I find this
article fairly disturbing.
|
If the RTLinux project is really dead, that doesn't necessarily
mean real-time Linux is dead. The RTAI project is alive and well
and, from what I hear, it seems to be a better alternative anyway.
If you are just about to get involved (i.e. you do not have any
RTLinux legacy to deal with), then why choose RTLinux over RTAI?
Rob
--
Robert Kaiser email: rkaiser AT sysgo DOT de
SYSGO AG http://www.elinos.com
Klein-Winternheim / Germany http://www.sysgo.de |
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CBFalconer
Guest
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| Posted: Fri Jun 27, 2003 10:28 pm Post subject: Re: Floating point format for Intel math coprocessors |
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Jack Crenshaw wrote:
| Quote: |
.... snip ...
The IEEE standard for 32-bit floats says the format should be
sign -- 1 bit
exponent -- 8 bits, power of 2, split on 127
mantissa -- 23 bits + phantom bit in bit 24.
The Intel processor seems to use the following:
sign -- 1 bit
exponent -- _SEVEN_ bits, power of _FOUR_
mantissa -- sometimes 23 bits, sometimes 24. Sometimes
phantom bit, sometimes not. When it's there, it's in bit
_TWENTY_THREE_ <!
.... snip ...
You'll see that 1 --> 3f800000 (high bit is visible)
but 2 --> 40000000 (high bit is not)
Try a few others and see what you get. Some will surprise you.
I know that there must be people out there to whom this is old,
old news. Even so, I've never seen a word about it, and didn't
find anything in a Google search. I'd appreciate any comments.
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What chips does this format appear in? I expect the presence or
absence of normalization depends on the oddness of the exponent
byte. It makes sense for byte addressed memory based systems,
since zero (ignoring denormalization) can be detected in a single
byte.
--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address! |
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Herman Bruyninckx
Guest
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| Posted: Fri Jun 27, 2003 11:24 pm Post subject: Re: RTLinux Project Dead? |
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On Fri, 27 Jun 2003, Marc Briand wrote:
| Quote: | I just read Karim Yaghmour's article on oreillynet
http://linux.oreillynet.com/pub/a/linux/2003/06/09/embedlinux.html> in
which he says,
"At the time of this writing, the RTLinux project is practically dead
and none of the those working on the commercial offerings of FSMLabs,
the company founded by RTLinux's creator to market RTLinux, is actively
contributing new open source RTLinux code, or helping users on the
RTLinux mailing list."
I was wondering if anyone on this group had an opinion about this. I am
considering getting involved in an RTLinux project and I find this
article fairly disturbing.
IMHO, he refers to the fact that RTAI has a much better record of |
accepting contributions from anybody with a good patch.
Unconditionally, and without keeping a core of code with "undisturbed"
copyrights, in order to protect a product with a proprietary license.
While the RTlinux people are devoting the largest part of their
efforts on their closed cource RTLinux/PRO. So, RTLinux is not dead,
but has succeeded in scaring away quite some good and independent
developers. That does _not_ mean RTLinux/GPL is a bad or deprecated
product. Not at all. And RTLinux/PRO is certainly better supported
professionaly.
Herman
--
K.U.Leuven, Mechanical Engineering, Robotics Research Group
<http://people.mech.kuleuven.ac.be/~bruyninc> Tel: +32 16 322480 |
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