Linux-Development-Sys Digest #772, Volume #7 Sat, 15 Apr 00 10:13:18 EDT
Contents:
Re: high resolution timers ??? (Robert Redelmeier)
Re: Serial-only Linux box problems ("Lee M. Greiner Jr.")
Re: TCP-IP Stack Question ("Mark Graybill")
Re: pthread help!!! ("Mark Graybill")
Re: Problem with glibc v2.1.3 and _xstat. (A Guy Called Tyketto)
Re: 2.3.99-4-2: Kernel panic: VFS: Unable to mount root fs on .... (Christian
=?iso-8859-1?Q?J=F6nsson?=)
Re: Q: is there a free secure network filesystem for Linux? (Mario Klebsch)
Re: Drivers for newer HP printers? (Josh Rovero)
Re: To core or not to core - You tell me (Mark McIntyre)
Re: To core or not to core - You tell me (Mark McIntyre)
GAMES/TOYS(REQ)FROM COMP+INVENT ("gamesplayuk")
Re: How to debug driver that freezes the system? (M Sweger)
New to kernel programming - problem ([EMAIL PROTECTED])
----------------------------------------------------------------------------
From: Robert Redelmeier <[EMAIL PROTECTED]>
Subject: Re: high resolution timers ???
Date: Fri, 14 Apr 2000 23:32:54 -0500
Badrinath Venkatachari wrote:
>
> Hi,
> I have this mechanism in the kernel where I Q up read requests when
> they
> come in and make the processes that issued the requests sleep on a
> wait_queue. Then the idea is to have a timer driven function dQ them at
> regular intervals, issue the requests dQed and wake up the processes
> waiting for the request servicing.
>
> Currently, I have this timer getting woken up at millisecond precision
> (basically using jiffies with add_timer()). I would however, like to use
> a
> higher resolution timer for this purpose (microseconds). Is there one
> available ???
Yes, on the PC there is a Programmable Interrupt Timer living
on certain IO ports that you can use to generate interrupts.
IIRC, it runs at 1.19 MHz. In general, though, I would think
the easiest thing is just to adjust HZ from the x86 default of
100 up to 1000 or even 10,000. Alphas run at 1000, so software
should be variable HZ aware.
-- Robert
------------------------------
From: "Lee M. Greiner Jr." <[EMAIL PROTECTED]>
Crossposted-To: comp.os.linux.questions,comp.os.linux.misc,comp.os.linux.development
Subject: Re: Serial-only Linux box problems
Date: Sat, 15 Apr 2000 04:51:08 GMT
1) You do need to recompile the kernel to allow for serial console. Using a
serial cable with a null modem I am able to connect a serial port from a PC
to the serial port of my my Linux firewall. I receive lilo output, console
messages during boot and console login. Your serial statement in lilo.conf
is correct.
2) You will get a console login by putting "S1:23:respawn:/sbin/getty ttyS1
DT9600 vt100" in /etc/inittab. Don't
forget to remove /etc/ioctl.save. Do a man on login for configuring the
serial port to allow root login. I do not allow root login from console.
3) It does not matter whether you have a video card installed.
4) Lilo is limited to 38400 but the console login can be at least 115200( I
have not tried higher ). I believe you need at least a 16550A for speeds
above 19200. Add the following to /etc/gettydefs for 115200:
# 115200 fixed baud Dumb Terminal entry
DT115200# B115200 CS8 CLOCAL CRTSCTS # B115200 SANE -ISTRIP CLOCAL CRTSCTS
#@S login: #DT115200
You need XON/XOFF flow control.
>From the statements in your email I assume you have read serial-console.txt.
If not, it provides relevant info.
Good luck!
"Dave Newton" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> Hi,
>
> I'm currently working with RedHat 6.0 (product requirement for now),
> kernel vesion 2.2.5-15 (same). I've recompiled the kernel to allow for a
> serial console.
>
> My lilo.conf file has a "serial=1,9600n8" line in the 'global' section
> and a 'append="console=ttyS1,9600"' line in the kernel section (of the
> kernel in question).
>
> Here's my questions:
>
> 1) I'm not getting any input from the serial terminal. Is this a kernel
> or configuration issue? The serial cable should be good as I have had it
> successfully running getty. (It isn't now.)
> 2) Should I or should I not be getting the console login prompt on my
> serial terminal? I thought I should. Is a serial console only good for
> the console messages but not the console login? Is there another way to
> get this to work properly (i.e., perhaps my modifying /etc/inittab to
> run mingetty on the serial port in question)? I also need to have root
> be able to log on over the serial port, but I remember seeing something
> about that a long time ago WRT telnet root access.
> 3) Is the answer to #2 dependant on whether or not there is a VGA card
> in the system? (I have tried it with or without; I never get a console
> login prompt on the serial terminal.)
> 4) Am I truly limited to 9600 baud? I really need 57600 due to system
> constraints. Is this because it's using the PC BIOS serial routines? If
> so, if I have serial port routines in the BIOS that allow greater rates
> can I hack the kernel source to allow the higher speeds?
>
> Thanks much,
> Dave Newton
------------------------------
Reply-To: "Mark Graybill" <[EMAIL PROTECTED]>
From: "Mark Graybill" <[EMAIL PROTECTED]>
Crossposted-To:
alt.os.linux,alt.os.linux.mandrake,alt.os.linux.slackware,comp.os.linux.help,comp.os.linux.networking
Subject: Re: TCP-IP Stack Question
Date: Sat, 15 Apr 2000 05:55:00 GMT
BTW, I forgot to mention an important problem with multithreading on Windows
NT that Linux doesn't have.
Every Windows thread - that's EVERY Windows thread, when created, must call
each and every single DLL main of each and every single DLL loaded by the
owning process. The real kicker is that it is an atomic procedure. IOW,
only one at a time. This is why you cannot start a thread from DLLMAin.
The trick is to device a threading manager that creates a pool of suspended
threads on initialization, and when you need a thread, you simply give it a
pointer to your business code and tell it to resume.
-Mark
------------------------------
Reply-To: "Mark Graybill" <[EMAIL PROTECTED]>
From: "Mark Graybill" <[EMAIL PROTECTED]>
Crossposted-To: linux.dev.c-programming
Subject: Re: pthread help!!!
Date: Sat, 15 Apr 2000 05:58:08 GMT
I have a C++ package (library) that I am porting to Linux. It was written
with porting in mind by following ANSI C++, and isolating platform specific
API calls (like Win32 thread API calls.) It is a threading manager designed
to hide much of the threading tasks. It supports creating suspended as well
as thread pooling, global access (singleton), mass shutdown, etc.
Michael A Uman wrote in message <[EMAIL PROTECTED]>...
>Hello,
>
>Does anyone know if there is a way to spawn a thread which is
>'suspended' in the sense that Win32 has Suspended threads which can be
>resumed? I am trying to port a library which is currently supported on
>Win32 and Macintosh.
>
------------------------------
From: A Guy Called Tyketto <[EMAIL PROTECTED]>
Subject: Re: Problem with glibc v2.1.3 and _xstat.
Crossposted-To: comp.os.linux.development,comp.os.linux.development.apps
Date: Sat, 15 Apr 2000 07:26:19 GMT
=====BEGIN PGP SIGNED MESSAGE=====
Hash: SHA1
In comp.os.linux.development.apps Peter Chapin <[EMAIL PROTECTED]> wrote:
> When Apache loads it complains that it can't load the php support
> library (a .so file) and exits. The reason: "unresolved symbol _xstat".
> My workaround is to disable php support for now.
> I remember reading something about this _xstat issue in one of the
> documents I reviewed before doing this installation. However, I can't
> seem to locate that information now. It's not in the FAQ and it's not in
> the INSTALL file. I just don't know where I saw it. Does anyone know
> what the story is with _xstat and glibc v2.1.3?
> TIA
> Peter
From the GLIBC FAQ, at
http://www.gnu.org/software/libc/glibc-FAQ.html:
17. ``Looking through the shared libc file I haven't found the
functions `stat', `lstat', `fstat', and `mknod' and while linking on
my Linux system I get error messages. How is this supposed to work?''
{RM} Believe it or not, stat and lstat (and fstat, and mknod) are
supposed to be undefined references in libc.so.6! Your problem is
probably a missing or incorrect /usr/lib/libc.so file; note that this
is a small text file now, not a symlink to libc.so.6. It should look
something like this:
GROUP ( libc.so.6 ld.so.1 libc.a )
or in ix86/Linux and alpha/Linux:
GROUP ( libc.so.6 ld-linux.so.2 libc.a )
This does also include _xstat. Try recompiling Apache, and you
should be good to go. Don't forget to recompile the module as well.
BL.
- --
Brad Littlejohn | Email: [EMAIL PROTECTED]
Unix Systems Administrator, | [EMAIL PROTECTED]
Web + NewsMaster, BOFH.. Smeghead! :) | http://www.wizard.com/~tyketto
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------------------------------
From: Christian =?iso-8859-1?Q?J=F6nsson?= <[EMAIL PROTECTED]>
Crossposted-To: linux.dev.kernel
Subject: Re: 2.3.99-4-2: Kernel panic: VFS: Unable to mount root fs on ....
Date: Sat, 15 Apr 2000 08:31:42 GMT
strange, now I got the 2.3.99-pre6-pre3 running, I'm not quite sure what I
changed but perhaps it is #CONFIG_PARTITION_ADVANCED is not set
that was set before...
Anyway, it's working now...
/ChJ
"Christian J�nsson" wrote:
> sure, but I don't seem to be able to config 2.3.99-preX kernels
> to handle my IDE disk... :-( things have changed here and I haven't
> tried to go down that lane to make it work again.
>
> Cheers,
>
> /ChJ
>
> "Mario Klebsch" <[EMAIL PROTECTED]> skrev i meddelandet
> news:[EMAIL PROTECTED]...
> > Ivan De Saedeleer <[EMAIL PROTECTED]> writes:
> >
> > >In linux.dev.kernel Christian J�nsson <[EMAIL PROTECTED]>
> wrote:
> > >> VFS: Mounted root (ext2 filesystem).
> > >> kmod: failed to exec /sbin/modprobe -s -k block-major-3, errno = 2
> > >> VFS: Cannot open root device "306" or "03:06"
> > >> Please append a correct "root=" boot option
> > >> Kernel panic: VFS: Unable to mount root fs on 03:06.
> >
> > >Same problem here, i don't have found the solution yet...
> >
> > The sollution is obvious:
> >
> > >> kmod: failed to exec /sbin/modprobe -s -k block-major-3, errno = 2
> > ^^^^^^^^ ^^^^^^^^^^^^^
> > The Kernel tries to load the driver for block device major number
> > 3. Why? see later...
> >
> > >> VFS: Cannot open root device "306" or "03:06"
> > ^^
> > It expects its root filesystem on block device with major number 3. To
> > access the filesystem on this device, the kernel needs ... the driver
> > for block device major number 3.
> >
> > The sollution is to include the driver for block device major number 3
> > into the kernel. Alternatively, you can include this driver on your
> > initial ramdisk. In this case, you also have to include /sbin/modprobe
> > and /etc/conf.modules. Block device majro 3 is the IDE hard disk
> > driver (on my system).
> >
> > 73, Mario
> > --
> > Mario Klebsch [EMAIL PROTECTED]
------------------------------
From: [EMAIL PROTECTED] (Mario Klebsch)
Subject: Re: Q: is there a free secure network filesystem for Linux?
Date: Sat, 15 Apr 2000 11:36:07 +0200
[EMAIL PROTECTED] writes:
>Michael Pronath <[EMAIL PROTECTED]> wrote:
>: Is there a network filesystem, that has useful security features (i.e. not
>: NFS), and is free and open source available for Linux (i.e. not AFS) ?
>: What would you use for a small LAN, Home Office or so? Samba?
>NFS over Secure RPC is a possibility. We have used it
>here successfully to tunnel NFS over long distances (the
>NFS traffic travels inside an SSH TCP tunnel).
Please correct me, if I am wrong, but secure NFS is NOT NFS over SSH.
>However, this is still only really useful if you trust the
>kernel on the client end (ie. it doesn't change the basic
>insecurity of NFS - just allows you to send it over the
>Internet with fewer worries).
AFAIK, this is one of the main benefits of secure NFS. It is no longer
required to trust the kernel on the client side. However, I never used
secure NFS when I worked with Solaris systems, since I did trust my
clients.
73, Mario
--
Mario Klebsch [EMAIL PROTECTED]
------------------------------
From: Josh Rovero <[EMAIL PROTECTED]>
Subject: Re: Drivers for newer HP printers?
Date: Sat, 15 Apr 2000 07:46:50 -0400
Paul McGaughey wrote:
>
> Anyone know if there are drivers available for some of the newer HP printers?
> In particular, I am looking for something that will work with a DeskJet 952C, (the
>DeskJet 950 series).
The latest RH 6.2 includes "PPA" printer driver, which is
meant to support the typical "works with windows" el-cheapo
printers.
Haven't tried it, but it's there.
--
P. Josh Rovero email: [EMAIL PROTECTED]
web: http://www.connix.com/~provero
------------------------------
From: Mark McIntyre <[EMAIL PROTECTED]>
Crossposted-To: comp.lang.c,comp.unix.solaris,comp.lang.c++,comp.unix.programmer
Subject: Re: To core or not to core - You tell me
Date: Sat, 15 Apr 2000 13:00:20 +0100
Reply-To: [EMAIL PROTECTED]
On Sat, 15 Apr 2000 01:47:00 GMT, [EMAIL PROTECTED] (Kaz
Kylheku) wrote:
>On Fri, 14 Apr 2000 23:27:07 +0100, Mark McIntyre <[EMAIL PROTECTED]>
>wrote:
>>On Fri, 14 Apr 2000 01:02:17 GMT, [EMAIL PROTECTED] (Kaz
>>Kylheku) wrote:
>>
>>>On Fri, 14 Apr 2000 00:08:23 +0100, Mark McIntyre <[EMAIL PROTECTED]>
>>>wrote:
>>>>On Wed, 12 Apr 2000 15:33:17 -0700, Erik Max Francis <[EMAIL PROTECTED]>
>>>>wrote:
>>>>
>>>>>Mark McIntyre wrote:
>>>>>
>>>>>> Agreed. I'm talking about NULL, the macro which 6.3.2.3 and 7.17 in
>>>>>> the ANSI/ISO C standard defines as the null pointer constant.
>>>>>
>>>>>But you said "the bit pattern of NULL," which doesn't make sense,
>>>>>because NULL is a macro. Macros don't have bit patterns.
>>>>
>>>>But the macro preprocesses out to a value. And that value is either an
>>>>integer 0 or such an expression cast to a void*. This value is
>>>>represented in memory by some bitpattern.
>>>
>>>Read my other posting about this. The value of an expression is not
>>>necessarily represented in memory.
>>
>>Uhh, we had this discussion a few months back. No matter what,
>>eventually it _has_ to be in memory somewhere, even if its only in a
>>register. The processor cannot use it unless it exists somewhere...
>
>A register is not ordinary memory; that is to say, it is not considered
>to be storage, in the sense of the term as used in the C standard.
I'm not sure htat the C standard cares about memory representations or
otherwise. Remember its independent of hardware. But you know that
better than I do so we almost certainly have no disagreement here.
>>>That is why an expression like:
>>>
>>> &3
>>>
>>>is invalid. An expression that is not an l-value doesn't refer to an object.
>>>In the abstract semantics of C, it is a data object which has a representation.
>>>Something that is not a data object doesn't have a representation.
>>
>>Thats more to do with it being an addressless item. IIRC the point is
>>that a literal may be stored in a register or other form of
>>nonaddressable memory.
>
>If it's non-addressable, it's not a data object. My example at the end of the
>posting shows that a literal doesn't have to be stored anywhere at all. E.g. a
>comparison against a constant zero may produce an implicit ``test for zero and
>branch'' instruction that doesn't have a zero stored anywhere in its opcode.
Of course. However ahem, zero is almost certainly a very very special
case.
Mark McIntyre
C- FAQ: http://www.eskimo.com/~scs/C-faq/top.html
------------------------------
From: Mark McIntyre <[EMAIL PROTECTED]>
Crossposted-To: comp.lang.c,comp.unix.solaris,comp.lang.c++,comp.unix.programmer
Subject: Re: To core or not to core - You tell me
Date: Sat, 15 Apr 2000 12:58:25 +0100
Reply-To: [EMAIL PROTECTED]
On Fri, 14 Apr 2000 18:23:26 -0700, Erik Max Francis <[EMAIL PROTECTED]>
wrote:
>Mark McIntyre wrote:
>
>> Erik Max Francis wrote:
>>
>> >Hence the problem; it is perfectly legal for NULL to be defined as 0,
>>
>> yup.
>>
>> >which in and of itself is not a pointer.
>>
>> says who?
>
>It's defined as a null pointer constant.
what, zero is defined as a null pointer constant? ROTFL.
ITYM the other way round...
>A null pointer constant isn't
>what you were talking about either; you were talking about the internal
>representation of the null pointer itself.
I find this highly amusing. I have told you that I'm talking about
NULL. So stop trying to twist the conversation to your own topic.
>> > So it makes little sense to
>> > talk about the "bit pattern of NULL"; what you mean is the bit
>> > pattern
>> > of the null pointer.
constant.
>> *sigh*. No I don't I mean the bit pattern of the value that NULL
>> preprocesses out into when the preprocessor runs through your code.
>> You are the one talking about a null pointer. I'm talking about the
>> null pointer constant.
>
>There is no _the_ null pointer constant; a null pointer constant is
>either 0 or (void *) 0. NULL can be defined as 0 -- that is completely
>legitimate. In that case, int null = NULL would be legal code and would
>not represent a null pointer. So you can't mean the internal
>representation of NULL _or_ a null pointer constant. It's the null
>pointer itself that you're talking about.
have you been listening to ANY of this thread? The entire debate is
about NULL aka the null pointer constant aka 0 or (void*)0. Thats what
the entire discussion is about.
>The null pointer is what you're talking about, not a null pointer
>constant, and not the NULL macro.
No its not. If you say this once more I will be very very cross. Stop
it.
Mark McIntyre
C- FAQ: http://www.eskimo.com/~scs/C-faq/top.html
------------------------------
From: "gamesplayuk" <[EMAIL PROTECTED]>
Subject: GAMES/TOYS(REQ)FROM COMP+INVENT
Date: Sat, 15 Apr 2000 13:56:11 +0100
Companies of Games + Toys are you looking for new markets?
Invnetors seeking help?
Please visit our web site its a must
www.gamesplayuk.co.uk
------------------------------
From: [EMAIL PROTECTED] (M Sweger)
Subject: Re: How to debug driver that freezes the system?
Date: 15 Apr 2000 13:38:30 GMT
Reply-To: [EMAIL PROTECTED]
: clear_bit() expands into one assembly instruction. Anybody know why it
: would cause the computer to lock up? I'm using a Dell latitude 133Mhz
: P2 with Linux v2.2.13
Is it a legal instruction for you intel microprocessor chipset?? i.ie. 485 vs.
686.
--
Mike,
[EMAIL PROTECTED]
------------------------------
From: [EMAIL PROTECTED]
Subject: New to kernel programming - problem
Date: Sat, 15 Apr 2000 15:49:46 +0000
Hi. I want to write a kernel module and access the kernel task
structures from within the module but
I've got some problems doing this :
In /usr/src/linux/kernel/sched.c you can find:
struct task_struct * task [NR_TASKS] = {&init_task, };
when I write a kernel module which uses the task array, insmod tells me
that it can't resolve the module : "task".
You know how to solve this problem? Please write to
[EMAIL PROTECTED]
Thanks a lot!!
------------------------------
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