/dev/osm (was: Re: Logging console messages to a printer.)

Bob Rinne bobr at idca.tds.PHILIPS.nl
Mon Jan 8 19:51:52 AEST 1990

In article <1665 at ctisbv.cti-software.nl> pim at cti-software.nl (Pim Zandbergen) writes:
>mark at zok.UUCP (Mark W. Snitily) writes:
>>   Device "osm" stands for "operating system messages".

>I have rebuilt the kernel (ISC 2.0.1) with osm installed
>but no /dev/osm is created.

>Can anybody help me with major and minor numbers ?

To get the major number you can look into field six of the mdevice entry
for osm.  Field six is the major number for character devices and field
five is the major number for block devices.  Field three will have a 'b'
for block and a 'c' for character...  more information is in mdevice(4)
in the "UNIX System V/386 Release 3.2 Programmer's Reference Manual".

The OSM minor numbers are:
	0 - read device that never returns EOF... therefore anything
	    that reads it will always be reading till a signal occurs.
	1 - reads current contents of buffer and returns EOF.
	2 - read device that never returns EOF, but starts from the
	    beginning of the circular buffer instead of the logical
	    "current" position.

I remember seeing documentation on these somewhere in the 3.0/3.1
releases from AT&T, but it is nowhere to be found in the 3.2 release

If you don't want to do the mknod by hand everytime you reboot put
the following in the file /etc/conf/node.d/osm...

osm	osm.0	c	0
osm	osm.1	c	1
osm	osm.2	c	2

Reference idmknod(1M) in the "System/User Reference Manual".  I don't
know the prescribed names for the devices from AT&T since I can't find
any reference to them, so the names in column two are my own.

>On our AT&T 3B2 running SYS V R 3.2.1 there's a utility
>called 'errint' for reading /dev/osm. 
>Is this supposed to be standard in SYS V R 3.2?

Nope, nothing in any of the V.3.x release from AT&T so I doubt if it
would be in any 386/ix release.  "cat" will work although it works on
BUFSIZ boundaries ... This means up to BUFSIZ bytes will not be in
the log file.

#  Bob Rinne                              Internet rinne at idca.tds.philips.nl #
#  Philips TDS, Dept SSP                  UUCP       ...!mcvax!philapd!rinne #

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