[2889] in Release_Engineering
Request for reconfiguration of the ULTRIX kernel
daemon@ATHENA.MIT.EDU (nschmidt@Athena.MIT.EDU)
Tue Jul 7 08:35:30 1992
From: nschmidt@Athena.MIT.EDU
To: mar@Athena.MIT.EDU
Cc: rel-eng@Athena.MIT.EDU, nschmidt@Athena.MIT.EDU
Date: Tue, 07 Jul 92 08:35:18 EDT
Could I have your opinion on the following request, which comes from Joe
Ferreira? My question consists of three parts - (1) is it doable given the
other requirements of the Athena environment, (2) if so, is it a good idea,
and (3) if 1 and 2 are 'yes' is it something that would have to wait until
the next release to do on a large scale?
Naomi
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To: nschmidt@Athena.MIT.EDU
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Subject: Re: Forthcoming problems with Arc/Info
Date: Mon, 06 Jul 92 18:48:42 EDT
Naomi,
[... other stuff went here ...]
On this latter point, attached is another memo from Tom G. regarding the
availability of larger swap spaces and shared memory in the standard Athena
release configurations for DECstations. As you see from the note, the
capabilities of the standard Athena machine affects our ability to 'wait
until January'. That is, we'd be better able to handle class needs if color
athena workstations in public clusters (such as the DECstations) had the
capabilities that Tom outlines.
-- Joe F.
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ktazar@Athena.MIT.EDU, jdevans@Athena.MIT.EDU,
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Subject: Permanent kernel solutions
Date: Mon, 06 Jul 92 18:00:12 EDT
From: Thomas H. Grayson <tgrayson@Athena.MIT.EDU>
Joe,
The Ultrix kernel shipped with the Athena 7.4 release continues to
lack the enhancements we routinely require to operate advanced
software such as Arc/Info, Oracle, and Ingres on DECstations.
These packages require extra swap space, additional semaphores, and
adequate shared memory. To the best of my knowledge, the Ultrix
kernel can be configured to accommodate these features *without*
incurring any additional cost in terms of software compatibility,
memory usage, or disk usage. Ezra Peisach, who has prepared special
kernels for us, can confirm this. Our own experience with the special
kernel on pelli has uncovered no anomalous behavior. In the past,
we have pursued the faculty liaison to get custom kernels as needed for
the workstation `pelli'. We can continue to do so indefinitely, but
this strategy is undesirable for the following reasons:
1) We need to get a new kernel configured for `pelli' with
every Athena release, an administrative process we must go
through twice annually.
2) While we can set up `pelli' easily enough, we would like
to take advantage of Arc/Info's connections to remote RDBMSs
such as Oracle or Ingres from workstations other than `pelli'.
While our license for Arc/Info allows us up to 16 simultaneous
users from any DECstation on the network, we cannot take
advantage of the RDBMS links from any other workstation because
of the special shared memory requirements of this component of
Arc/Info. Our lab and our students would be well served by
increasing the availability of this functionality.
3) Enhancing the Ultrix kernel parameters will enable the
Athena community at large, not just our cluster, to install and
use their own advanced software tools. Now that Athena is no
longer
a research experiment but a production computing environment,
the demand for such capabilities will grow. Athena itself can
help encourage this growth by installing the Ultrix SQL subsets
in a locker by default, so that we do not have to obtain the
tape
and use valuable local disk space for this purpose.
I advocate that the standard Athena Ultrix kernel for DECstations be
reconfigured with the parameters that follow in the appendix. I
hope you will concur with me and contact the faculty liaison's office
to
convince them that these enhancements benefit not just us but the
entire Athena community.
- - -- Tom Grayson
Appendix: Suggested Ultrix parameters
In /sys/conf/mips/MACHINENAME (the kernel configuration file):
# Shared memory
smmax 1024
smseg 16
#
# Use the defaults for the following two parameters (which are as
# specified below).
# smsmat 0
# maxdsize 32
#
# Extra swap device
# For workstations with local disks, enabling swapping on a second
# disk will both improve performance and increase the size and
# number of applications that the computer can run.
swap on rz3b and rz1b
In /usr/include/sys/sem.h (the semaphore configuration file):
/* Semaphore parameters */
SEMMNI 15 /* # of semaphore sets */
SEMMSL 25 /* # of semaphores per set */
SEMMNS 120 /* # of semaphores system-wide */
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