[pups] Swap device in V6?

[Jay Jaeger]

In case someone didn't put 2+2 together...  The V6 distribution has various 
unix kernels.  I don't recall for sure which kernel is linked to /unix, but 
for sure it is only one of them.

So, if /rpunix is linked to /unix, and you boot rkunix, and then do a ps, 
it will search /unix for the symbol for swapdev, look for the RP device in 
/dev, and not find one.  no swap dev.

The cure is, of course, quite simple:

# chdir /
# ln rkunix unix

And ps will now work fine.

[ Ian might have gotten this directly had he not hidden his real e-mail 
address...  ;-) ]

Jay Jaeger


At 09:32 AM 2/27/01 +1100, you wrote:

>Date: Sun, 25 Feb 2001 23:49:22 -0800
>From: "Ian King" <iking at killthewabbit.org>
>Subject: [pups] Swap device in V6?
>
>This is a multi-part message in MIME format.
>
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>Content-Type: text/plain;
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>I'm working with the install image provided by Ken Wellsch, and when I =
>execute the 'ps' command I get an error that says "no swap device".  I'm =
>
>------------------------------
>
>Date: Mon, 26 Feb 2001 10:27:12 -0800
>From: Ian King <iking at microsoft.com>
>Subject: RE: [pups] Swap device in V6?
>
>I, too, have /dev/rk0 mknod'ed as 0,0.  Relaetd to this, ps does something
>odd (at least to my experience) with the open() system call - it calls 'open
>("/dev")', without a second argument for mode; that seems like a no-no in C,
>
>- -----Original Message-----
>From: Ken Wellsch [mailto:kwellsch at tampabay.rr.com]
>Sent: Monday, February 26, 2001 9:52 AM
>To: Roger Ivie
>Cc: PUPS at minnie.cs.adfa.edu.au
>Subject: Re: [pups] Swap device in V6?
>
>The "ps" command source appears to be poking around /dev looking for a
>block device that matches the kernel value for swapdev (or something like
>that) and confirming it is a block device.
>
>Yet I see I have /dev/rk0 mknod'ed 0/0 and it is a block device but "ps"
>still gripes about "no swap device."
>
>So I'm missing something I guess.
>
>Date: Tue, 27 Feb 2001 08:44:23 +1100 (EST)
>From: John Holden <johnh at psych.usyd.edu.au>
>Subject: Re: [pups] Swap device in V6?
>
<< snip >>


>The 'ps' command looks up the symbol table of the unix kernel, and gets
>the device entry for swap (_swapdev), and the process table (_proc)
>It would open /dev as file, and read the directory entries to find a matching
>device entry, so it then had the name of a device to open (you cannot open
>a device based only in the major and minor device entries from a user 
>process).
>It also uses /dev to decode tty entries into names.
>
>For 'ps' to work correctly, /unix had to be linked to the real kernel, say
>rkunix.

---	
Jay R. Jaeger					The Computer Collection
cube1 at home.com			visit http://members.home.net/thecomputercollection


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