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February 1985

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Feb 85

TSX-PLUS USER'S GROUP NEWSLETTER

February 1985
Administration

Newsletter

TSXPUG
c/o Glenn Burnett
Zia Corporation
P.O. Box 351
Morris Plains, NJ

TSXPUG
c/o Jack Peterson
Horizon Data Systems
1901 Wildflower Terr.
Richmond, VA 23233

decided to copyright each issue of our
newsletter. We have become aware of a few
instances in the past where
material
published herein has been copied without
acknowledgement and used for commercial
advantage.
This is unfair to the volunteers who provide material for the newsletter, and unfair to our members who pay
good money to receive it.
Feel free to
use whatever information we provide to the
greatest extent possible, but if you steal
it and distribute -Lt to others, you are
breaking a law which imposes severe cIvil
and/or criminal penalties.

BOILERPLATE!
Welcome to this, the fifth issue of our
newsletter published by the TSX-Plus Users
Group (TSXPUG), a volunteer organization
dedicated to the exchange of information
among users of TSX-Plus. TSXPUG is independent
of and receives no financial
support from S & H; expenses are paid from
The newsletter is premembership dues.
pared four times a year (February, May,
August,
and November) and mailed the
following month.
Jack and Glenn, whose addresses are above,
run TSXPUG..
Jack writes and edi ts the
newsletter; Glenn handles administration,
collecting dues, maintaining the membership list, and mailing the newsletter. If
you have a contribution for the newsletter, please write to Jack; direct other
correspondence to Glenn.

MEMBERSHIP RENEWAL INFORMATION
All of you should have received a mem~.i.r.ship renewal notice.
If you have ~. )
please notify Glenn immediately.
Beca~se
this was the first time we went through
the renewal process, we were a little late
getting the notices out, so everyone is
receiving a copy of this issue.
The
remalnlng three issues this year will go
only to those who renew for 1985. We must
receive your renewal before May 1 if you
expect to receive the next issue.

Brief newsletter stuff may be submitted in
hardcopy form, but we prefer
lengthy
articles on magnetic media. We can read
RX01, RX02, and 1600 bpi magnetic tape; in
a pinch, RX50 and RL02; in a real pinch,
RL01. We will return media to you if you
ask us to do so. Thanks for your cooperation and your contributions.

USA and Canadian memberships are US$15.00
per year, US$20.00 per year in all other
countries. We request foreign subscribers
to remit in US$ with an instrument (such
as an international money order) payable
at a bank in the United States to avoid
delays and service charges.

IMPORTANT NOTICE!
This newsletter is published by the TSXPlus Users' Group for distribution to and
use of its members only. Duplication of
this newsletter without the express written permission of Horizon Data Systems is
prohibited. Copyright (C) 1985 by Horizon
Data Systems. ALL RIGHTS RESERVED.
As

you

can

see

the

07950

CONSULTANT HOTLINE
Two more firms have told us they provide
TSX-Plus consulting services, bringing the
total to five. The latest entries are:

above, we have
-1-

TSX-Plus User's Group Newsletter
February 1985
Peter Heinicke
Precision Computer Methods, Inc.
No. 3 2S119 Winchester Circle
Warrenville, TL 60555
(312) 393-6418
Milton D. Campbell
Talisman Systems
Drawer CP-255
Manhattan Beach, CA 90266
(213) 318-2206
If there are more of you out there, please
let us know. We will publish a summary of
all known TSX-Plus consultants in the next
issue.

DECUS NEWS
The Fall 1984 DECUS Symposium was held at
the Anaheim Convention Center in December.
Several items of interest to TSX-Plus
users emerged from this meeting. With the
help of Ned Rhodes, we were able to schedule a TSXPUG Birds of a Feather (BOF)
session and a TSX-Plus Magic panel discussion.
Both were well attended and well
received; they will be featured again in
New Orleans.
DEC announced RT-11 Version 5.2 (scheduled
for April or May) and BASIC Version 3.0
(scheduled for June). The former appears
to be of little interest to TSX-Plus
users, but the new BASIC version, a superset of BASIC-Plus 2, has been long awaited.
BASIC V3.0 will be distributed as a
new release of BASIC-11 rather than as a
new product, so if you have BASIC support,
you will receive this new version automatically when it is released.
The Spring 1985 DECUS Symposium will be
held in New Orleans, May 21 - 31. Several
presentations
related to TSX-Plus are
planned. Two pre-Symposium seminars will
be offered, one on RT-11 internals, one on
IND. Seminars are all-day affairs held
the Sunday before Symposia open (May 26 in
this case), cost extra bucks beyond the
Symposium tab 1 and are conducted only if
enough people sign up. If you are interested in either of these, check your
Symposium registration packet for
the
application.

There are many RT-11 presentations scheduled for New Orleans, at least 7 of which
are of special interest to TSX-Plus users.
Tom Shinal of General Scientific will
present "The RT-11/TSX Office", a reprise
of a good presentation given in Anaheim,
on Wednesday from 1:30pm to 2:30pm.
Jack Peterson will chair two audience
participation sessions. The first, Tuesday from 5:30pm to 7:00pm, is "TSX-Plus
Magic", which explores problems, solutions, tricks, and workarounds for TSXPlus.
The second, Wednesday from 3:30pm
to 4:45pm, is new, a "Third-Party RT-11
Application Software Forum" which permits
users (not salesmen) to recount their
experiences, good or bad, with third-party
RT-11/TSX-Plus software. If you have such
experiences you wish to share, or if you
are considering purchasing a
software
package, come to this session and participate and/or learn from others.
Bob Manfredi of the University of Connecticut Health Center will present two very
interesting papers. On Monday from 9:00pm
to 10:30pm, Bob \.[i11 discuss "TSX-P1us In
The Laboratory", showing application of
several TSX-Plus special features including shared run-time systems, PLAS support,
job monitoring, record locking, and user
interrupt processing.
On Tuesday, from
4:30pm to 5:30pm, he will present a "User
Written Keyboard Monitor (KMON) for TSXPlus"
which provides many interesting
features including I/O redirection, pipes,
User Command Linkage (UCL), and other
goodies.
On Monday, from 8:30pm to 9:30pm, James
Phelps
and Harvey Cohen will discuss
"TSX/FORTRAN Real-Time", a set of realtime routines they have developed for use
under TSX. Last, and certainly not least,
on T1Jesday , f~om 3: 30pm to 4: 30pm, Phi 1
Sherrod of S & H will present "TSX-Plus
Scheduling Internals and System Tuning", a
paper of great interest to system managers.
Concurrently with DEGUS, New Orleans will
host the DEXPO trade show which affords an
excellent opportunity to see, hear, smell,
and touch lots of DEC compatible hardware

TSX-Plus User's Group Newsletter
February 1985
Robert Schor
Rockefeller University
1230 York Avenue
New York NY 10021
212-510-8600

and software. DEXPO will be at the New
Orleans Superdome Tuesday through Friday.
The show's sponsors promise about 300
exhibitors who will collectively display
500 new hardware and software products.
DEXPO is open to all DECUS attendees at no
additional cost, but you must register
separately for this event, which is not
affiliated in any way with DEC or DECUS.
We suggest you use the preregistration
forms found in DEXPO flyers and ads to
avoid long lines at the show.

Paul A. Kessler
Brookhaven National Lab
AMD Building 515
Upton NY 11913
516-282-4156
Dennis P. Costello
Cornell University
National Submicron Lab
602 Knight Lab
Ithaca NY 14853
601-256-2329

All in all, New Orleans looks like a good
bet in a great town! We hope to see you
there.
RT-11 SYMPOSIUM TAPE TREE

John F. Stitzinger
HRB Singer
Science Park Road

Speaking of DECUS, Tom Shinal, who distributes RT-11 Symposia tapes, has created a
new tape distribution tree. According to
his scheme, Ralston Barnard creates the
master tape, usually within two weeks
after Symposium, and provides a copy to
Tom, who enters it into his distribution
tree.
The tree has 43 nodes and a depth
of 5, so within a few more weeks, all
nodes should have a copy of the tape for
distribution to end users.

D/115

P.O. Box 60
State College PA 16801
814-238-4311 X2853
Thomas J. Shinal
General Scientific Corp.
1684 East Gude Drive
Rockville MD 20850
301-340-2112

This tree is run by the RT-ll SIG rather
than the National LUG Organization, who
have an independent tree. If you belong
to a LUG, please get your copy from it.
Otherwise, follow
two
simple
steps.
First, from the list below, select the
node WHOSE ZIP CODE IS CLOSEST TO YOUR
OWN.
Then, forward a 2400-ft mag tape
reel, appropriate postage
and
return
addressing information, and a clear statement of what you want (Spring 1985 RT-l1
Symposium Tape, for example). Sit back
and wait for your copy to arrive.
These
people
do this work as uncompensated
volunteers, so please follow the rules to
make their job as easy as possible.

Robert E. Langford
Medical College of Va.
Room B3-016
1101 E. Marshall Street
Richmond VA 23298
804-186-9843
R.H. Klausewitz
West Virginia Wesleyan
Computer Center
Buckhannon WV 26201
304-412-9520
Janet Anderson
Rockwell International
Suite 200
800 Eastowne Drive
Chapel Hill NC 21514
914-968-4836

The following is a list of all nodes in
the tree, in zip code order. PLEASE SAVE
THIS LIST. WE WILL NOT REPEAT IT, EXCEPT
FOR CHANGES, THIS YEAR.

-3-

TSX-Plus User's Group Newsletter
February 1985
Herbert Spies
ADIKRESS
Building 380
Eglin AFB FL 32542
904-882-5498

Rick Sharpe
Toledo Edison

MIS 3085
300 Madison
Toledo OH 43652
415-259-3000 X470

Michael Newell
Florida Inst of Technology
150 W. University Blvd.
Melbourne FL 32901
305-768-8101

Tom Haase
SORIO
4440 Wanersville Ctr
Cleveland OR 44128
216-581-5724

Mike Minton
NOAA
Atl Ocean & Metro Lab
4301 Rickenbacker Causeway
Miami FL 33149
305-361-4356

Marion M. Fauber

MIS 4-07
P.O. Box 1042
Dayton OR 45401
513-258-7707

Amanda F. Stokes
Teledyne Brown Engineering
Cummings Research Park
Huntsville AL 35807
205-532-1842

Kreigh Tomaszewski
Amway Corporation
21A-2D
7575 East Fulton Road
Ada MI 49355
616-676-7402

Dan Tipton
ORFMA
117 Flint Road
Oak Ridge TN 37830
615-482-5000

Jim Flatten
Ames Laboratory
304 Metallurgy
Ames IA 50011
515-294-4823

Jerry W. Ethington
Federal Land Bank
201 W. Main Street
P.O. Box 32390
Louisville KY 40232
502-566-7304

Ed McGuire
Grinnell College
Computer Services
Grinnell IA 50112
515-236-2570

Daryl George
Ohio Wesleyan University
Dept. of Math Sciences
Delaware OH 43015
614-369-4431 X900

Mark Buda
12000 We Park Place
Milwaukee WI 53224
414-359-9800

Laurence G. Owens
Owens Computer Services
2813 Indianola Avenue
Columbia OH 43202
614-262-4805

John Vilandre
University of Minn.
Div. of Epidemiology
Stadium Gate 27
Minneapolis MN 55455
612-376-4056
Jim Leedham
Mayo Foundation
200 1st Street SW
Rochester MN 55905
507-284-2620

-4-

TSX-Plus User's Group Newsletter
February 1985
Dale J. Travis
Argonne National Lab
D817
9700 S. Cass Avenue
Argonne IL 60439
312-972-6964

Ralston W. Barnard
Sandia National Labs
Nuclear Physics 7523
Albuquerque NM 87185
505-844-5115
Nick Bourgeois
NAB Software Services
3236 Candlelight NE
P.O. Box 20009
Albuquerque NM 87154
505-298-2346

Frank Talaga
Univ of Illinois
College of Dentristy
MIC 621 - Room 504
801 S. Pailina
Chicago IL 60612
312-996-7520

James F. Harrison
Los Alamos National Lab
MP-1 MIS H810
Los Alamos, NM 87545
505-667-5688

Richard Wrenn
Washington University
Dept. of Chemistry
Campus Box 8094
St. Louis MO 63110
314-362-3354

Doug Gladden
White Sands Missile Range
NR-AD-A
WSMR NM 88002
505-678-3348

Robert Fairchild
Nebraska Wesleyan Univ.
50th & St. Paul
Lincoln NE 68504
402-466-2371

Clifford P. Lloyd
MIS C-81
P.O. Box 1912
Las Vegas NV 89125
702-295-0392

Guy Dunbar
Wm. E. Davis & Sons, Inc.
37 NW 122nd Street
Oklahoma City OK 73114
405-751-4660

Dr. Jeffrey P. Lieb
REED NRC
UCLA
Los Angeles CA 90024
213-825-6713

Bruce D. Sidlinger
ALCOR Inc.
10130 Jones Maltsberger Rd.
P.O. Box 32516
San Antonio TX 78284
512-349-3711

Jim Harnm
Boschert Inc.
384 Santa Trinita
Sunnyvale CA 94088
408-732-2440

David Taft
USGS
Box 25046 MIS 978
Denver Federal Center
Denver CO 80225
303-236-1639

Kevin Douglas Walker
Unitek Electronics Inc.
Suite 222
2850 Paa Street
Honolulu HI 96819
808-836-0877
Robert Perry
Tektronix Inc.
MIS 19-333
Box 500
Beaverton OR 97077
503-627-5410

-5-

TSX-Plus User's Group Newsletter
February 1985
assert this signal whenever the three
highest bits of a (18-bit) DMA address are
all ones, causing a reference to the 1/0
page rather than to memory.

Ron Tenison
The Catlin Gabel School
8825 SW Barnes Road
Portland OR 97225
503-297-1894

I/O requests made to a MAPIO device when
the user buffer is located totally within
the first 256K bytes of memory are processed normally by TSX-Plus, i.e., internal mapping buffers are not used. If,
however, a buffer extends beyond 248K,
some third-party devices may assert BBS7 L
during DMA operations.
The
technical
support group at S & H is addressing this
issue; perhaps we will have a fix in the
next newsletter.

Steve Loretzen
UNICOMP Corporation
500 Fourth & Battery Bldg
Seattle WA 98121
206-223-6453
FORK1N' (The Bug Killer)
Stan Montz of Murry Bergtraum High School
in New York had a problem using a T1-855
serial printer under the LS handler mentioned in the last issue: He has subsequently written to tell us he found the
solution. He had inadvertently genned the
serial printer port as a time-sharing line
also, which causes conflicts over who owns
the interrupt vectors.

HINTS AND KINKS
by
Ned W. Rhodes
Software Systems Group
1684 East Gude Drive
Rockville, MD. 20850
(301) 340-2773

Tf you want to use a serial port sometimes
Jr a printer and sometimes for a timesharing line, gen the port as a time
sharing line and allocate at least one
extra (unattached) CL unit by setting
TSGEN parameter CLXTRA to the number of
extra units desired.
The port normally
functions as a time-sharing line.
To
seize the line for use as a printer, use
the SET CLx LINE=nn command (see TSX-Plus
Reference Manual for details).

Welcome to what may become a regular
column in the TSXPUG Newsletter. Both Tom
Shinal (General Scientific) and I will be
contributing items to the column. Two
things motivated me to start this column.
The first was that, as a consultant, 1 am
called in to help with some unusual TSX
problems.
As a result, I see some things
I cannot explain easily.
So, in this
column, I hope to share these unusual
events with you; perhaps some of you have
experienced the same problems and/or have
developed fixes or workarounds.
When 1
have a workaround, I will publish it here.
If you have a workaround to an unusual
problem, please write or call me, and I
will pass it along in the next column.

Also mentioned in the last issue was a
problem Bill Leroy had using an l8-bit
third-party tape drive (MT handler) in a
22-bit system. Bill specified MAPIO for
the handler, but jobs running above 256K
frequently crashed when accessing tape.
Locking tape jobs into low memory solved
the problem. Since this item was published, several rA8ders have indicated
similar problems with other foreign l8-bit
peripherals.

The second reason for this column?
I
can't stand to see Jack have all the fun
doing this newsletter.

This problem may be due to strange implementations of the QBUS protocol by some
"hird-party devices.
When an 1/0 page
eference is made by a ~us master device,
it is supposed to assert signal BBS7 L.
We think some third-party devices may

DY Problems
Our first problem concerns floppy disks.
We have experienced frequent "Trap to 4"
errors when copying large flIes to our

-6-

TSX-Plus User's Group Newsletter
February 1985
floppies under heavy system load. We use
third-party floppy disk
systems
with
l8-bit controllers, and have tried both
MAPIO and our own data forwarding handlers
to enable operation in 22-bit systems, but
the errors persist. By trial and error,
we learned that using the ISLOWLY option
on our COpy commands, or locking PIP, DUP,
and DIR in low memory, eliminates the
problem.

by printing on one CL port while runnion
VTCOM on another. Running three pr-in t·~
simultanously without VTCOM works fine, .
does any combination if VTCOM is not very
busy (transfering a file, for example).
Has anyone else experienced this problem?
[Editor's Note: Apparently, some other
people have. This problem has been recognized by S & H and is corrected in Version
5.1C, now in field test.]

There are two ways to lock programs into
low memory.
You can modify the program
itself to issue the "lock into low memory"
TSX-Plus EMT, or you can edit TSGEN.MAC to
add a program name to the list of programs
requlrlng special attention when run by
TSKMON. This list is located at label
SRFPRG outside the section of TSGEN.MAC
where user changes are normally made.
To
lock PIP, DUP, and DIR in low memory, add
each to this list of programs, specifying
the AF$MEM flag.

The Lost System
The Lost System is our final problem for
this issue. You encounter this problem
when you
run a program that normally
works but it now traps, or you copy a file
to another device but the copy is now
garbage. We suspected a directory caching
bug, so S & H supplied a feature patch to
disable automatic directory caching of SY
and to allow SY to be DISMOUNTed. With
these patches installed, our systems don't
get lost anymore.

At this time, we do not know the cause of
our problem, but as the FORKIN' column
above points out, this may be caused by
improper device operatIon in the 248K to
256K address range. We, Jack, and S & H
are actively pursuing this possibility,
and will let you know what we discover in
the next newsletter.

Rather than publish the patches here, ~
will contInue to look at the problem.
~
anyone has seen this problem, please get
in touch with me so we can compare notes.
And Finally

MT/MS Problems

I hope there was something of interest for
you in this column. Feel free to contact
me with unusual TSX-Plus problems that may
be of interest to others. For routine
problems, contact your distributor or hire
one of the consultants mentioned in the
CONSULTANT HOTLINE (like me).

We have two problems with our magnetic
tape
drives,
also third-party l8-bit
devices. The first problem, similar to
that above, is copy failure under heavy
system load.
We have also noted the
INITIALIZE command sometimes moves tape
and appears to work properly, but the tape
remains uninitialized. This problem also
disappears by locking DUP in low memory.
Again, we are not sure why this happens,
but we suspect it is related to the problem above.
I would be interested in
hearing from you if you are experiencing
similar problems.

LOGICAL DISKS - A TUTORIAL
Readers have occasionally requested that
we include brief tutorials on certain
facets of TSX-Plus operation in
this
newsletter. Most recently, several people
have requested information on
logical
disks and the LD handler. As an experiment, we have prepared an introduction tQ
this subject.
If you would like to s~
other such columns as a regular newslett~
feature, let us know what topics you would

CL Problems
Our system is configured with two dial-in
lines and three printer ports, all driven
by the CL handler. We can hang our system

-7-

TSX-Plus User's Group Newsletter
February 1985

'i.ke discussed.
Better yet, offer to
i te one for us. We may consider paying
a small honorarium ($25.00 to $50.00) for
each one published.

CREATE DM2:MYDISK.DSK/ALLOC:2000
MOUNT LDO DM2:MYDISK
INIT/NOQ LDO:
If you examine the directory of LDO, you
will see that it has 1986 free blocks.
Where dId the missing 14 blocks go?
A
logical disk has the same characteristics
as a physical disk. The first 6 blocks of
all disks are assigned as 1 primary boot
block, 1 home block, and 4 secondary boot
blocks.
Directory segments, each two
blocks in length, begin in block 6, so our
logical disk must have four directory
segments (8 blocks), which accounts for
the "missing" 14 blocks.

Logical disks (also called virtual disks
and disk subsets) are simply disk files
which, through LD handler magic, take on
most of the attributes of physic31 (real)
disks.
Under RT-l1, the LD handler is an
external file (LD.SYS or LDX.SYS), and
mounted logical devices are common to all
running jobse
Under TSX-Plus, LD is implemented as an
internal system virtual overlay enabled by
setting TSGEN parameter LDSYS to 1; there
is no LD.TSX handler file. Each TSX-Plus
job (time-sharing line, virtual line, or
detached job) has its own set of 8 logical
disk units which may be mounted without
affecting other running jobs.

Why are there four directory segments?
Because DUP, when initializing a disk in
the absence of explicit instructions to
the contrary, creates a reasonable number
of directory segments based on the device
size.
If, in the example above, you
created a 5000-block logical disk file,
DUP would create 16 directory segments;
for a 100-block disk, 1 segment. If you
do not like DUP's choice, you can assign

LogiC8.1 disks have many advantages and
applic3tions. They are frequently used to
~~ivide
large disks, like RK07s, into

~e~;~=:' l:;~~"lea~~;~s ~:~:ge~nde~:~~~~~

from

directories, they permit a large device to
hold more files than the the maximum of
2322 permitted in 8. single directory.
Independent
directories also eliminate
file name conflicts.
By granting each
user (or group of users) their own logical
disk(s), you can eliminate inadvertent
deletion of other users' files, and each
user can assume responsiblity for managing
his own disk space.

to 31 segments during initializa-

Suppose you want a logical disk with 2500
blocks of file space and 10 directory
segments. You must create a file with
2526 blocks (2500 blocks of file space, 6
blocks of device overhead, and 20 director-y blocks), so use the following commands:
CREATE DM2:MYDISK.DSK/ALLOC:2526
MOUNT LDO DM2:MYDISK
INIT/NOQ LDO:/SEG:10

To create a logical disk, d~termine the
number of blocks you wish the "disk" to
have; create a file of that size on some
convenient physical disk (logical disk
files
can reside within logical disk
files, but this seldom used feature is
often more confusing than helpful); use a
MOUNT command to tell the operating system
you wish to treat this file as if it were
a disk; initialize the associated logical
disk unit.
,~.

tion by using the ISEG:nn option.

Now that you have a logical disk ready to
go, what can you do with it?
.Just about
anything you can do with a physical disk
except boot it. You can initialize it;
squeeze it; open, create, and delete files
on it; scan it for bad blocks; and assign
logical. names to it. There are two ways
to do the last, in the MOUNT command or by
using the ASSIGN command. For example,
the comHlands:

example, to create a 2000 block logi(DSK is the
default extension for LD) on DM2, use the
following commands:
r

't .1 disk called MYDISK.DSK

MOUNT LDO DM2:MYDISK
ASSIGN LDO DK

-8-

TSX-Plus User's Group Newsletter
February 1985
are equivalent to the single command

way, each user has access to SUffiCfJ,"ct
resources to perform his assigned t a \ ,
but is prevented from poking around In the
affairs of others.

MOUNT LDO DM2:MYDISK DK
If several logical names are to be assigned to a logical disk, you may assign
the first with the MOUNT command and the
others with ASSIGN commands, or you may do
them all with ASSIGN commands.

Some users have expressed interest tn
having more than 8 logical disks mounted
at any given time. This cannot be done
with LD, but some fudging with older XD,
SD, and AR disk subsetting handlers can
achieve this effect. I personally think
it is very difficult to keep track of more
than 8 simult.qneous mounts.
The only
reason anybody really wants this feature
is because it is equally difficult to keep
track of where tens or perhaps hundreds of
logical disk files are located, and to
constantly mount and remount these files.
The next column describes an IND command
file that automatically finds and mounts
logical
disk files wherever they are
located.

You can have as many logical disk files
scattered throughout your system as you
like, but you can access no more that 8 of
these at any given time, as LDO, LD1, LD3,
LD4, LD5, LD6, and LD1.
If you can't
remember which LD unit is assigned to
which file, use the SHOW SUBSET command to
display each mounted unit, the file to
which it is assigned, and the size of the
file. You can release a logical disk file
assignment using the DISMOUNT command, or
you can change the file assigned to a
given LD unit by issuing a r~placement
MOUNT command without
an
intervening
DISMOUNT for that unit.

FINDING A LOGICAL DISK FILE
As mentioned above, Horizon assigns If~·~
cal disks largely on a project basis.
We
keep two logical disks always assigned:
LDO is our electronic mailbox disk and LDl
is
our library/utility disk.
LD2 is
dynamically mounted in accordance with the
project any given user is working on and
is assigned as default device DK.
We
presently have about 50 logical disk files
stored on three emulated RK07s.
We frequently move logical disk files around to
optimize storage and disk backups, so we
generally do not know from day to day
where a given logical disk file is located.
To counter this situation, we developed, using IND and UCL, ~ simple procedure that allows T3X-Plus to find a logical disk file by project name (which
corresponds to the file name), mount it ::LS
LD2, and assign DK to LD2. We also implemented a general MNT command which functions like MOUNT, but also finds the
logical disk file for us.

Logical disks can be used .in many ways to
help organize your files more effectively.
Some sites, for example, assign each user
a logical disk file for work in progress.
Others assign logical disks on a functional basis. At Horizon, we use a combination
of approaches.
We maintain one
logical disk for each development project
or
contract, one for bookkeeping and
accounting, one for completed documentation, one for common libraries, one for
electronic mail, and one for each user as
a scratch area. Logical disks are MOUNTED
and ASSIGNED as part of each user's startup command file.
Universities
and similar organizations
with a large user body and a need to
maintain fairly high levels of data security, can assign each user a small, private
logical disk.
By mounting this logical
disk in the user's start-up command file
and by using the ACCESS command, you can
prevent that user from reading or writing
files elsewhere in the system. You may
also create another, common logical disk
containing minimally needed utilities and
compilers and assign it logical name SY in
the user start-up command file. In this

The first component of this procedure is
an IND command file called
FIND.~ "
stored on our system disk. In the 1 is •... g
of FIND.COM that follows, a couple of
command lines were too long to fit our

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TSX-Plus User's Group Newsletter
February 1985
two-column format, so we broke them at
)nvenient spots. Where a single line has
been divided, the symbol && appears.
If
you are keying this file into your system,
when you encounter this symbol, ignore it
and continue the next line, ignoring its
leading blanks, on the same line.

FIND extracts device names from a candidate list and tests each in turn to determine whether the logical disk file exists
in its directorYe If so, a MOUNT command
is executed; otherwise, the next device is
tried.
If all devices are tried without
success, or if a MOUNT command fails, FIND.
displays an appropriate error message and
terminates with a SEVERE error condition •

• ; FIND AND MOUNT A SUBDEVICE FILE
.; COPYRIGHT (C) 1984
., HORIZON DATA SYSTEMS, RICHMOND VA

To customize this file to your system,
change the quoted string in the first
command line (.SETS) to a list of all
devices you wish to search for the logical
disk file; include the terminating colon
for each device, but do not include other
characters including blanks. For example,
to search DLO, DL1, DM1, and DM2, change
the first co~mand to read:

·.;., THIS FILE MAY BE FREELY COPIED,
.; BUT NOT FOR COMMERCIAL ADVANTAGE.
·.,
., PUT DEVICE NAMES TO SEARCH (WITH
., TERMINATING COLONS BUT WITHOUT
., INTERVENING BLANKS) IN LIST

·,

.SETS LIST "DM1 :DM2:DM3:"
&ENABLE QUIET
.DISABLE PREFIX
.AGAIN:
.TEST LIST ":"
.IF <STRLEN> EQ
.GOTO NOFIND
• SETN LENG <STRLEN>
• TEST LIST.
.SETS DEV LIST[l:LENG]
.IF <STRLEN> EQ LENG .SETS LIST" "
.IF <STRLEN> NE LENG .SETS LIST &&
LIST[LENG+1:<STRLEN>J
.TESTFILE 'DEV"P2'.DSK
.IF <FILERR> NE <SUCCES> .GOTO AGAIN

.SETS LIST "DLO:DL 1 :DM1 :DM2:"
You may include any number of devices in
this list.
Devices are examined in the
order in which they appear •

MOUNT

~PI'

Next, we have def'ined two
MNT and TO, as follows:
MNT .- R IND\SY:FIND
TO .- R IND\SY:FIND LD2

UCL

commands,

MNT replaces the MOUNT command and follows
its format. For example,

'<FILSPC>' 'P3'

.IF <EXSTAT> NE <SUCCES> .GOTO NOMNT

5EXIT

MNT LD2 TSXPUG DK

.NOFIND:
j?FIND-F-File 'P2'.DSK Not Found
.EXIT <SEVERE>
• NOMNT:
;?FIND-F-Mount Command Failed - &&
MOUNT 'Pl' '<FILSPC>' 'P3'
.EXIT <SEVERE>

finds a file called TSXPUG.DSK, mounts it
as LD2, and assigns it logieal name DK •
The logical name (third parameter) may be
omitted as in the MOUNT command.
TO finds a logical disk file, mounts it 3S
LD2, and assigns it logical name DK. It
requires only the name of the logical disk
file. For example,

File processing is quite simple.
Three
parameters are passed to the file, corresponding to the three arguments of a MOUNT
command.
The first is the logical disk
device name, i.e., LDO, LD1, etc.
The
second is the name of the logical disk
file to be found, sans device name or
~xtension
(.DSK is assumed).
The last
)ptional) is the 10~ical name to be
assigned as part of the MOUNT command.

TO TSXPUG
performs the same
command above.

-10-

function

the MNT

TSX-Plus User's Group Newsletter
February 1985
the installation name or operating SY~Jf,"".m
name and version number when the at ten,"
character is typed. This is fine for "a
valid user, but it gives too much data to
an intru.der.
The long version of the
TSX-Plus message is even worse, since it
provides a partial history of the system.
The following procedure and program can
improve the security of a system with few
dial-in lines.

CHRISTMAS WISH LIST REVISITED

Many of you responded to our Christmas
Wish List for TSX-Plus features published
in the last newsletter. We thank all of
you for your input. We received a couple
of dozen letters.
Interestingly enough,
EVERYBODY
voted for Item 1, improved
system security, some with great emphasis.
We have forwarded this information to
S & H and I think we will see some improvement in this area in the near future.
Other big vote getters were Item 6 (global
logical device assignments) and Item 15
(send messages to inactive terminals).

The procedure is to run a program (as a
detached job) that monitors the modem line
until it sees a legal password.
The
program then allows the caller to log into
TSX-Plus in the normal fashion. After the
caller logs off, the program begins monitoring the line again for the password.

An unlisted item was mentioned by Ron
Tenny, namely drop case distinction in
form names for the spooler, i.e., std and
STD should be equivalent.
This change
will appear in Version 5.1C.
How's that
for service?

The program uses a CL line to monitor each
modem line.
Since a separate CL unit
number is needed for each modem line, the
number of lines that can be handled is
limited to the number of available CL
units. The program supplied monitors only
one line, but it can be extended to handle
more at the cost of increased complexi~

If you did not vote, please forward your
choices to us. We will continue to compile data and make the results available
to S & H. This is your chance to influence the design of your favorite operating
system.

The progrrun first attempts to associate a
CL unit with a TSX-Plus dial-in line. If
this attempt fails because the line is
already logged on, the program goes to
sleep for a few seconds then tries again.
If the attempt fails for any other reason,
the program gives up completely.

JOHN STEWART'S DBL/DIBOL COLUMN
Due to circumstances beyond his or our
control, John Stewart's DBL/DIBOL column
arrived too late for inclusion in this
issue. We promise his column will resume
in the next issue.

Once CL association occurs, the program
assigns
a channel and begins reading
characters from the line. At this point,
it is no longer possible for the caller to
interact directly with TSX-Plus.
Characters read are compared to the internal
password (=HI-THERE). When a match occurs, the CL assignment is released and
the user has 10 seconds to logon.

IMPROVED MODEM SECURITY FOR TSX-PLUS
Milton Campbell of Talisman Systems, who
also writes the "RT-11 Perspective" column
for Hardcopy, has submitted the following
article deaing with improved security on
TSX-Plus dial-in lines.
We have reproduced the program to which he refers at
the end of the newsletter.

The program has been tested only on DL
lines. I don't know what it will do on DZ
or DH lines, or on DL lines with programmable baud rates.
The program included
here has been simplified to reduce its
size, but there are several additions t~~.::~
should be considered. It should not"l
too much trouble to add support for add{tional lines, although the cost In CL

The access security provided by TSX-PLUS
is adequate for many installations; however, additional security for
dial-in
lines may be desirable.
Many systems,
including TSX-Plus, display such things as
-11-

TSX-Plus User's Group Newsletter
February 1985
units

a problem. The program should
lock itself into memory while
reading characters from the CL line.
~robably

Calling a modem controlled by this program
is a little mysterious because there is no
indication that the computer has responded
to the call until the internal p~ssword is
entered.
This is intentional, but some
kind of innocuous prompt could be added to
give legitimate callers a warm feeling.
The program could also be extended to add
other user interactions such as a callback feature. After validating the internal password, the program could request a
location identifier, then hang up the line
and call the originating terminal back.
This method is not a complete solution to
security problems, even for one modem
line.
Among other things, there is a
window after a user logs off but before
the program recycles during which another
caller bypasses the program.
Beyond the
cost tn CL units, this program consumes a
detached line and imposes some overhead
~ile
reading the password and while
waiting for the user to log off.
CURRENT VERSIONS
The

current distributed version of TSXis 5.1B, generally identical to the
Version 5.1 some of you may ha~e. Version
5.le, scheduled for release in March, is
in field test.
Version 5.1C adds a few
new features 9 but largely corrects several
errors in 5.1B.
PlUS

.TITLE

WA.TCH

Some 5.1B errors corrected in 5.1C involve
field-width terminal input
activation,
stack overflows caused by the parallel
printer (LP) handler, case discrimination
on spooler form names, extended channel
(above 16 decimal) purging, low memory
fragmentation, and multiple simultaneous
CL usage (see HINTS AND KINKS column). As
usual, the technical support group at
S & H, headed by Jan Bramlet, has been
very responsive to user problem reports in
creating this new release. If you don't
think we a~e lucky in this regard, talk to
a few RSTS users.
READER CONTRIBUTIONS
We r~epeat our oft-stated request that
readers contribute to this effort.
You
needn't write a lengthy article, but there
are se~eral things you can do to help us
help you. We would like to publish brief
(four paragraph or so) reviews of software
packages you have purchased and installed.
Tell us what the package is, what you
wanted to do with it, what you ended up
doing with it, and your general reactions
to its quality, documentation, etc. If
you have developed a few clever command
files or UCL co~~ands that make using
TSX-Plus easier, share them with us.
If
there is something about TSX-Plus that you
just don't understand, let us know; it may
be a topic for a tutorial.
We will return in three months. The next
issue should reach you right after the New
Orleans DECUS. Goodbye until then!

TSX+ MODEM SECURITY PROGRAM

BASIC MODEM SECURITY PROGRAM
BY:
MILTON D. CAMPBELL
TALISMAN SYSTEMS
SET THE FOLLOWING TO THE "RE-CAPTURE" CYCLE INTERVAL, IN TICKS
RECYCL=120.

;120. = 2 SECOND INTERVALS
;

; SET THE FOLLOWING TO THE TSX LINE NUMBER THAT IS THE MODEM
-12-

TSX-Plus User's Group Newsletter
February 1985

MODLIN=2
;

; SET THE FOLLOWING TO THE CL: LINE NUMBER TO BE USED
CLLINE=l
;

.MCALL

.TWAIT,.PRINT,.SPFUN,.EXIT,.LOOKUP,.PURGE

ERRBYT=52
START: :
.JMP

TRY

WE COME HERE WHEN AN ATTEMPT TO CAPTURE THE TSX LINE
;
FAILS. GO TO SLEEP FOR A WHILE, THEN TRY AGAIN
RETRY:
.TWAIT IITWBLCK ,IITIME
BCS
RETRY
;FAILED? TRY AGAIN
TRY:
MOV
IICAPTUR,RO
;POINT RO TO THE EMT BLOCK
EMT
;TRY TO GET THE LINE
315
BCC
SUCCES
;TO BEGIN THE P/W SEQUENCE
CMPB
115,ERRBYT
;CODE 5 IS "LOGGED ON"
BEQ
RETRY
;IF SO, LOOP AGAIN
JMP
FATAL
;ANYTHING ELSE IS FATAL
SUCCES: :
MOV
Ir'RCLO, CLBLCK
ADD
IICLLINE,CLBLCK
• LOOKUP HLKBLCK,#O,#CLBLCK
BADPW:
MOV
IIPSSWRD,R4
;POINT R4 AT PASSWORD STRING
CLR
STATE
;HAVE NOT STARTED PASSWORD
CLR
SIZE
COLLCT:
.SPFUN IISPBLCK,1I0,1I203,HINCHAR,1I1,HO
TST
STATE
BNE
30$
;BR IF INSIDE PASSWORD
CMPB
(R4),INCHAR
;SEE IF STARTS PASSWORD
BNE
COLLCT
INC
STATE
;SHOW COLLECTING PASSWORD
30$:
CMPB
(R4),INCHAR
;SEE IF CHARACTER MATCHES
BNE
BADPW
;IF NOT
INC
R4
;POINT TO NEXT CHAR
INC
SIZE
CMP
SIZE,flPWLEN
;SEE IF' SIZE OK
BLT
COLLCT
;IF NOT AT END
• PURGE #0
MOV
IIFREE,RO
;POINT RO AT DISCONNECT BLOCK
EMT
;DISCONNECT DL
315
.TWAIT fITWBLCK, ~/LNTIME ;GIVE USER TIME TO LOGON
JMP
TRY
FATAL:
-13-

TSX-Plus User's Group Newsletter
February 1985
MOV
EMT
.EXIT
STATE:
SIZE:

.WORD
.WORD

tlEBLCK,RO
375

;POINT TO MESSAGE BLOCK

0
;

; THE PASSWORD IS DEFINED IN THE FOLLOWING
PSSWRD: :
.ASCII
PWLEN=.-PSSWRD

I=HI-THEREI

INCHAR: .BYTE

;COMPUTE LENGTH

.EVEN
; EMT BLOCKS
SPBLCK: .BLKW
.BLKW
EBLCK:
.BYTE
.WORD
.WORD
TWBLCK: .BLKW

6
II

'-t

0, 127
1

FMESSG
2

;

CAPTUR: .BYTE
.WORD
.WORD

0,155
CLLINE
HODLIN

;"CAPTURE" EMT BLOCK

FREE:

0,155
CLLINE

;"FREE" EMT BLOCK

;

.BYTE
.WORD
.. WORD

CLBLCK: .RAD50
.RAD50
TIME:

w" . . . .

• vnu

LNTIME: .WORD

o
ICLOI
IWRKFILXXXI

;FILE NAME (NOT USED)

O,RECYCLE

;RE-CAPTURE CYCLE TIME

0,600.

;USER HAS 10 SECONDS

;

FMESSG:
.ASCII
.ASCIZ
.END

I? WATCH-Fatal Error:1
I Unable to Associate CL: linel
START

-14-