tcj_27 1986-11.pdf

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Programming
User Support
Appl ications
Issue,27
$3.00
68000 TinyGiant
Low Cost 16-bit SBC and Operating System
The Art of Source Code Generation
Disassembling Z-80 Software
Feedback Control System Analysis
Using Root Locus Analysis and Feedback Loop Compensation
The Hitachi HD64180
New Life for 8-bit Systems
A Tutor Program for Forth
Writing a Forth Tutor in Forth
Disk Parameters
Modifying The CP/M Disk Parameter Block
for Foreign Disk Formats
ISSN
I 010-9331
THE COMPUTER JOURNAL
190 Sullivan Crossroadl
Columbia Falls, Montana
59912
406-257-9119
Editor/Publisher
Art Carlson
Art Director
Donna Carlson
Production Assistant
JudIe Overbeek
Circulation
Donna Carlson
Contributing Editors
C.
Thomas Hilton
Donald Howes
Jerry Houston
Bill Kibler
Rick Lehrbaum
Peter Ruber
Jay Sage
Jon Schneider
The
Features
COMPUTER
JOURNAL
".
68000 TinyGiant
Hawthorne's 68000 Single Board
Computer combined with their $50
operating system
by Art Carlson
4
The Art of Source Code Generation
Disassembling Z·80 software to
produce modifiable source code
by Clark
A.
Calkins
8
Feedback Control System Analysis
Using Root Locus analysis and Feedback
Loop Compensation to solve closed
loop control problems
by Bert P. van den Berg
14
The Hitachi HD64180
Entire contents copyright©
1987 by The Computer Journal.
Subscript/on
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Send subscrIptions, renewals, or
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ColumbIa Falls, Montana,
59912,
or
The Computer Journal, PO Box
1697, Kalispell, MT59903.
Bulletin Board-Our bulletIn board
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Address all edItorial and adver-
tising inquIries to: The Computer
Journal, 190 SUllivan Crossroad,
ColumbIa Falls, MT
59912
phone
(406)
257·9119.
'
Understanding the HD64180's advantages
over the Z'80, and how to use some of it's
advanced features
by Jon SchneIder
23
A Tutor Program for Forth
Writing
a
Forth Tutor in Forth
by Bill Kibler
36
Disk Parameters
Modifying the CP/M Disk Parameter Block
to read and write foreign disk formats
by
C.
Thomas Hilton
40
Departments
Editorial
C Corner
by Donald Howes
2
18
~
ZSIG Corner
by Jay Sage
28
34
52
1
Reader's Feedback
Computer Corner
by Bill Kibler
The Computer Journal/Issue
1127
,Editor's Page
buying computers. When a government
agency buys a computer, the taxpayer
pays the bill. When a corporation buys a
computer, the company's stockholders
pay for it. Individuals, however, have no
choice but to spend their own money. So
the price of the machine, as well as its
features (clock rate, ease of use, bundled
software, etc.) become deciding factors
in a sale." George goes on to say, "Thus,
the key to next year seems to be in the
hands of individuals, just as it was in
1986. Will they continue to buy at the pace
they established in 19867"
Digesting what George said, I feel that
when corporations and government
agencies became the primary buyers,
most sellers structured their product
line, marketing organization, and pricing
for this 'big-business' segment. Now that
individuals and small companies are
again the primary buyers, these sellers
have too much built-in overhead cost and
are burdened with products and
marketing plans designed for those
spending someone else's money. The
ones succeeding in the current market
are the lean and hungry ones who can
provide the features and prices deman-
ded by the individuals spending their own
money.
At the same time as the current
productS are being sold in volume, there
are
also
a lot of technical developments
taking place which will affect what we
buy in the near future - but these
developments are not taking place in the
consumer market which everyone is
watching, but rather in the industrial
market where they are not attracting
much attention.
There
is
a lot of talk about how much
power the Motorola 68020, 68030, and
68040 and the Intel 80286, and 80386 will
provide, but there is very little talk about
what kind of system architecture
will
be
needed in order to realize these benefits.
It's true that MicroSoft and others are
developing operating systems for the
80386, but apparently the hardware
people (remember that they are used to
dealing with buyers spending some one
else's money) are talking about putting it
on a glorified PC-type bus. That's like
putting a turbo-charged V-12 engine in a
old Ford model T.
I feel that the advanced business,
engineering, and industrial systems
which can properly utilize the power of
the new CPU's will be multiuser,
systems
employing
multitasking
mutiprocessors and
will
require a
Market Developments
While some people claim that the per-
sonal computer sales are flat because the
sales of their own products are low, and
others claim that the technology is
stagnate because all they see is the IBM
PC series, there is actually a great deal
of activity in both sales of existing
products and technical developments
which will lead to the next generation of
computers.
If
anyone tells you that computers
aren't selling, show them the current
issue of Computer Shopper which has 408
pages mostly filled with ads for har-
dware and software. Many of these ad-
vertisers have been running full page or
even multipage ads in every issue, and
those I talk to assure me that the ads are
generating the sales to justify the cost of
the ads - they're selling a lot of har-
dware, software, and peripherals - but
the market has made another abrupt
change. As pointed out in George
Morrow's
column
in
Electronic
Engineering Times (January 12, 1987,
page 61), individuals started buying
again in 1986 while the corporations and
government agencies cut way back on
their purchases. To quote one small sec-
tion of his column, "The personal com-
puter market was launched by in-
dividuals who were convinced that the
power of low-cost micros could be har-
nessed to solve spreadsheet applications
and word processing chores, and it's no
secret that this type of customer doesn't
use the same criteria as corporations or
government agencies when it comes to
2
Ever Wondered What Makes CP/M®
nck1
Source Code Generators
by C. C. Software
can
give you the answer.
"The darndest thing
I ever did see ... "
" ... if
you're
at
all interested
in
what's going on in
your system,
it's
worth it."
Jerry Pournelle,
BYTE, Sept '83
The S.C.G. programs produce
fully commented and labeled
source code for
your
CP/M
system
(the
CCP and
BOOS
areas).
To modify the system to
your
liking,
just edit and assemble with ASM.
CP/M 2.2 $45,
CP/M+ $75, + $1.50 postage (in Calif add 6.5').
C. C. Software, 1907 Alvarado Ave.
Walnut Creek, CA 94596 (4l5}939-8l53
CP/M is a registered trade.ark of Digital Research, Inc.
The Computer Journal/Issue
1127
reliable bus structure which provides for
interprocessor communications and
multiprocessor communications. I'm
sure that many readers will comment on
my negative stand on the current
multitasking and multiuser implemen-
tations - and that's because I feel that
the currrent systems do not have suf-
ficient power to properly execute these
feature.
If
we don't need these features,
then we don't need the new chips either!
I'm happy with my s-bit systems with
hard
disks for wordprocessing which
is
the majority of my work. I'll probably
upgrade
to
solid state
RAM
to
speed
things
up a little and avoid the
disk
noise,
but I surely don't need a 16-bit or 32-bit
CPU and I don't need multiuser or
multitasking for our operation (although
other larger operations may well need
this>.
Eight bit systems are cheap, and if
I want
to
do several things at the same
time, I just use several systems at the
same time!
I am very interested in the new chips
for other applications, but when I choose
a powerful chip because of its features
I
insist on being able
to
use ALL of its
speed and power!
If
limited power
is
ac-
ceptable, I can provide that with existing
CP/M or PC-DOS equipment.
If
more
power
is
needed, then I want to be able to
use everyting that I can get.
The industrial market has already
developed architectures such as the
VMEb~
(Motorola) and Multibus lI
i1l
(InteD which provide most of the
features required to use the full power of
the new CPUs, and 68020, 80286, 80386,
and WE32XXX single board computers
are readily available. Simple low power
systems can be used with a simple
lo~
power bus - or even without a bus - but
high-power systems must be
used
with a
high-power bus in order to realize their
full potentials and to provide for expan-
sion. I'll only be interested in using the
new CPUs on a standard open bus, ex-
cept possibly for a dedicated single use
application such as a CAD station.
While we're talking about the new
CPU's,
it
appears that the software
developers have stopped their work on
the AT 80286 in favor of the 80386. Without
the software
to
make use of the '286's
features, the AT
will
just be used as a
fast PC instead of realizing its full poten-
tial.
color ads, but then when we try
to
get
technical information they fall flat on
their face.
An
example is the AD639 Trig
Processor chip from Analog Devices. I
wrote
three
letters asking for tech info to
publish, but never received a response.
In November I finally phoned and talked
to someone in marketing who promised
to
send the info. We still haven't received
anything, and frankly I'm no longer in-
terested in dealing with them.
On the other hand, I called Hitachi for
info on their HD64180 and received a
large
box
of material. They also followed
up with a phone
call
to
see
if I had
received it and if I needed any further
help.
Guess
which product I'll support. The
American companies
will
continue
to
cry
about how they are losing business
to
the
foreign producers, but in many cases
it
is
their own fault because while they spend
money on impressive advertising they
won't pay attention to customers and
provide support.
M
o
V
I
N
G
?
•
Make certain that TCJ follows you
to
your new address. Send both old and
new address along with your
expiration number that appears on
your mailing label
to:
THE COMPUTER JOURNAL
190
Sullivan Crossroad
Columbia Falls,
MT
59912
Hard
Drives vs. RAM Disks
Hard drives are nice for operations in-
volving a lot of disk access such as data
bases or compiling where the speed and
capacity advantages over floppies are
important - BUT remember that when
used continuously, every hard drive
will
eventually FAIL! The question is not IF,
but rather WHEN. The expensive large
drives intended for mainframe ap-
plications
will
probably last for a long
time, but some of the low cost drives for
micros are not so durable. In the case of
the 10 Meg drive for our BBS the
bearings gave out after about six months
of continuous operation. I noticed it in
time to save the data, but I'll have to
send the drive out for repair.
The board
is
running on just two flop-
pies until I decide on a long term
solution, but I question if I want a hard
drive running 24 hours a day for seven
days a week. I may add more 96TPI flop-
pies because the drives only run when
they are accessed instead running all the .
time like a hard drive. The real solution
will
be to go to battery backed
RAM
disk
if and when I can justify the cost. I would
be very interested in feedback regarding
other people's experience with the life of
various models of hard drives.
Source Code
I realize that you get tired of hearing
me talk about source code, but having
the source code is what enables us to
(Continued on page 38)
Please allow six weeks notice. Thanks.
Registered Trademarks
It is easy
to
get in the habit of using
company trademarks as generic terms,
but these registered trademarks are
the property of the respective com-
panies. It is important to acknowledge
these trademarks as their property to
avoid their losing the rights and the
term becoming public property. The
following frequently used marks are
acknowledged, and we apologize for
any we have overlooked.
Apple II, 11+ • lIe, lIe. Macintosch,
DOS 3.3, ProDOS; Apple Computer
Company. CP/M, DDT, ASM, STAT,
PIP; Digital Research. MBASIC;
Microsoft. Wordstar; MicroPro Inter-
national Corp. IBM-PC, XT. and AT;
IBM Corporation. Z-80, Zilog. MT·
BASIC, Softaid, Inc. Turbo Pascal,
Borland International.
Where these terms (and others) are
used in The Computer Journal they are
acknowledged to be the property of the
respective companies even if not
specifically mentioned in each oecuren-
Why
Companies Don't Succeed
Most companies want to have their
products considered for new designs, and
they spend a lot of money for slick four
The Computer Journal/Issue
1127
ceo
3

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