Subject: Linux-Development Digest #318
From: Digestifier <[email-masked]>
To: [email-masked]
Date: Sun, 16 Oct 94 17:13:15 EDT

Linux-Development Digest #318, Volume #2         Sun, 16 Oct 94 17:13:15 EDT

Contents:
  Linux filesystem layout (Jake Pusey)
  Re: IS anyone reading users' complaints? (root)
  Re: kstat.dk_drive isn't incremeneted (Nick Holloway)
  Re: WANTED: Xerion bin or ported source (Rafal Kustra)
  Making generic SCSI stuff work. (M. K. Shenk)
  Re: Making generic SCSI stuff work. (M. K. Shenk)
  Re: We a FAQ: Linux vs. *BSD!!! (Dan Yergeau)
  Re: Filesystem idea (Kai Petzke)
  Re: 1.1.53 - fdformat - IOCTL error still there (Andre Schoorl)
  Re: Mathematical functions with c (David Cure)
  Re: Optimizing the NFS server (Kevin Martinez)
  Re: Writing to OS/2 HPFS...how soon? (Martin Spott)
  Re: A badly missed feature in gcc (Jeff Kesselman)
  Re(2): Linux For Mac (Robert A. Piacente)
  Re: Improving SLIP latency under Linux (Matthew Dillon)

----------------------------------------------------------------------------

From: [email-masked] (Jake Pusey)
Crossposted-To: comp.os.linux.help
Subject: Linux filesystem layout
Date: 12 Oct 1994 17:45:29 GMT

    I need help on the layout of the linux filessytem.  I
know that the third block contains an inode bitmap, but
how many inodes does it represent?  I coudlnt get the
numbers to match dumpe2fs.

    Do the inodes begin at the start of the 4th block?
Please give me any info on inode, inodelist, and datablock
that you can spare.  I am getting frustrated by the
whole thing!!!:}

    Seriously, I would like to know how to decrypt
the inodes (I am taking a class in Unix systems programming)
so this is crucial.  Textual descriptions preferred, code is
okay but I don't want too much (have tolearn...).

  Any help is greatly appreciated.

Jake

------------------------------

From: [email-masked] (root)
Subject: Re: IS anyone reading users' complaints?
Date: 16 Oct 1994 19:41:42 GMT
Reply-To: [email-masked]

Perhaps there is a need for comp.os.linux.bugs? I should go check what
the reorganization RFC is saying.

------------------------------

From: [email-masked] (Nick Holloway)
Subject: Re: kstat.dk_drive isn't incremeneted
Date: Sun, 16 Oct 1994 00:36:04 +0000

In <[email-masked]> leisner@batman (Marty Leisner 25733) writes:
> I'm running procinfo, and the disk information isn't getting incremented...
> [...]
> Looking more carefully, it appears the 0are
> kstat.dk_drive[0-3] isn't being incremented anywhere...

They aren't.  They never have done (in a production kernel).  Randy
Appleton produced a patch that did this, but this would be unable to
distuinguish between hda and sda.  I believe that this was on sunsite
at some stage, and may still be.

I also wrote a patch that I sent to Linus and Linux Activists.  I would
expect it to be easily modified for the current kernel, despite it being
relative to 1.0.  Here it is if you (or anybody else) wants it.

-- 
Nick Holloway |  `O O'  | Home: [email-masked]
[aka `Alfie'] | // ^ \\ | Work: [email-masked]

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Here is a patch relative to v1.1.0

The placing of the code to do the collection for disk statistics came
from Randy Appleton's patch, but this uses a different approach.  His
approach had the disadvantage that hda and sda would be lumped together
-- probably not a too uncommon occurance.

This will collect statistics for drives in the order they are first
accessed.  It does this by keeping a table of drives.  Although this is
searched linearly there are only 4 entries.

It considers devices on the same drive as equivalent by munging the
device to strip out the sub-drive bits.  It should be done using MAJOR,
MINOR and MAKEDEV macros, but this doesn't get optimised into the form
used.

It currently collects statistics for hd, hd1, xd, sd, and fd.  It could
easily be extended to include CDROMS too.  I'm not sure of the worth of
collecting for floppy drives, but I've only got two hard disks, so it
helps fill up the table :-)

        Nick Holloway

--- 1.1 1994/04/08 16:29:46
+++ drivers/block/ll_rw_blk.c   1994/04/09 10:35:44
@@ -152,6 +152,48 @@
 static void add_request(struct blk_dev_struct * dev, struct request * req)
 {
        struct request * tmp;
+       static dev_t drivetbl[DK_NDRIVE];
+       dev_t drive = 0;
+       int i;
+
+       /* Disk usage statistics.
+        *   If we want statistics for a device, we fold it into a single
+        * drive, and update the statistics.  The drives are in the order
+        * we first see them.  I would expect this wouldn't change much on
+        * many systems -- possible exeception could be fd0 vs fd1.
+        *   We could keep drivetbl in kstat, and make it visible via /proc
+        * so that we can work out what the devices really are, but is this
+        * worth it?
+        *      Nick Holloway, 8th April 1994.
+        */
+       switch (MAJOR(req->dev)) {
+               case SCSI_DISK_MAJOR:
+                       drive = req->dev & 0xFFF0;
+                       break;
+               case HD_MAJOR:
+#ifdef HD1_MAJOR
+               case HD1_MAJOR:
+#endif
+               case XT_DISK_MAJOR:
+                       drive = req->dev & 0xFFC0;
+                       break;
+               case FLOPPY_MAJOR:
+                       drive = req->dev & 0xFF03;
+                       break;
+       }
+       if (drive != 0) {
+           for (i = 0; i < DK_NDRIVE; i++) {
+               if (drivetbl[i] == drive) {
+                   kstat.dk_drive[i]++;
+                   break;
+               } else if (drivetbl[i] == 0) {
+                   /* printk("kstat.dk_drive[%d] is drive %04x\n", i, drive); */
+                   drivetbl[i] = drive;
+                   kstat.dk_drive[i]++;
+                   break;
+               }
+           }
+       }
 
        req->next = NULL;
        cli();

------------------------------

From: [email-masked] (Rafal Kustra)
Subject: Re: WANTED: Xerion bin or ported source
Date: 14 Oct 94 21:05:09 GMT

>>>>> "Greg" == Greg Bruell <[email-masked]> writes:
In article <[email-masked]> [email-masked] (Greg Bruell) writes:

    Greg> I know this has been posted before but I couldn't remember
    Greg> when. If anyone has a working linux port of xerion binaries
    Greg> or source I would greatly appreciate them. This seems like a
    Greg> good thing to put on sunsite. I'm sure it would be accepted
    Greg> into Incoming and I don't think it would break any copying
    Greg> agreements. Thanks.

    Greg> Gregory Bruell Wellfleet Communications, Inc.

Funny, I just compiled xerion (which we use for assignement, here at
UofT), yesterday (actually today, since I finished at 2am). Compiles
without a hitch once you have tcl/tk installed with all extensions.
Only problem I had was when I compiled it DLL with new 3.1 Xlibs -
since tcl/tk is also DLL with 2.1.1 Xlibs. Solution was to use old
Xlibs.

I have the freshest sources, which fixed a bad memory leak, just few
days ago (so we could do an assignement in a course -:).

I will ask the guys in Neural Net whether its OK to upload it to
sunsite - copyright notice would indicate it would be no problem.

                        Rafal

------------------------------

From: [email-masked] (M. K. Shenk)
Subject: Making generic SCSI stuff work.
Date: 14 Oct 1994 11:59:11 GMT

A couple of folks wanted this.

Ok, if you've got SCSI devices that are not being seen on bootup, it's
because your device type does not have a case in a switch statement
in /usr/src/linux/drivers/scsi/scsi.c (or wherever it is for you.) and
the switch is defaulting and assigning a -1 to the variable 'type.'  The
quick and dirty fix would be to comment this out.   I personally am
setting up a scanner, and did this:  in scsi.h there are a bunch of
#defines for various types of SCSI devices.  I put in a #define TYPE_SCANNER
0x06 and then added an empty case in the switch so we wouldn't default.
Don't see any real reason not to add this #define to scsi.h in the standard
kernel...  I also had to do something you might also have to do:  my scanner
is a bit addled and responds to all LUNs when it is being detected.  The
fix for this problem, or your device hanging when polled for LUNs > 0, is
to give it an entry in the 'blacklist' in scsi.c, so it's only polled
for LUN 0.  Mine was {"UMAX", "UC840", "V1.4"}.  Search for 'blacklist'
it's pretty self-explanatory.  

Now-- major # for generic devices is 21 (a lot of folks will already have
entries /dev/sg[a-h] with major 21, minors 0-7) and the minor depends on
the device's RELATIVE position on the scsi bus...not it's id.  This will
also be the order of detection on bootup... Note that ALL scsi devices
will get an entry...tapes, disks, CD-ROMs, etc.  So someone with devices
on scsi id#1, 2, and 5 would have the dev. on 1 at 21,0, #2 at 21,1, and
#3 on 21,2.  Or /dev/sg[a-c].  

Here's a bit of code to do an inquiry once you think you have stuff
set up right.  Execute with a.out /dev/whatever.  It's a quick hack, no
real error checking...  

#include "/usr/src/linux/drivers/scsi/sg.h"  /* or wherever */
#include <stdio.h>
#include <fcntl.h>

#define REPLY_LEN 36

int main(int argc, char **argv)
{
int fd;
static unsigned char inquiry[]={0x12,0,0,0,REPLY_LEN,0};

struct sg_command
 {
  struct sg_header header;
  unsigned char bytes[4095-sizeof(struct sg_header)];
 } sg_command;

sg_command.header.pack_len = 6 + sizeof(struct sg_header);
sg_command.header.reply_len = REPLY_LEN + sizeof(struct sg_header);
sg_command.header.pack_id=0;
sg_command.header.result=0;
memcpy(sg_command.bytes, inquiry, 6);         

if((fd=open(argv[1], O_RDWR, NULL))==-1)
   {
    printf("Can't open %s.\n",argv[1]);
    exit(1);
   }

if (write(fd, &sg_command, sg_command.header.pack_len) < 
sg_command.header.pack_len)
   {
    puts("Didn't write all (any?) bytes.\n");
   }

if (read(fd, &sg_command, sg_command.header.reply_len)==-1)
   {
    puts("Read error.\n");
   }

printf("%s\n",&sg_command.bytes[8]);
}          

This, along with a look at struct sg_header in sg.h, should get you going.

-Craig

------------------------------

From: [email-masked] (M. K. Shenk)
Subject: Re: Making generic SCSI stuff work.
Date: 14 Oct 1994 12:02:50 GMT

In article <[email-masked]>,
M. K. Shenk <[email-masked]> wrote:
>A couple of folks wanted this.
...
>
>also be the order of detection on bootup... Note that ALL scsi devices
>will get an entry...tapes, disks, CD-ROMs, etc.  So someone with devices
>on scsi id#1, 2, and 5 would have the dev. on 1 at 21,0, #2 at 21,1, and
>#3 on 21,2.  Or /dev/sg[a-c].  

Oops.  I'm such a goof.  I meant #5 on 21,2.  Sorry.

-Craig.

------------------------------

From: [email-masked] (Dan Yergeau)
Crossposted-To: comp.os.386bsd.development,comp.sys.unix
Subject: Re: We a FAQ: Linux vs. *BSD!!!
Date: 14 Oct 1994 18:02:42 GMT

In article <[email-masked]>, [email-masked] (Jordan K. Hubbard) writes:
|> 
|> The only way we're going to stop this silliness is to simply start
|> ignoring the querants.  If someone asks "Which is better?" ...
|> and everybody just flat
|> out _ignores_ the question and goes about their business as if nothing
|> happened, folks will eventually get the point and stop asking.

IMNSHO, the question is usually asked by relative newbies.  These
people have not seen the question asked and ignored, so ignoring
the question will not make it go away.  And, there will always be
enough newbies around to get a thread going.

[flame wars argument deleted]

As there is no "reasonable" standard response, everyone tries to
interject their opinions, point out inaccuracies (often
inaccurately), etc.  Of course it degrades into a flame war.

|> No FAQ will ever satisfy the two sides, and would rapidly become
|> obsolete even if it did.

A Linux *vs.* BSD FAQ is probably not the best idea, but a short
and *neutral* information sheet comparing capabilities could work.
The biggest problem I see is how to handle the features of different
distributions of Linux/*BSD.

Of course, the issues of who has the superior filesystem, VM,
networking, etc. would have to be ignored, unless they are issues
that directly affect users.  Most *users* don't care about most of
these technical issues anyway.  It is only the geeky CS-types that
care and will get into flame wars about it.

Examples of issues that may directly affect users are: 
 - Archived Linux binaries always seem to require a specific
   version of a shared library.  Does this mean that I need several
   different versions to support different binaries?
 - How easy is it to increase swap?  Do I have to repartition my
   drive? 

|> One German magazine reviewer who compared FreeBSD
|> to Linux ended up making an unfavorable judgement of FreeBSD because
|> _it didn't have enough shells_ bundled in by default!  

Most magazine writers are idiots who would be more impressed if the
OS could run DOOM but crashed every 4 hours than if it were stable
and didn't trash their critical project the day before it was due.
Just look at Byte's Pournelle and the weenies that treat his column
and recommendations like the word of God.

|> This almost perfectly exemplifys the average querant - they don't
|> really want to know which is better in general (as if "better in
|> general" meant anything anyway), they want to know which is better for
|> THEM, and how the hell are we supposed to know that?

A neutral feature comparison would go a long way to answering that
question for THEM.  They would probably realize that they wouldn't
be disappointed with any choice.

And, if they did have specific concerns not answered directly by the
FAQ, the presence of a FAQ may help them to more carefully formulate
their questions.

--
Dan Yergeau                         You are in a twisty little passage
[email-masked]        of standards, all conflicting.
#include <std.disclaimer>

------------------------------

From: [email-masked] (Kai Petzke)
Subject: Re: Filesystem idea
Date: 14 Oct 94 12:07:45 GMT

[email-masked] (Albert Hui) writes:

>[email-masked]. (Tim Morley) writes:
>>Jeffrey Charles Schave <schave@PROBLEM_WITH_INEWS_GATEWAY_FILE> wrote:
>>>Riku Saikkonen ([email-masked]) wrote:
>>>> [automagically delete temporary file]

>>>,whatever(via cron). This script could check the amount of free space
>>>left on the drive, and if necessary, destroy any .o files.

>>You have to be a bit careful about this, I know of a system where
>>someone implemented this, and it was fine until a reboot was required,
>>with some strange and insignificant .o file the system refused to
>>boot....

>I heard of a story about a system (for non-programmers) deletes all
>core files every night.  Then a scientist wrote a paper and named the
>file "core"...

There is also the story of a poor guy named John Core, user name "core",
whose mail (from /var/spool/core) got deleted regularly.

I like the idea of a file attribute "temporary".  It could easily be
added to the ext2 filesystem, which already supports a set of other
file attributes.

Then you can easily add a daemon, which scans the filesystem and deletes
the oldest temporary stuff, after free space falls under a certain
pre-defined threshold.

Kai
-- 
Kai Petzke                      | How fast can computers get?
Technical University of Berlin  |
Berlin, Germany                 | Warp 9, of course, on Star Trek.
[email-masked]   |

------------------------------

From: [email-masked] (Andre Schoorl)
Subject: Re: 1.1.53 - fdformat - IOCTL error still there
Date: Wed, 12 Oct 94 22:34:44 GMT

In article <[email-masked]>,
Rene COUGNENC <[email-masked]> wrote:
>Ce brave Vincent Fatica ecrit:
>
>> Very shortly after patch52 came out, a few persons observed an IOCTL error
>> when using fdformat. I figured it would be better in 1.1.53, 

I have no problems with 1.1.53.  I can use fdformat, mformat, mount, etc...
just fine.  I'm running on a Dell 486 DX2 66.

I can't wait til 1.1.54 :^)

-- 
Andre Schoorl <[email-masked]>   PGP key available via finger/keyserver
C.Eng Student, U.Vic, Canada.  -> LINUX! <-  http://www-engr.uvic.ca/~aschoorl

------------------------------

From: [email-masked] (David Cure)
Subject: Re: Mathematical functions with c
Reply-To: [email-masked]
Date: Wed, 12 Oct 94 11:26:06 GMT

In article [email-masked], [email-masked] (Norbert Kuemin) writes:
>Does anyone now which library i must link to use the definitions from
>/usr/include/math.h ???
>

        use -lm (libm.a) in command line of compil.

                David.

---

   _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
   David Cure - Ifremer/Brest - SISMER - BP70 - 29280 PLOUZANE - FRANCE
     Email : [email-masked] / Tel : 98.22.46.42 - 98.22.42.10

   " Apres avoir vu la lumiere, on ne retourne pas dans les tenebres "

------------------------------

From: Kevin Martinez <[email-masked]>
Subject: Re: Optimizing the NFS server
Date: Sun, 16 Oct 1994 05:29:35 GMT

[email-masked] (Thomas Koenig) writes:

>What about he NFS server?  It's also far from fast, at the moment;
>I see several bottlenecks:

>- Other Unices have the advantage of being able to server multiple
>  requests by having multiple in-kernel NFS servers, which can serve
>  multiple requests concurrently.  For example, this means that one
>  process can do the CPU work to check a request while another one
>  is waiting for data to come from the disk.  Linux nfsd, which is
>  a user-level daemon, can't do this (being single - threaded).

NFS client performance has come a long way! I'd love to see similar 
effort on the server side. How much would multiple nfsd processes help if 
the server ran as a kernel level process? I've tried multiple user level 
nfsd processes but only one ever gets used. Linux doesn't seem to need 
the SunOS style biod daemons.... 

I am using a Linux machine as a NFS server for industrial processes. I  
see great potential in this - especially if I could run a few more NFS  
clients per server.

Any interest in a nfswatch port?

-- 
========================================================================
 Kevin Martinez           Fear the Government  that fears your Scanner!
 [email-masked]            I owe all my success to Roly Poly Fish Heads!
========================================================================

------------------------------

From: [email-masked] (Martin Spott)
Subject: Re: Writing to OS/2 HPFS...how soon?
Date: 12 Oct 1994 17:03:28 GMT

: Does anyone know when support for writing to an OS/2 HPFS will be
: available?
As far as I know it will take too long time to fait for it.

Martin.
--

EMail:                 bevorzugt privat: [email-masked]
             notfalls auch "dienstlich": [email-masked]

------------------------------

From: [email-masked] (Jeff Kesselman)
Subject: Re: A badly missed feature in gcc
Date: Sat, 15 Oct 1994 01:52:18 GMT

In article <[email-masked]>,
H. Peter Anvin <[email-masked]> wrote:
>One thing: would people stop sending me compiler samples?  I *know*
>that it is not in the current version of the C standard, and I know
>there are people out there who think ANSI C, the 1990 version, is the
>Word of God[TM], but all I did was mention that:
>
>a) A number of C compilers support it as an extension,
>b) It has been proposed for inclusion in a future version of the ANSI
>   C standard,
>c) There have yet surfaced a *non-artificial* example of code that it
>   would break (which would, if such code existed, make (b) a Bad
>   Thing[TM]).
>
>Please let's put this thread to rest.
>
>       /hpa
>-- 
>INTERNET: [email-masked]             --- Allah'u'abha ---
>IBM MAIL: I0050052 at IBMMAIL     HAM RADIO:   N9ITP or SM4TKN
>FIDONET:  1:115/511 or 1:115/512  STORMNET:    181:294/1 or 181:294/101
>Laughter is the best medicine -- Quayle in '94.

I think, perhapse, you are missing the point of the examples because of 
possibly not having studied compiler theory (no shame in that, we all 
have to make choices as to what to study.)  There really is no such 
thing as an 'artificial example'.  A language syntax is defined by the 
set of legal programs that can be written with it.  There are no 'better 
or worse' programs as far as the synatx is concerned, all that is legal 
has equal standing.  This is pretty basic to language theory.  Thsu the 
examples are legal syntax, that woudl become illegal, and thats all that 
really matters.

Jeff Kesselman

------------------------------

Date: 16 Oct 1994 16:44:18 -0000
From: [email-masked] (Robert A. Piacente)
Reply-To: [email-masked]
Subject: Re(2): Linux For Mac

Is there a port being worked ? I've asked this before. At the Unix Expo I was
told that no Mac
or Mac/PPC would be worked. On the other hand they would be an IBM PPC port
..... someone had donated the equipment and teck.

------------------------------

From: [email-masked] (Matthew Dillon)
Subject: Re: Improving SLIP latency under Linux
Date: 16 Oct 1994 01:33:43 -0700

:In article <[email-masked]> [email-masked] (Michael Callahan) writes:
:>In article <[email-masked]>,
:>John Richardson <[email-masked]> wrote:
:>>In article <[email-masked]>,
:>>Matthias Urlichs <[email-masked]> wrote:
:>>>The reasonable thing to do here is to increase the baud rate you use when
:..
:Actually, what you would really like is to have a SLOW baud rate
:for transmitting to the modem, and a FAST baud rate for receiving
:from it.  The problem with having a FAST baud rate for transmitting
:to the modem is that the Linux host can fill up the modem's 
:transmit buffer rapidly, at which point the modem has a couple
:seconds of data to send, so _no matter what the Linux host does_,
:a new interactive packet will have to wait a couple of seconds
:for delivery.
:
:I wouldn't be surprised if a 9600 baud connection to a 14.4
:modem session gave the best latency results for interactive
:traffic with simultaneous bulk traffic.  On the other hand,
:it's slow.
:
:Michael
:---
:Michael Callahan
:[email-masked]

    Actually, Mike, latency goes through the roof.  The problem is that
    an error correcting modem will packetize your data for transmission
    and, of course, receives data from the other modem in packets.  It
    must then transfer the 'packet' to the computer via the host serial
    port.

    You basically want as FAST a connection as possible to reduce this
    latency.  The difference between 38400 and 57600 (or 76800) is VERY 
    noticable even if the modem itself is only a 14.4, *especially*
    for small interactive packets.

                                                -Matt

-- 

    Matthew Dillon              [email-masked]
    1005 Apollo Way             ham: KC6LVW (no mail drop)
    Incline Village, NV. 89451  Obvious Implementations Corporation
    USA                         Sandel-Avery Engineering
    [always include a portion of the original email in any response!]

------------------------------

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