4BSD/usr/doc/vmunix/setup.t

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.bd S B 3
.TL
Setting up the Fourth Berkeley Software Tape*
.br
Draft of: November 15, 1980
.AU
William N. Joy
Ozalp Babaoglu
Keith Sklower
.AI
Computer Science Division
Department of Electrical Engineering and Computer Science
University of California, Berkeley
Berkeley, California 94720
.PP
.de IR
\fI\\$1\fP\\$2
..
.de UX
\s-2UNIX\s0\\$1
..
.FS
*Portions of this document are adapted from
``Setting Up Unix/32V Version 1.0''
by Thomas B. London and John F. Reiser.
.FE
The basic distribution tape can be used only on a DEC VAX-11/780**
with RM03, RM05 or RP06 disks and with
TE16, TU45 or TU77 tape drives.
We have the ability to make tapes for systems with UNIBUS** disks, but
.FS
** DEC, VAX, UNIBUS and MASSBUS are trademarks of
Digital Equipment Corporation.
.FE
.FS
\(dg \s-2UNIX\s0 is a Trademark of Bell Laboratories.
.FE
such tapes are inherently rather system-specific, and will not be
discussed here.
The tape consists of some preliminary bootstrapping programs followed by
one dump of a filesystem (see
.IR dump (8)\(dg\(dg)
.FS
\(dg\(dgReferences of the form X(Y) mean the subsection named
X in section Y of the
.UX
programmer's manual.
.FE
and one tape archive image (see
.IR tar (1));
if needed,
individual files can be extracted
after the initial construction of the filesystems.
.PP
If you are set up to do it,
it is a good idea immediately to make a copy of the
tape to guard against disaster.
The tape is 9-track 1600 BPI and contains some 512-byte records
followed by many 10240-byte records.
There are interspersed tapemarks; end-of-tape is signalled
by a double end-of-file.
.PP
The tape contains binary images
of the system and all the user level programs, along with source
and manual sections for them.
There are about 5600
.UX \(dg
files altogether.
The first tape file contains bootstrapping programs.
The second tape file is to be put on one filesystem
called the `root filesystem', and contains essential binaries and enough
other files to allow the system to run.
The third tape file has all of the source and documentation.
Altogether the files provided on the tape occupy approximately 52000 512 byte
blocks.\(dd
.FS
\(dd\s-2UNIX\s0 traditionally talks in terms of 512 character blocks, and
for consistency
across different versions of
.UX
and to avoid mass confusion, user programs in the Virtual Vax version of the
system also talk in terms of 512 blocks, despite the fact that the file
system allocates 1024 byte blocks of disk space.
All user progras such as
.IR ls (1)
and
.IR du (1)
speak in terms of 512 byte blocks; only system maintenance programs such
as
.IR mkfs (8),
.IR fsck (8)
.IR dump (8),
and
.IR df (1),
speak to 1024 byte blocks.
It is true that i/o is most efficient in 1024
byte quantities, but it is most natural for the user to think of this
as ``2 blocks at a time.''
In any case, packs remain sectored 512 bytes per sector, and at the lowest
driver levels the system deals with 512 byte disk records.
.FE
.SH
Making a disk from tape
.PP
Before you begin to work on the remainder of this document, be sure you
have an up to date manual, and that you have applied all updates
to the manual which were provided with it, in the correct order.
.PP
Perform the following bootstrap procedure to obtain
a disk with a root filesystem on it.
.IP 1.
Mount the magtape on drive 0 at load point, making
sure that the ring is not inserted.
.IP 2.
Mount a disk pack on drive 0.
It is preferable that the pack be formatted (e.g. using the standard
DEC standalone utility); we provide programs for formatting RM03's
and RP06's below, but RM05's must be pre-formatted by the DEC utility.
.IP 3.
Key in at location 50000 and execute the following boot program:
You may enter in lower-case, the LSI-11 will echo in upper-case.
The machine's printouts are shown in boldface,
explanatory comments are within ( ).
Terminate each line you type by carriage return or line-feed.
.RT
.DS
\fB>>>\|\fRHALT
\fB>>>\|\fRUNJAM
\fB>>>\|\fRINIT
\fB>>>\|\fRD 50000 20009FDE
\fB>>>\|\fRD+ D0512001
\fB>>>\|\fRD+ 3204A101
\fB>>>\|\fRD+ C114C08F
\fB>>>\|\fRD+ A1D40424
\fB>>>\|\fRD+ 008FD00C
\fB>>>\|\fRD+ C1800000
\fB>>>\|\fRD+ 8F320800
\fB>>>\|\fRD+ 10A1FE00
\fB>>>\|\fRD+ 00C139D0
\fB>>>\|\fRD+ 00000004
\fB>>>\|\fRE 50000/NE:A
\&... (machine prints out values, check typing)
\fB>>>\|\fRSTART 50000
.DE
.IP
The tape should move and the CPU should halt at location 5002A.
If it doesn't, you probably have entered the program
incorrectly.
Start over and check your typing.
.IP 4.
Start the CPU with
.DS
\fB>>>\|\fRSTART 0
.DE
.IP 5.
The console should type
.DS
.I
\fB=\fR
.R
.DE
If you have an RM-05 you must already have a formatted pack,
and should skip to step 7.
If the disk pack is otherwise already formatted, skip to step 6.
Otherwise, format the pack with:
.DS
(bring in standalone RP06 formatter)
\fB=\|\fRrp6fmt
\fBformat : Format RP06/RM03 Disk\fR

\fBMBA no. : \fR0 (format spindle on mba \# 0)
\fBunit : \fR0 (format unit zero)
(this procedure should take about 20 minutes for an RP06, 10 for an RM03)
(some diagnostic messages may appear here)

\fBunit : \fR\-1 (exit from formatter)
\fB=\fR (back at tape boot level)
.DE
.IP 6.
Next, verify the readability of the pack via
.DS
(bring in RP06 verifier)
\fB=\|\fRrpread
\fBdread : Read RP06/RM03 Disk\fR

\fBdisk unit : \fR0 (specify unit zero)
\fBstart block : \fR0 (start at block zero)
\fBno. blocks :\fR (default is entire pack)

(this procedure should take about 10 minutes for a RP06)
(some diagnostic messages may appear here)
\fB# Data Check errors : nn\fR (number of soft errors)
\fB# Other errors : xx\fR (number of hard errors)
\fBdisk unit: \fR\-1 (exit from rpread)
\fB=\fR (back to tape boot)
.DE
If the number of `Other errors' is not zero, consideration
should be given to obtaining a clean pack before proceeding
further.
.IP 7.
Create the root file system with the following procedure:
.DS
(bring in a standalone version of the \fImkfs\fR (8) program)
\fB=\|\fRmkfs
\fBfile sys size:\fR 7942 (number of 1024 byte blocks in root)
\fBfile system:\fR hp(0,0) (root is on drive zero; first filsys there)
\fBisize = 5072\fR (number of inodes in root filesystem)
\fBm/n = 3 500\fR (interleave parameters)
\fB=\fR (back at tape boot level)
.DE
You now have a empty UNIX root filesystem.
To restore the data which you need to boot the system, type
.DS
(bring in a standalone \fIrestor\fR\|(8) program)
\fB=\|\fRrestor
\fBTape?\fR ht(0,1) (unit 0, second tape file)
\fBDisk?\fR hp(0,0) (into root file system)
\fBLast chance before scribbling on disk.\fR (just hit return)
(30 second pause then tape should move)
(tape moves for a few minutes)
\fBEnd of tape\fR
\fB=\fR (back at tape boot level)
.DE
Now, you are ready to boot up
.UX.
.SH
Booting UNIX
.PP
Now boot UNIX:
.DS
(load bootstrap program)
\fB=\fR\|boot
\fBBoot\fR
\fB: \fRhp(0,0)vmunix (bring in \fIvmunix\fR off root system)
.DE
The bootstrap should then print out the sizes of the different
parts of the system (text, initialized and uninitialized data) and then
the system should start with a message which looks (like):
.DS
.B
87844+15464+130300 start 0x530
VM/UNIX (Berkeley Version 4.1) 11/10/80
real mem = \fIxxx\fB
avail mem = \fIyyy\fB
WARNING: preposterous time in file system \-\- CHECK AND RESET THE DATE!
ERASE IS CONTROL-H!!!
\fB#\fR
.R
.DE
The
.I
mem
.R
messages give the
amount of real (physical) memory and the
memory available to user programs
in bytes.
For example, if your machine has only 512K bytes of memory, then
xxx will be 524228, i.e. exactly 512K.
The ``ERASE-IS'' message is part of /.profile
which was executed by the root shell when it started. You will
probably want to change /.profile somewhat.
.PP
UNIX is now running,
and the `UNIX Programmer's manual' applies.
The `#' is the prompt from the Shell,
and indicates you are the super-user.
You should first check the integrity of the root file system by
giving the command
.DS
\fB#\fR fsck /dev/rrp0a
.DE
The output from
.I fsck
should look something like:
.DS
.B
/dev/rrp0a
File System: Volume:

** Checking /dev/rrp0a
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Free List
282 files 1766 blocks 5677 free
.R
.DE
.PP
If there are inconsistencies in the file system, you may be prompted
as to whether to apply corrective action; see the document describing
.I fsck
for information.
.SH
Extracting /usr.
.PP
The next thing to do is to extract the rest of the data from
the tape.
Comments are enclosed in ( ); don't type these.
The number in the first command is the
size of the filesystem to be created, in 1024 character blocks,
just as given to the standalone version of
.I mkfs
above.
(If you have an RM-03 rather than an RM-05 or RP-06 use ``41040'' rather than
``145673'' in the procedure below.)
.DS
\fB#\|\fRdate \fIyymmddhhmm\fR (set date, see \fIdate\fR\|(1))
\fB#\|\fRpasswd root (set password for super-user)
\fBNew password:\fR (password will not echo)
\fBRetype new password:\fR
\fB#\|\fR/etc/mkfs /dev/rrp0g 145673 (create empty user filesystem)
\fBisize = 65488\fR (this is the number of available inodes)
\fBm/n = 3 500\fR (freelist interleave parameters)
(this takes a few minutes)
\fB#\|\fR/etc/mount /dev/rp0g /usr (mount the usr filesystem)
\fB#\|\fRcd /usr (make /usr the current directory)
\fB#\|\fRcp /dev/rmt12 /dev/null (skip first tape file (tp format))
\fB#\|\fRcp /dev/rmt12 /dev/null (skip second tape file (root))
\fB#\|\fRtar xpb 20 (extract the usr filesystem)
(this takes about 20 minutes)
\fB#\|\fRrmdir lost+found
\fB#\|\fR/etc/mklost+found (a directory for \fIfsck\fR)
\fB#\|\fRdd if=/usr/mdec/uboot of=/dev/rrp0a bs=1b count=1
(write boot block so \fIreboot\fR(8) disk boot scheme will work)
\fB#\|\fRcd / (back to root)
\fB#\|\fRchmod 755 / /usr
\fB#\|\fR/etc/umount /dev/rp0g (unmount /usr)
.DE
All of the data on the tape has now been extracted.
The tape will rewind automatically.
.PP
You should now check the consistency of the /usr file system by doing
.DS
\fB#\fR fsck /dev/rrp0g
.DE
In order to use the /usr file system, you should now remount it by
saying
.DS
\fB#\fR /etc/mount /dev/rp0g /usr
.DE
.SH
Making a UNIX boot floppy
.PP
The next thing to do is to make a new
.UX
boot floppy, by adding some files to a copy of your current console floppy,
using
.I flcopy
and
.IR arff (8).
.PP
Place your current floppy in the console, and issue the following commands:
.DS
\fB#\fR cd /usr/src/sys/floppy
\fB#\fR mkdir fromdec (scratch sub-directory)
\fB#\fR cd fromdec
\fB#\fR arff xv (extract all files from floppy)
(list of files prints out)
\fB#\fR flcopy \-t3
(system reads header information off current floppy)
\fBChange Floppy, Hit return when done.\fR
(waits for you to put clean floppy in console)
(copies header information back out after you hit return)
\fB#\fR rm floppy (don't need copy of old header information)
\fB#\fR rm dm* db* vmb.exe (don't need these files with \s-2UNIX\s0)
\fB#\fR arff cr * (add basic files)
\fBAre you sure you want to clobber the floppy?\fR
yes (clobbering is, essentially, a \fBmkfs\fR)
\fB#\fR cd ..
\fB#\fR rm \-r fromdec (remove scratch directory)
\fB#\fR arff r * (add UNIX boot files to floppy)
.DE
More copies of this floppy can be made using
.B flcopy.
.PP
You should now be able to reboot using the procedures in
.IR reboot (8).
First you should turn on the auto-reboot switch on the machine.
Then try a reboot, saying
.DS
\fB#\fR /etc/reboot \-s
.DE
which you can read about in
.IR reboot (8).
.SH
Taking the system up and down
.PP
Normally the system reboots itself and no intervention is needed at
the console command level (e.g. to the LSI-11 ``>>>'' prompt.)\(dg
.FS
\(dgIf you are going to make your root device be something other
than a MASSBUS disk, you will have to change the file RESTAR.CMD on the floppy,
to pass the block device index of the major device to be booted from
to the system in a register after, e.g., a power-fail.
.FE
In fact, after such a reboot, the system normally performs a reboot
checking the disks, and then goes back to multi-user mode. Such a reboot
can be stopped (after it prints the date) with a delete (interrupt).
.PP
If booting from the console command level is needed, then the command
.DS
\fB>>>\fR B RPS
.DE
will boot from unit 0 on mba 0 (RM-03, RM-05 or RP-06), bringing in
the file ``hp(0,0)vmunix''. Other possibilities are ``B RPM''
which boots and runs the automatic reboot procedure or ``B ANY''
which boots and asks for the name of the file to be booted.
Note that ``B'' with no arguments is used internally by the reboot
code, and shouldn't be used.
.PP
To bring the system up to a multi-user configuration from the single-user
status after, e.g., a ``B RPS''
all you have to do is hit control-d on the console. The system
will then perform /etc/rc,
a multi-user restart script, and come up on the terminals which are
indicated in /etc/ttys.
See
.IR init (8)
and
.IR ttys (5).
Note, however, that this does not cause a file system check to be performed.
Unless the system was taken down cleanly, you should run
``fsck \-p'' or force a reboot with
.IR reboot (8)
to have the disks checked.
.PP
To take the system down to a single user state you can use
.DS
\fB#\fR kill 1
.DE
when you are up multi-user.
This will kill all processes and give you a shell on the console,
as if you had just booted.
.PP
If you wish to change the terminal lines which are active you can edit the file
/etc/ttys, changing the first characters of lines, and then do
.DS
\fB#\fR kill \-1 1
.DE
See
.IR init (8)
and
.IR getty (8)
for more information.
.SH
Backing up the system
.PP
Before you change the source for the kernel it is wise to make
a backup. The following will do this:
.br
.ne 5
.ID
.nf
\fB#\fR cd /usr/src
\fB#\fR mkdir distsys distsys/h distsys/sys distsys/dev distsys/conf distsys/stand
\fB#\fR cd sys/sys
\fB#\fR cp * /usr/src/distsys/sys
\fB#\fR cd ../h
\fB#\fR cp * /usr/src/distsys/h
\fB#\fR cd ../dev
\fB#\fR cp * /usr/src/distsys/dev
\fB#\fR cd ../conf
\fB#\fR cp * /usr/src/distsys/conf
\fB#\fR cd ../stand
\fB#\fR cp * /usr/src/distsys/stand
.fi
.DE
This allows you to find out what you have done to the distribution
system by later running the command
.IR diff (1),
comparing these directories.
.SH
Organization
.PP
The system source is kept in the subdirectories of /usr/src/sys.
The directory
.B sys
contains the mainline kernel code, implementing system calls, the
file system, virtual memory, etc.
The directory
.B dev
contains device drivers and other low-level routines.
The directory
\fBconf\fR
contains CPU-dependent information on physical and logical
device configuration.
The directory
.B h
contains all the header files, defining structures and system constants.
\fBN.B.: The system header files in /usr/src/sys/h are copies
of the files in /usr/include/sys. Since programs which depend on constants
in /usr/include/sys/param.h must correspond to the running system, you
should be careful to make new header files available whenever you
resize the system or otherwise change the header files.\fR
.PP
You should expect to have to make some changes to the
.B conf
directory
and perhaps to some of the header files in the
.B h
directory to resize some things.
.PP
The
conf,
sys
and
dev
directories each have their own
.I makefile
controlling recompilation.
The
.B sys
makefile is the master makefile; new versions of the kernel are
created as ``vmunix'' in the
.B sys
directory.
If changes are made in other directories, then the following commands:
.DS
\fB#\fR cd ../sys
\fB#\fR rm vmunix
\fB#\fR make
.DE
will cause all needed recompilations to be done. It is often convenient
when making changes in
.B dev
or
.B conf
to just run
.I make
there first.
.PP
Finally note that the directory
.B stand
which is not part of the system proper.
If you add new peripherals such as tapes or disks you will want
to extend the standalone system to be able to deal with these.
It too, has a
.I makefile
which you can look at.
.SH
Isolating local changes conditionally
.PP
You will notice that the system, as distributed, has conditional code
in it. The current Berkeley system, on ``Ernie Co-vax'' is made
by defining IDENT in the \fBmakefile\fRs to be
.DS
IDENT= \-DERNIE \-DUCB
.DE
This enables the conditional code both for Berkeley and for this
particular machine.
It is traditional to pick a monicker for your machine, and change IDENT
to reflect it, and to then put in changes conditionally whenever
this makes sense.
You can be guided by the ERNIE conditional code, which you will
probably want to disable.
.SH
Device drivers
.PP
The UNIX system running is configured to run
with the given disk
and tape, a console, 32 DZ11 lines, 32 DH11 lines,
a Varian printer/plotter, a Versatec printer/plotter, and 2 AMPEX 9300
disks on an EMULEX controller on the UNIBUS.
This is probably not the correct
configuration.
It is easy to correct the configuration information to reflect
the true state of your machine.
For each device driver there
there are certain magic numbers and
configuration parameters kept in header files (suffixed \fB.h\fR) in the
.B conf
directory that you can change.
The device addresses of each device
are defined there, as are other specifications such as the number
of devices.
You should edit each \fB.h\fR file in
.B conf
change them as appropriate for your machine.
.PP
If you have any non-standard device
addresses,
just change the address and recompile.
If the devices's interrupt vector address(es)
are different from those currently known to the system (this is likely),
then the file /usr/src/sys/conf/univec.c must be modified
appropriately: namely, the proper interrupt routine addresses
must be placed in the table `UNIvec'.
Now, make sure you add any new drivers which you have to the list
of DRIVERS in the \fBmakefile\fR in \fBdev\fR,
and to the FILES and CFILES variables in this \fBmakefile\fR and
FILES3 and CFILES3 in \&\fB../sys/makefile\fR.
.PP
As describe in ``Basics of disk layout'' below, the first line of
the makefile in the
.B sys
directory controls the root device and swap disk layout by picking
one of the confhp.c, confup.c, etc. files of the
.B conf
directory. This should be chosed to reflect the desired disk layout
before the system is recompiled.
.SH
Non-integrated device drivers
.PP
As of this date, several device drivers which were available at various
times have not been integrated into the conditional compilation of the
.B dev
and
.B conf
directories.
The source for these device drivers is in the directory
.B /usr/src/sys/newdev.
These device drivers will be made part of
.B /usr/src/sys/dev
and
.B /usr/src/sys/conf
as we have opportunity to test them.
It should not be hard for you to integrate these drivers; if you wish,
you can contact us as we will be able to supply integrated versions very soon.
Here is a list of the drivers which are currently awaiting integration:
.DS
dhdm DM11 modem control driver
kl KL/DL-11 communications driver
lp LP11 line printer driver
rk7 RK07 driver
tm TM11 unibus tape driver
.DE
In addition, there is another
rk07 driver (hk.c).
Code to allow mixing of tapes and disks among and across several MBA's
is also in the works, but is not supplied on this tape.
Contact us if you have need for this code.
.PP
If you integrate these or other drivers we would appreciate receiving
a copy in the mail so that we can avoid duplication of effort. (Other
comments on the system or these instructions are, of course, also welcomed.)
.SH
Makefile entry points
.PP
The
.IR makefile \|s
have several additional useful entry points:
.IP clean 15n
Cleans out the directory, removing
.B \&.o
files and the like.
.IP lint 15n
(In \fBsys\fR) Runs lint on the system.
.IP depend 15n
Creates a new makefile indicating dependencies on header files by
running a search through
.B \&.c
files looking for ``#include'' lines.
Make sure you format your code like the rest of the system so that
this will work.
.IP print 15n
(In \fBsys\fR) Produces a nice listing of most everything in the system
directory in a canonical order.
.IP symbols.sort 15n
(In \fBsys\fR) Creates a new file for sorting symbols in the system namelist.
If you have locally written programs which use the system namelist
you can put the symbols which they reference in
.I symbols.raw
and they will be moved at system generation to the front of the
system namelist for quicker access.
.IP tags 15n
Creates a
.I tags
file for
.I ex,
to make editing of the system much easier.
.SH
Basic constants
.PP
Before running
.I make,
you should check the definition of the constants in
/usr/src/sys/h/param.h
The constants
NBUF, NINODE, NFILE, NPROC, and NTEXT
can be changed, and also TIMEZONE and perhaps HZ if you run on 50 cycles.\(dg
.FS
\(dg If you change NINODE, NFILE, NPROC or NTEXT, then the programs
.IR analyze (1),
.IR ps (1),
.IR pstat (1)
and
.IR w (1)
will have to be recompiled.
A procedure for doing this is given below.
.FE
There are also tunable constants in the file
/usr/src/sys/h/vmtune.h
but ignore them for the time being.
As distributed, the system is tuned for a fairly large machine (i.e. 2+
Megabytes of memory and 2-3 disk arms).
.PP
To generate a completely recompiled UNIX do
.DS
\fB#\fR cd /usr/src/sys/sys
\fB#\fR make clean ; cd ../dev ; make clean ; cd ../conf ; make clean
\fB#\fR cd ../sys
\fB#\fR make depend ; cd ../dev ; make depend ; cd ../conf ; make depend
\fB#\fR cd ../sys
\fB#\fR make \-k > ERRS 2>& 1 &
(compilation will finish about 15 minutes later leaving output in ERRS)
.DE
.PP
The final object file (vmunix) should be
moved to the root, and then booted to try it out.
It is best to name it /newvmunix so as not to destroy
the working system until you're sure it does work.
It is also a good idea to keep the old working version around under some other
name.
A systematic scheme for numbering and saving old versions
of the system is best.
\fBBe sure to always have the current system in /vmunix when you are
running multi-user or commands such as \fIps\|\fR(1)\fB
\fBand\fR \fIw\|\fR(1)\fB will not work.\fR
.SH
Special Files
.PP
Next you should remove any unnecessary device entries from the directory
.B /dev,
as devices were provided for all the things initially configured into
the system.
See how the devices were made using
.B MAKE
in the directory
.B /dev,
and make another directory
.B /newdev,
copy
.B MAKE
into it,
edit
.B MAKE
to provide an entry for local needs,
and rerun it to generate a
.B /newdev
directory.
You can then do
.DS
\fB#\fR cd /
\fB#\fR mv dev olddev ; mv newdev dev
.DE
If you prefer, you can just whittle away at
.B /dev
using
.B rm,
.B mv
and
.IR mknod (8)
to make what you need, but if you do this stuff manually
you may have to do it manually again someday, and the devices
will appear much more ``magic'' to those who follow you.
.SH
Notes on the configuration file and device names
.PP
Print the configuration file
/usr/src/sys/conf/conf.c.
This is the major
device switch of each device class (block and character).
There is one line for each device configured in your system
and a null line for place holding for those devices
not configured.
The essential block special files were installed above;
for any new devices,
the major device number is selected by counting the
line number (from zero)
of the device's entry in the block configuration table.
Thus the first entry in the table bdevsw would be
major device zero.
This number is also printed in the table along the right margin.
.PP
The minor device is the drive number,
unit number or partition as described
under each device in section 4.
For tapes where the unit is dial selectable,
a special file may be made for each possible
selection.
You can also add entries for other devices.
.PP
Each device is typically given several special files in
.B /dev.
The name is made from the name of the device driver, sometimes
varying for historical reasons. Thus the ``up'' disk driver
has disks ``up0a'', ``up0b'', etc., the partitions of drive 0 being
given letters a\-h.
.PP
The tape drives are given names not dependent on the tape driver
hardware, since they are used directly by a number of programs.
The file
.B mt0
is a 1024 byte blocked tape drive at 800 bpi;
.B mt8
is 1600 bpi.
By adding 4 to the unit number you get non-rewinding tapes.
.PP
The disk and magtape drivers provide a `raw' interface
to the device which provides direct transmission
between the user's core and the device and allows
reading or writing large records.
The raw device counts as a character device,
and conventionally has the name of the corresponding
standard block special file with `r' prepended.
Thus the raw magtape
files are called /dev/rmtX.
.PP
The names for terminals should be named
/dev/ttyX, where X is some string (as in `0' or `d0').
While it is possible to use truly arbitrary strings here, the accounting
and noticeably the
.IR ps (1)
command make good use of the fact that tty names
(at Berkeley) are distinct in the last 2 characters. In fact, we use
the following convention:
``ttyN'', with N the minor device number for normal DZ ports;
``ttydX'' with X a single hex digit (starting from 0) for dialups,
``ttyhX'' and ``ttyiX'' with X a hex digit for dh ports,
and ``console'' (abbrev ``co'') for the console.
This works out well and
.IR ps (1)
uses a heuristic algorithm based on these conventions to speed up
name determination from device numbers it otherwise obtains.
.PP
Whenever special files are created,
care should be taken to change
the access modes
.IR (chmod (8))
on these files to appropriate values.
.SH
Basics of Disk Layout
.PP
If
there are to be more filesystems mounted than just the root
and /usr,
use
.IR mkfs (8)
and
.IR mklost+found (8)
to create any new filesystem and
put the information about it into the file
.B /etc/fstab
(see
.IR fstab (5)).
You should look also at /etc/rc to see what commands are executed there
and investigate how
.B fstab
is used.
.PP
Each physical disk drive can be divided into upto 8 partitions; we typically
use only 3 partitions (or 4 on 300M drives). The first partition, e.g.
.B rp0a
is used for a root file system, a backup thereof, or a small file system like
.B /tmp.
The second partition
.B rp0b
is used for paging and swapping.
The third partition
.B rp0g
is used to hold a user file system.
We partition our 300M disks so that almost all of a large disk will
fit onto a 200M disk, just dropping the last partition. This makes
it easier to deal with hardware failures by just copying data.
.PP
There are several considerations in deciding how to adjust the arrangement
of things on your disks:
the most important is making sure there is adequate space
for what is required;
secondarily, throughput should be maximized.
Paging space is an important parameter.
The system
as distributed has 33440 (512 byte) blocks in which to page on the
primary device; additional devices may be provided, with the
paging interleaved between them. This is controlled by entries in
.B /etc/fstab
and in a configuration file in the
.B conf
directory.
.PP
The first line of the
.B makefile
in the
.B sys
directory selects one a file such as
.B confrp.c
in the conf directory.
This file specifies the root and pipe devices and the devices
which are to be used for swapping and paging.
Each device which is to be used for paging (except the primary
one) should be specified as a ``sw'' device in
.B fstab.
.PP
Many common system programs (C, the editor, the assembler etc.)
create intermediate files in the /tmp directory,
so the filesystem where this is stored also should be made
large enough to accommodate
most high-water marks; if you have several disks, it makes
sense to mount this in one of the other ``root'' (i.e. first partition)
file systems.
The root filesystem as distributed is quite large, and there should be
no problem.
All the programs that create files in /tmp take
care to delete them, but most are not immune to
events like being hung up upon, and can leave dregs.
The directory should be examined every so often and the old
files deleted.
.PP
Exhaustion of user-file space is certain to occur
now and then;
the only mechanisms for controlling this phenomenon
are occasional use of
.IR du (1),
.IR df (1),
.IR quot (8),
threatening
messages of the day, and personal letters.
.PP
The efficiency with which UNIX is able to use the CPU
is often strongly affected by the configuration of disk controllers.
For general time-sharing applications,
the best strategy is to try to split the root filesystem (/), system binaries
(/usr), the temporary files (/tmp),
and the user files among several disk arms, and to interleave
the paging activity among a number of arms.
We will discuss such considerations more below.
.SH
Moving filesystem data
.PP
Once you have decided how to make best use
of your hardware, the question is how to initialize it.
If you have the equipment,
the best way to move a filesystem
is to dump it to magtape using
.IR dump (8),
to use
.IR mkfs (8)
and
.IR mklost+found (8)
to create the new filesystem,
and restore (\fIrestor\fR\|(8)) the tape.
If for some reason you don't want to use magtape,
dump accepts an argument telling where to put the dump;
you might use another disk.
Sometimes a filesystem has to be increased in logical size
without copying.
The super-block of the device has a word
giving the highest address which can be allocated.
For relatively small increases, this word can be patched
using the debugger (\fIadb\fR\|(1))
and the free list reconstructed using
.IR fsck (8).
The size should not be increased very greatly
by this technique, however,
since although the allocatable space will increase
the maximum number of files will not (that is, the i-list
size can't be changed).
Read and understand the description given in
.IR filsys (5)
before playing around in this way.
.PP
If you have to merge a filesystem into another, existing one,
the best bet is to
use
.IR tar (1).
If you must shrink a filesystem, the best bet is to dump
the original and restor it onto the new filesystem.
However, this will not work if the i-list on the smaller filesystem
is smaller than the maximum allocated inode on the larger.
If this is the case, reconstruct the filesystem from scratch
on another filesystem (perhaps using \fItar\fR(1)) and then dump it.
If you
are playing with the root filesystem and only have one drive
the procedure is more complicated.
What you do is the following:
.IP 1.
GET A SECOND PACK!!!!
.IP 2.
Dump the root filesystem to tape using
.IR dump (8).
.IP 3.
Bring the system down and mount the new pack.
.IP 4.
Load the standalone versions of
.IR mkfs (8)
and
.IR restor (8)
from the floppy
with a procedure like:
.br
.ne 5
.ID
.nf
\fB>>>\fRUNJAM
\fB>>>\fRINIT
\fB>>>\fRLOAD MKFS
LOAD DONE, xxxx BYTES LOADED
\fB>>>\fRST 2

\&...

\fB>>>\fRH
HALTED AT yyyy
\fB>>>\fRU
\fB>>>\fRI
\fB>>>\fRLOAD RESTOR
LOAD DONE, zzzz BYTES LOADED

\&... etc
.fi
.DE
.IP 5.
Boot normally
using the newly created disk filesystem.
.PP
Note that if you change the disk partition tables or add new disk
drivers they should also be added to the standalone system in
/usr/src/sys/stand.
.SH
System Identification
.PP
You should edit the files:
.DS
/usr/include/ident.h
/usr/include/whoami.h
/usr/include/whoami
/usr/src/cmd/uucp/uucp.h
.DE
to correspond to your system, and then recompile and install
.IR getty (8),
.IR binmail (1),
.IR who (1)
and
.IR uucp (1)
via:
.DS
\fB#\fR cd /usr/src/cmd
\fB#\fR DESTDIR=/
\fB#\fR export DESTDIR
\fB#\fR MAKE getty.c mail.c who.c uucp
.DE
This will arrange for an appropriate banner to be printed on terminals
before users log in, and also arrange that
.I uucp
knows what site you are.
.PP
The program
.IR delivermail (8)
needs to know the topology of your network configuration to be able
to forward mail properly; if you are on any networks
other than
.I uucp
be sure to print the file
.B /usr/src/cmd/delivermail/READ_ME,
edit the appropriate tables, and recompile and install delivermail
as you did
.B uucp
above.
.PP
If you run the Berkeley network
.IR net (1)
be sure to change the constant LOCAL in /usr/src/cmd/ucbmail/v7.local.h
and recompile when you bring up a network machine.
.SH
Adding New Users
.PP
See
.IR adduser (8);
local needs will undoubtedly dictate a somewhat
different procedure.
.SH
Multiple Users
.PP
If UNIX is to support simultaneous
access from more than just the console terminal,
the file /etc/ttys (\fIttys\fR\|(5)) has to be edited.
To add a new terminal be sure the device is configured
and the special file exists, then set
the first character of the appropriate line of /etc/ttys to 1
(or add a new line).
You should also edit the file
/etc/ttytype
placing the type of the new terminal there (see \fIttytype\fR\|(5)).
The file
/etc/ttywhere is also a useful one to keep up to date.
.PP
Note that /usr/src/cmd/init.c and
/usr/src/cmd/comsat.c will have to be recompiled if there are to be
more than 100 terminals.
Also note that if the special file is inaccessible when \fIinit\fR tries to create a process
for it, the system will thrash trying and retrying to open it.
.ne 10
.SH
File System Health
.PP
Periodically (say every week or so in the absence of any problems)
and always (usually automatically) after a crash,
all the filesystems should be checked for consistency
by
.IR fsck (1).
The procedures of
.IR reboot (8)
should be used to get the system to a state where a file system
check can be performed manually or automatically.
.PP
Dumping of the filesystems should be done regularly,
since once the system is going it is very easy to
become complacent.
Complete and incremental dumps are easily done with
.IR dump (8).
You should arrange to do a towers-of-hanoi dump sequence; we tune
ours so that almost all files are dumped on two tapes and kept for at
least a week in most every case. We take full dumps every month (and keep
these indefinitely).
Operators can execute ``dump w'' at login which will tell them what needs
to be dumped
(based on the
.B fstab
information).
Be sure to create a group
.B operator
in the file
.B /etc/group
so that dump can notify logged-in operators when it needs help.\(dg
.FS
\(dg More precisely, we have three sets of dump tapes: 10 daily tapes,
5 weekly sets of 2 tapes, and fresh sets of three tapes monthly.
We do daily dumps circularly on the daily tapes with sequence
`3 2 5 4 7 6 9 8 9 9 9 ...'.
Each weekly is a level 1 and the daily dump sequence level
restarts after each weekly dump.
Full dumps are level 0 and the daily sequence restarts after each full dump
also.
Thus a typical dump sequence would be:
.TS H
c c c c c
n n n l l.
tape name level number date opr size
_
.TH
FULL 0 Nov 24, 1979 jkf 137K
D1 3 Nov 28, 1979 jkf 29K
D2 2 Nov 29, 1979 rrh 34K
D3 5 Nov 30, 1979 rrh 19K
D4 4 Dec 1, 1979 rrh 22K
W1 1 Dec 2, 1979 etc 40K
D5 3 Dec 4, 1979 rrh 15K
D6 2 Dec 5, 1979 jkf 25K
D7 5 Dec 6, 1979 jkf 15K
D8 4 Dec 7, 1979 rrh 19K
W2 1 Dec 9, 1979 etc 118K
D9 3 Dec 11, 1979 rrh 15K
D10 2 Dec 12, 1979 rrh 26K
D1 5 Dec 15, 1979 rrh 14K
W3 1 Dec 17, 1979 etc 71K
D2 3 Dec 18, 1979 etc 13K
FULL 0 Dec 22, 1979 etc 135K
.TE
We do weekly's often enough that daily's always fit on one tape and
in fact never get to the sequence of 9's in the daily level numbers.
.FE
.PP
Dumping of files by name is best done by
.IR tar (1)
but the number of files is somewhat limited.
Finally if there are enough drives entire
disks can be copied with
.IR dd (1)
using the raw special files and an appropriate
block size.
.SH
Converting 32/V Filesystems
.PP
The best way to convert filesystems from 32/V
to the new format
is to use
.IR tar (1).
After converting, you can still restore files from your old-format dump
tapes (yes the dump format is different, sorry about that), by using
``512restor'' instead of ``restor''.
If you wish, you can move whole file systems from 32/V to the new system
by using ``dump'' and then ``512restor''.
.SH
Regenerating the system
.PP
It is quite easy to regenerate the system, and it is a good
idea to try this once right away to build confidence.
The system consists of three major parts:
the kernel itself (/usr/src/sys/sys), the user programs
(/usr/src/cmd and subdirectories), and the libraries
(/usr/src/lib*).
The major part of this is /usr/src/cmd.
.PP
We have already seen how to recompile the system itself.
The three major libraries are the C library in /usr/src/libc
and the \s-2FORTRAN\s0 libraries /usr/src/libI77 and /usr/src/libF77. In each
case the library is remade by changing into the corresponding directory
and doing
.DS
\fB#\fR make
.DE
and then installed by
.DS
\fB#\fR make install
.DE
Similar to the system,
.DS
\fB#\fR make clean
.DE
cleans up.
The source for all other libraries is kept in subdirectories of
/usr/src/lib; each has a makefile and can be recompiled by the above
recipe.
.PP
Recompiling all user programs in /usr/src/cmd is accomplished by using
the MAKE shell script which resides there and its associated file
DESTINATIONS.
For instance, to recompile ``date.c'',
all one has to do is
.DS
\fB#\fR cd /usr/src/cmd
\fB#\fR MAKE date.c
.DE
this will place a stripped version of the binary of ``date''
in /4bsd/bin/date, since date normally resides in /bin, and
Admin is building a file-system like tree rooted at /4bsd
You will have to make the directory 4bsd for this to work.
It is possible to use any directory for the destination, it isn't necessary
to use the default /4bsd; just change the instance of ``4bsd''
at the front of MAKE.
.PP
You can also override the default target by doing:
.DS
\fB#\fR DESTDIR=\fIpathname\fR
\fB#\fR export DESTDIR
.DE
.PP
To regenerate all the system source you can do
.DS
\fB#\fR DESTDIR=/usr/newsys
\fB#\fR export DESTDIR
\fB#\fR cd /usr
\fB#\fR rm \-r newsys
\fB#\fR mkdir newsys
\fB#\fR cd /usr/src/cmd
\fB#\fR MAKE * > ERRS 2>& 1 &
.DE
This will take about 4 hours on a reasonably configured machine.
When it finished you can move the hierarchy into the normal places
using
.IR mv (1)
and
.IR cp (1),
and then execute
.DS
\fB#\fR DESTDIR=/
\fB#\fR export DESTDIR
\fB#\fR cd /usr/src/cmd
\fB#\fR MAKE ALIASES
\fB#\fR MAKE MODES
.DE
to link files together as necessary and to set all the right set-user-id
bits.
.SH
Making orderly changes
.PP
In order to keep track of changes to system source we migrate changed
versions of commands in /usr/src/cmd in through the directory /usr/src/new
and out of /usr/src/cmd into /usr/src/old for a time before removing them.
Locally written commands which aren't distributed are kept in /usr/src/local
and their binaries are kept in /usr/local. This allows /usr/bin /usr/ucb
and /bin to correspond to the distribution tape (and to the manuals that
people can buy). People wishing to use /usr/local commands are made
aware that they aren't in the base manual. As manual updates incorporate
these commands they are moved to /usr/ucb.
.PP
A directory /usr/junk to throw garbage into, as well as binary directories
/usr/old and /usr/new are very useful. The man command supports manual
directories such as /usr/man/manj for junk and /usr/man/manl for local
to make this or something similar practical.
.SH
Interpreting system activity
.PP
The
.I vmstat
program provided with the system is designed to be an aid to monitoring
systemwide activity. Together with the
.IR ps (1)
command (as in ``ps av''), it can be used to investigate systemwide
virtual activity.
By running
.I vmstat
when the system is active you can judge the system activity in several
dimensions: job distribution, virtual memory load, paging and swapping
activity, disk and cpu utilization.
Ideally, there should be few blocked (B) jobs,
there should be little paging or swapping activity, there should
be available bandwidth on the disk devices (most single arms peak
out at about 30-35 tps in practice), and the user cpu utilization (US) should
be high (above 60%).
.PP
If the system is busy, then the number of active jobs may be large,
and several of these jobs may often be blocked (B). If the virtual
memory is very active, then the paging demon may be running (SR will
be non-zero). It is healthy for the paging demon to free pages when
the virtual memory gets active; it is triggered by the amount of free
memory dropping below a threshold and increases its pace as free memory
goes to zero.
.PP
If you run
.I vmstat
when the system is busy (a ``vmstat 5'' is best, since that is how
often most of the numbers are recomputed by the system), you can find
imbalances by noting abnormal job distributions. If a large number
of jobs are blocked (B), then the disk subsystem
is overloaded or imbalanced. If you have a large number of non-dma
devices or open teletype lines which are ``ringing'', or user programs
which are doing high-speed non-buffered input/output, then the system
time may go very high (60-70% or higher).
It is often possible to pin down the cause of high system time by
looking to see if there is excessive context switching (CS), interrupt
activity (IN) or system call activity (SY). Cumulatively on one of
our large machines we average about 60 context switches and interrupts
per second and about 90 system calls per second.
.PP
If the system is very heavily loaded, or if you have very little memory
relative to your load (1M is little in most any case), then the system
may be forced to swap. This is likely to be accompanied by a noticeable
reduction in system performance as the system does not swap ``working
sets'', but rather forces jobs to reinitialize their resident sets
by demand paging. If you expect to be in a memory-poor environment
for an extended period you might consider administratively limiting system
load, and should be sure to downsize the system.
.SH
Tunable constants
.PP
There is a modicum of tuning available in the virtual memrory management
mechanism if it appears to be badly tuned for your configuration.
The page replacement (clock) algorithm is run whenever there are
not LOTSFREE pages available
(this and all other constants discussed here are defined in the system
header file /usr/src/sys/h/vmtune.h).
This sets up resistance to consumption of the remaining free memory
at a minimal rate SLOWSCAN, which gives the desired number of seconds
between successive examinations of each page. The rate at which the clock
algorithm is run increases linearly to a desired rate of FASTSCAN when
there is no free memory. Thus as the available free memory decreases,
the clock algorithm works harder to hold on to what is left.
If less than DESFREE pages are available and the paging rate is high,
then the system will begin to swap processes out. If less than MINFREE
pages are available then the system will begin to swap, regardless of the
paging rate.
.PP
When it has to swap, the system first tries to find a process which has
been blocked for a long time and swap it out first. If there are no
jobs of this flavor, then it will choose among the 4 largest jobs in-core
which it can swap, picking the one of these which has been core resident
longest. It attempts
to guarantee (during periods of very heavy load) enough core residency to
a process to allow it to at least rebuild its set of active pages (since
it must do so by demand paging). Processes which are swapped out
with large numbers of active pages similarly receive lower priority for
swapin, favoring small jobs to return to the core resident set quickly.
.PP
It is
.I very
desirable that the system run under reasonably heavy load with little
swapping, with the memory partitioning being done by the clock replacement
algorithm, rather than by the swapping algorithm. The costs associated
with paging activity are the time spent in the paging demon, the overhead
associated with reclaim page faults (RE), and the extra disk activity
associated with pagins and pageouts.
We will discuss disk considerations later; when kept to about 40 reclaim
faults per second, the cost of reclaims is less than 1% of total processor
time. The cpu time (shown by ``ps u2'') accumulated by the pageout demon
will show how much overhead it is generating.
.PP
The system, as distributed, runs the replacement algorithm whenever less
than 1/4 of the total user memory is free.
This is done starting with a 25 second revolution time of the clock
algorithm and increasing to a 15 second revolution time when there is no
free memory.
The goal here is to use as much memory as possible (i.e. have the
free list short) but to not have the system run out and start to swap.
You can experiment with changing the writable copies of these variables
(e.g. ``lotsfree'' is the writable copy of LOTSFREE) using
.I adb,
as in:
.DS
\fB#\fR adb \-w /vmunix /dev/kmem
lotsfree/D
---adb prints value of lotsfree---
/W 0t100
.DE
Here the ``/W 0t100'' command changed the value of
.I lotsfree
to be 100 (decimal).
.PP
One final constant which can be changed is
.B klin
which controls the page-in clustering in the system.
As distributed, it is set to 2, which allows the system to pre-page
a even numbered (1k byte) page when an odd numbered page is faulted
and vice-versa. In extreme circumstances, for special purpose applications
which cause heavy paging activity you might try setting it to 4 to increase
the amount of pre-paging,
allowing the system to pre-page up to 3 adjacent pages.
This will increase the rate at which memory is consumed on an active
system, so you should be aware that this can
overload the page replacement mechanisms ability to maintain enough free
memory and can thus cause swapping.
With this volume of page traffic it may be necessary to set the global constant
.B fifo
to 1 in the system, causing the paging algorithm to ignore page-referencing
behavior and favoring, rather, circular replacement.
.PP
.B Klin
should be changed only experimentally on systems with abnormal
amounts of paging activity. This is not necessary or appropriate for
most any normal timesharing load.
.SH
Balancing disk load
.PP
It is critical for good performance to balance disk load.
There are at least five components of the disk load which you can
divide between the available disks:
.DS
1. The root file system.
2. The /tmp file system.
3. The /usr file system.
4. The user files.
5. The paging activity.
.DE
The following possibilities are ones we have actually used at times
when we had 2, 3 and 4 disks:
.TS
center doublebox;
l | c s s
l | lw(5) | lw(5) | lw(5).
disks
what 2 3 4
_
\fB/\fR 1 2 2
tmp 1 3 4
usr 1 1 1
paging 1+2 1+3 1+3+4
users 2 2+3 2+3
archive x x 4
.TE
.PP
Splits such as these should get you going.
The most important things to remember are to
even out the disk load as much as possible, and to do this by
decoupling file systems (on separate arms) between which heavy copying occurs.
Note that a long term average balanced load is not important... it is
much more important to have instantaneously balanced
load when the system is busy.
.PP
Intelligent experimentation with a few file system arrangements can
pay off in much improved performance. It is particularly easy to
move the root, the
/tmp
file system and the paging areas. Place the
user files and the
/usr
directory as space needs dictate and experiment
with the other, more easily moved file systems.
.SH
Process size limitations
.PP
As distributed, the system provides for a maximum of 64M bytes of
resident user virtual address space. The size of the text, and data
segments of a single process are currently limited to 6M bytes each, and
the stack segment size is limited to 512K bytes as a soft, user-changeable
limit, and may be increased to 6M by calling
.IR vlimit (2).
If these are insufficient, they
can be increased by changing the constants MAXTSIZ, MAXDSIZ and MAXSSIZ
in the file
/usr/src/sys/h/vm.h, while
changing the definitions in
/usr/src/sys/h/dmap.h and /usr/src/sys/h/text.h.
You must be careful in doing this that you have adequate paging space.
As configured above, the system has only 16M bytes of paging area,
since there is only one paging area. The best way to get more
space is to provide multiple, thereby interleaved, paging areas
by using a file other than confhp.c; see the first line of the makefile
in the sys directory and the disk layout section above.
.PP
To increase the amount of resident virtual space possible,
you can alter the constant USRPTSIZE (in
/usr/src/sys/h/vm.h)
and by correspondingly change the definitions of
.I Usrptmap
in
/usr/src/sys/sys/locore.s
Thus to allow 128 megabytes of resident virtual space one would
declare
.DS
_Usrptmap: .space 16*NBPG
.DE
.PP
The system has 6 pages of page tables for its text+data+bss areas and the
per-page system information. This limits this part of the system
to 6*64K = 384K bytes. The per-page system information uses 12 bytes
per 1024 bytes of user available physical memory. This (conservatively)
takes 55K bytes on a 4 megabyte machine, limiting the ``size''
of the system to about 330K bytes. You can increase the size of the system
page table to, for example, 8 pages by defining, in locore.s:
.DS
_Sysmap: .space 8*NBPG
.DE
You will then also have to change the definitions of the constants
UBA0, MBA0, and MBA1 in the files
.B uba.h
.B mba.h,
.B mba.m,
and
.B uba.m.
The 6 in the numbers here is the 6 from the number of pages in
.I Sysmap
thus UBA0 would then be defined by
.DS
\fB#define UBA0 0x80080000\fR
.DE
.PP
You should also change the constant RELOC in the bootstrap programs in
.B /usr/src/sys/stand
to be large enough to relocate past the end of the system.
.IR Grep (1)
for RELOC
in this directory and change the constants, recompile the bootstrap
programs and replace them on the floppy.
.SH
Other limitations
.PP
Due to the fact that the file system block numbers are stored in
page table
.B pg_blkno
entries, the maximum size of a file system is limited to
2^20 1024 byte blocks. Thus no file system can be larger than 1024M bytes.
.PP
The number of mountable file systems is limited to 15 (which should
be enough; if you have a lot of disks it makes sense to make some of
them single file systems, and the paging areas dont count in this total.)
To increase this it will be necessary to change the core-map
/usr/src/sys/h/cmap.h since there is a 4 bit field used here. The size
of the core-map will then expand to 16 bytes per 1024 byte page and you should
change /usr/src/sys/h/cmap.m also. (Don't forget to change MSWAPX and
NMOUNT in /usr/src/sys/h/param.h also.)
.PP
The maximum value NOFILE (number of open files per process) can be raised to
is 30 because of a bit field in the page table entry in
.B /usr/src/sys/h/pte.h.
.SH
Scaling down
.PP
If you have 1.5M byte of memory or less you may wish to scale the
paging system down, by reducing some fixed table sizes not directly
related to the paging system.
For instance, you could reduce NBUF from 128 to 40, NCLIST from 500 to 150,
NPROC from 250 to 125, NINODE from 400 to 200, NFILE from 350 to 175,
NMOUNT from 15 to 8, and NTEXT from 60 to 40.
You can use
.IR pstat (8)
with the \fB\-T\fR option
to find out how much of these structures are typically in use.
Although the document is somewhat outdated for the \s-2VAX\s0,
you can see the last few pages of ``Regenerating System Software''
in Volume 2B of the programmers manual for hints on setting some of these
constants.
.ne 10
.SH
Files which need attention
.PP
The following files require periodic attention or are system specific
.de BP
.IP \fB\\$1\fR
.br
..
.TS
center;
lb a.
/etc/fstab how disk partitions are used
/etc/group group memberships
/etc/motd message of the day
/etc/passwd password file; each account has a line
/etc/rc system restart script; runs reboot; starts daemons
/etc/ttys enables/disables ports
/etc/ttytype terminal types corrected to ports
/etc/ttywhere lists physical locations of terminals
/usr/lib/crontab commands which are run periodically
/usr/lib/mailaliases mail forwarding and distribution groups
/usr/adm/acct raw process account data
/usr/adm/dnacct raw autodialer account data
/usr/adm/messages system error log
/usr/adm/wtmp login session accounting
.TE
.SH
Thats all for now.
.PP
Good luck.
.in +4i
.sp 2
William N. Joy
.br
Ozalp Babaoglu
.br
Keith Sklower