Subject: RE: NFS Swap File !!!!

From: Iain Grant <[email-masked]>
Date: Tue, 20 Apr 1999 14:54:58 +0100

Russell,

Thanks for the advice. We've stopped going down that route. And are now
ignoring swap files/devices altogether.

So, At the moment we have got to the following level.

1. Successfully cross-compiled a linux 2.1.132 kernel for our EBSA
2. Copied the netwinder kit
(ftp.netwinder.org/pub/ccc/images/dm-2.1-12.tar.gz ) onto a local drive of a
RedHat 5.2 Intel box
3. NFS booted the EBSA to the extracted netwinder kit on that Intel box

The system can boot up to runlevel 3 ( removing some of the invalid startup
files )

The problem we are hitting at the moment is, we can telnet from the EBSA to
other systems on the net. However we cannot telnet to the EBSA from those
systems. After looking at the startups I have found that some programs (
including tftpd ) print "Illegal Instruction" and sometimes ( core dump)
when executed.

We did pull the RPM files from the arm-linux ftp site to try and replace the
bad files, but found that there is not an rpm program there to install them
with. ( You guessed it, the one from the netwinder image gives an illegal
instruction error ).

Another piece of information is that we pulled the files from the instimage
area of armlinux.org and replaced files in the /bin area of the netwinder
kit with them, this fixed a couple of programs ( bash and ls were two)
although replacing the ps program still put up the 'Illegal Instruction
message'.

Have you, or anyone else got any more words of wisdom that could help us get
further.

Thanks again

Iain

> ----------
> From: 	Russell King[SMTP:[email-masked]]
> Sent: 	20 April 1999 9:09 
> To: 	Iain Grant
> Cc: 	[email-masked]
> Subject: 	Re: NFS Swap File !!!!
> 
> Iain Grant said:
> > When we boot the EBSA we always get a 'bad swap file' error message. ( I
> > have even tried adding the dd and mkswap instructions to the rc.sysinit
> of
> > the EBSA but that didn't work either )
> 
> With Linux, it is not possible to have a swap file over NFS.
> 
> > If we cannot get this to work I was thinking about using a ramdisk as
> the
> > swapdisk. Don't know if this will work or not but I'm willing to give it
> a
> > try.
> 
> This will not gain you any advantage.  It's better to leave the memory
> free
> for Linux to work out what the best use of the memory is than to allocate
> it
> to a swap device.
> 
> Since Linux does not require a swap file, I would suggest not using one if
> you do not need one.
> 
> --
> Russell King ([email-masked])
> Millbank Electronics Tel: 01825 764811 Fax: 01825 761620
> 
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---

From: Scott Bambrough <[email-masked]>
Date: Tue, 20 Apr 1999 14:18:11 -0400

> including tftpd ) print "Illegal Instruction" and sometimes ( core dump)

tftp, tftpd are probably broken.  There were bugs in glibc that prevented things
from running.
As well there are bugs in the implementation of socket calls and mmap in glibc
from that disk image.  I suggest you look at the tools section on netwinder.org
for more information.

One other thing to note, is the netwinder image was compiled specifically for
arm arch 4.  It will use instructions specific to that architechure, that aren't
supported on earlier architechures or Risc PC's.

> although replacing the ps program still put up the 'Illegal Instruction

The netwinder disk image is mostly an ELF system, while Russell's RPMS are
a.out.  The disk image may not have all the proper libraries required for
Russell's binaries.  I'm not sure how ELF and a.out dynamically linked
executables will coexist.  I can forsee difficulties there.

> Have you, or anyone else got any more words of wisdom that could help us get

Nope.  Do you have any more info on the invalid instructions.  They aren't
floating point instructions are they?  If so you may need the FPE loaded, or use
a kernel with the NWFPE built in.

Scott

---

From: Russell King - ARM Linux Admin <[email-masked]>
Date: Tue, 20 Apr 1999 19:54:24 +0100 (BST)

> supported on earlier architechures or Risc PC's.

Scott,

The Netwinder is based on the EBSA285, which in turn was based (to a small extent)
on the EBSA110.  All of these architectures will work with ARM Arch 4 binaries.

> a kernel with the NWFPE built in.

The kernel will allow binaries to run to a limited extent without any FP support
loaded/compiled in.  However, it is generally a good idea to fetch the new 2.2
Acorn FPE (in my testing/ directory on the FTP site), or compile NWFPE in.
   _____
  |_____| ------------------------------------------------- ---+---+-
  |   |        Russell King       [email-masked]      --- ---
  | | | |  http://www.arm.linux.org.uk/~rmk/armlinux.html    /  /  |
  | +-+-+                                                     --- -+-
  /   |               THE developer of ARM Linux              |+| /|\
 /  | | |                                                     ---  |
    +-+-+ -------------------------------------------------  /\\\  |
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---

From: Philip Blundell <[email-masked]>
Date: Tue, 20 Apr 1999 20:33:02 +0100

>I'm not sure how ELF and a.out dynamically linked

Actually, it should be fine.  There are no namespace clashes between them, 
except possibly for the ELF binaries that accidentally got linked against 
/usr/lib/ld.so.1 (and even they should be OK, since the a.out dynamic linker 
is traditionally in /lib).

p.