DRLOGOIW.WS4 (= Dr. Logo articles in "InfoWorld" magazine)
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- "Digital Research announces DR Logo for IBM PC"
Scott Mace
"InfoWorld", 14 February 1983, Vol.5, No.7, p.10
(Retyped by Emmanuel ROCHE.)
Digital Research is entering the educational software market with a version of
the Logo language for the IBM Personal Computer.
Versions of Digital Research's DR Logo will also be made available for other
machines that run CP/M, according to Gary Kildall, president of Digital
Research.
The announcement represents the first major breakthrough in attempts to turn
CP/M business computers into tools for education. Previously, Logo was
available only on home computers -- in several versions for the Apple II, as
well as versions for the radio Shack color Computer and TI-99/4A.
Logo is suddenly spreading to other computers, though. In January (1983),
Mattel announced a Logo cartridge for its new Aquarius home computer, and
Atari has announced that Logo Computer Systems, Inc. (LCSI) is implementing
Logo for Atari's computers.
Now Digital research, which developed the CP/M operating system and sold
software primarily to programmers and businesses, is showing signs of jumping
into the home-computer software arena.
"We recognize a tremendous opportunity for Digital Research in the low-end
computer market, and Logo is the first product to demonstrate our commitment
to serving the needs of this new consumer market", Kildall said.
DR Logo will be available for the IBM PC during the third quarter of 1983.
Price is not set, but Kildall estimated it would fall in the $100 to $200
range. A color-graphics adapter card for the PC will be required.
Kildall said DR Logo includes all features of Apple Logo, the Logo
implementation that grew out of the work done by LCSI. DR Logo offers
increased memory capacity, however, and various utilities for programmers. "We
have added quite a bit to it, to make it a little more professional and easier
to use", Kildall noted.
The DR Logo is aimed not only at children, but at business users as well.
Kildall noted that Logo, which was developed by MIT professor Seymour Papert,
grew out of the LISP (LISt Processing) language, from which much artificial-
intelligence research has evolved.
Kildall believes business users can utilize Logo's powerful list-processing
capabilities, as well as the more publicized turtle-graphics commands.
One adjustment Logo will have to make for the business world will be
terminology. "You turn that *turtle* into a *pointer*, because businessmen
don't work with turtles", Kildall said. "In effect, the turtle becomes a
positioning device, rather than an Etch-A-Sketch."
In a speech given before hundreds of CP/M'83 (show) attendees, Kildall
contended that Logo has various shortcomings that prevent it from becoming,
for example, a replacement for COBOL. "It does open up a lot of new areas", he
said. "We are not going to accept anything less than Logo, as far as the next
generation of languages for home computing." In fact, Kildall implied that
future versions of DR Logo could replace BASIC.
Kildall said the BASIC language "turns out to be a very poor approach to
teaching someone how to use computers. In many cases, it is very limiting to a
child."
"The introduction of DR Logo is the first in a series of products we are
developing to make computers more accessible to people", Kildall said.
Logo aficionados will note a number of added features in DR logo not found in
the Apple, TI, or Radio Shack Logos. Among these are:
- Larger work space
Blocks of logo work space typically are measured in nodes, and Kildall
said that the IBM PC version of DR Logo, which has one megabyte of
memory space, offers 100,000 nodes, as opposed to 2,500 for the Apple
II. "The kinds of problems you can solve can be much more
comprehensive", he said.
- Built-in help commands
These explain the Logo primitives (built-in commands) and provide
examples of how they can be used. A full-screen procedure editor
explains editing commands.
- Comments with programs
These comments explain individual operations and statements.
- Text windowing
Commands and editing can appear within a window on the user's screen,
to the text does not interfere with graphics. The location of the
window is defined by the user. The version displayed at CP/M'83 also
allowed users simultaneously to use a monochrome monitor to display
text and a color monitor to display graphics. Kildall said a toggle
switch will also let color-monitor users switch from graphic to list
displays.
- Indentation of procedure statements
According to Kildall, even though other Logo packages show indented
procedures in user manuals, many of these packages cannot accept
indenting on the screen.
- Debugging aids
With these, the program can show the user what each program line is
doing. Users can change variables and values at this point to observe
theirs effects, then continue with the program execution. Another tool
decodes procedures into their component instructions.
- Upward compatibility with Digital Research's GSX (Graphics System
Extension), a graphics protocol consistent with the emerging ANSI
Virtual Device Interface (VDI) standard.
Kildall was introduced to Logo through John Allen of The Lisp Company (TLC) of
Los Gatos, California, which is developing a plug-in Logo cartridge for the
Mattel Aquarius, a Z-80 home computer ("InfoWorld", Vol.5, N.5). The Lisp
Company was displaying its own Logo at CP/M'83. Allen was involved with
pioneering artificial-intelligence work done at Stanford University.
Allen said the Aquarius Logo fits in 16K of ROM. The prototype displayed at
CP/M'83 had 6 moving turtles on the screen, and Allen said the system can
accept as many turtles as space allows.
A graphic example of the power of multiple turtles are the "toiling turtles"
and "tiling turtles", to be included with the mattel Logo. Toiling turtles are
synonymous with normal Logo turtles, and tiling turtles can take on one of 256
possible shapes in an 8-pixel X 8-pixel block of color. These tiling turtles
can create stunning animated graphics.
Digital Research will license Logo from Allen's firm to develop other versions
of Logo for Z-80 and 8086 computers. Unlike DR Logo, which was written in C,
these other versions will be written in LISP, another language The Lisp
Company is providing on its own. Allen expects the new versions to be ready in
90 days.
Allen said these versions of Logo will be suitable as general-purpose
programming tools, unlike typical Logo implementations. "These will be small
LISPs, in a sense", he said.
Allen also foresaw a Logo so powerful that turtles could simultaneously
perform multiple tasks, such as initiating message-passing.
- "Review: DR Logo"
Mark Renne
"InfoWorld", 13 February 1984, Vol.6, No.7, p.45
(Retyped by Emmanuel ROCHE.)
DR Logo is Digital Research's contribution to the fast-growing world of the
Logo language. Originally designed to teach young children how to program
computers, this easy-to-learn language is becoming popular for many different
applications.
DR Logo is designed specifically for the IBM Personal Computer, and takes
advantage of the PC's 16-bit processor and function keys.
Logo strives for simplicity in all operations. The language is best known as
the first to use so-called turtle graphics, a technique that uses a cursor in
the shape of a turtle to draw on the screen. You can move the turtle in any
direction for any distance. The trail it leaves creates pictures, such as
circles, squares, and other shapes. Simple English commands, such as forward,
right, and left, direct the turtle's activities.
Logo is composed of nearly 200 built-in commands, called primitives. You
combine primitives as building blocks for your own commands, procedures, and
programs. (For those of you who know a bit of programming, Logo commands are
like subroutines in BASIC, or procedures in Pascal.)
Logo's potential is boundless. The ease of programming and of creating simple
turtle graphics tempts both beginning and advanced programmers. Logo offers
features unknown in business languages, and provides speed and flexibility for
educational programming. Logo may become the language of choice for teaching
programming.
DR Logo presents a shining performance. Its turtle graphics are fast and
flawless. With simple commands, you can define both background and trail
colors to present dramatic graphics. DR Logo's full-screen editor, for
developing your commands, procedures, and programs, makes programming a
pleasure. Since Logo is a very simplistic language, detecting and correcting
your errors is easy.
DR Logo requires no installation for either hardware or software. People with
no computer experience can use it. Complete instructions help those using
their computer for the first time. Clear illustrations show how to put the
diskette in the drive, and line-by-line programming examples guide the novice.
DR Logo's Help function allows you to check the syntax and function of any
primitive and, once you have written your procedure or program, the debugging
utilities make it easy to correct mistakes. The Debug command divides the
screen into 2 sections. One section shows each command as it is executed; the
second shows the program's output.
There are options to allow procedures to execute either with or without user
intervention. You may also examine expression results as the program runs. We
found these functions most useful in debugging our newly-created DR Logo
functions.
DR Logo divides the computer's available memory into a workspace, which is
divided into nodes of 5 bytes. You may have over 10,000 nodes. This is
substantially greater than most implementations of Logo. There are also
procedures for saving memory, and "garbage collection" to free up used memory.
DR Logo fully supports mathematical and trigonometric functions. It includes
transcendental functions, logarithms and inverses. DR Logo recognizes real
numbers to 15 significant digits. Integers may range from -214783647 to
+214783647. DR Logo also supports symbols for positive and negative infinity.
Whereas BASIC will respond to 1/0 as an error, DR Logo will respond with +INF
for positive infinity. (You did know you could divide by zero, didn't you?)
Since you will want to save your newly-created procedures, DR Logo provides
commands to prepare either single- or double-density diskettes for use, which
allows you to permanently store your programs on disk. Such program storage is
quick and painless.
None of the standard Logo primitives are missing. Since Logo is a fairly new
language, the different versions are often compatible, and we typed in several
programs from a national Logo users' group without change.
The printed documentation for DR Logo is superior. It includes a simple
tutorial manual, a reference manual, and a command-summary booklet to keep
near the computer for quick reference. Both manuals contain numerous full-
color illustrations. Each has an index, a complete glossary, and appendices.
The sample programming exercises included in the tutorial also illustrate
possible errors and solutions. The reference section contains syntax and other
information for each primitive, with simple programs that demonstrate proper
usage.
Since DR Logo purchasers will need more information if they want to do
advanced programming, Digital Research has included references to books,
magazines, and Logo users' groups.
Unfortunately, the program comes on copy-protected media. Digital Research
supplies a master disk and one backup. Registered owners can replace damaged
system disks at a cost of $25 each. Since this program is made to be used by
children, our enthusiasm for the product was slightly dampened. Although
programs are saved to other disks, and the system disk can be removed at the
beginning of a DR Logo session, there is still a good chance of damage,
especially at the primary- or secondary-school level.
On the plus side, Digital Research has a fine reputation and excellent
customer-support system. The purchase price includes a subscription to its
newly-created DR Logo Newsletter.
DR Logo is a fine version of Logo for the IBM Personal Computer. It provides
many functions not found in other languages, and allows easy creation of
graphics using a clever turtle. The program is easy to use and learn. The
documentation is above average, and we hope other companies follow Digital
Research's style. Our only reservation with the program is that it is copy-
protected. If you are interested in Logo, perhaps a visit to the doctor is in
order.
- "On DR Logo"
"InfoWorld", 16 April 1984, Vol.6, No.16, p.49
(Retyped by Emmanuel ROCHE.)
Although I enjoyed your review of DR Logo (February 13, 1984), I think you
could have been tougher. DR Logo is, indeed, an excellent performer, but it
has some real shortcomings on some machines. DR Logo's requirement of 192K RAM
[random-access memory] rules it out for the IBM PCjr, the home/classroom
computer it should run on. IBM PC XT owners will find it impossible to store
files from either the copy-protected DR Logo system disk -- or even their own
programs -- on the PC XT's hard disk, which cannot support DR Logo's CP/M-86
operating-system environment.
Although the review states that none of the Logo primitives are missing, DR
Logo does omit the Setscrunch command. This command controls the vertical to
horizontal ratio of the monitor, which is critical for the graphics-rich Logo
program since it corrects the proportions and resolution of the display. All
the other IBM logos have it.
Your review also compliments DR Logo's large work space. I found its 9,556
nodes smaller than PC Logo's (10,225 nodes) or even IBM's own Logo software
offering (31,093 nodes).
As for documentation, I agree that DR Logo's is the longest and most detailed
of the manuals. But it is poorly organized. A 280-page, single-spaced, photo-
offset reference manual with a 4-page index does not merit the excellent
rating found in the review. It is a poor second to the clearly written, well-
organized text found in PC Logo or the IBM manual. Had the "InfoWorld" review
compared DR Logo with other Logo programs for the IBM PC, these shortcomings
would have been more evident.
Laurence L. Greenhill, M.D.
I found your review of DR Logo to be interesting, but a bit swallow. Having
used the package for some time, I found your ratings to be overly generous.
For example, performance was rated as excellent. Unfortunately, DR logo is
slower than some implementations of LISP and Logo on the IBM PC for many
operations, including graphics and list manipulation. Even BASIC is faster at
string manipulations than DR Logo.
The documentation is good and deserves an excellent rating, although a
reference card would be nice. However, the reference in the review to the on-
line help option is somewhat misleading. This function simply prints out a
very large text file that contains a short description of each function. Using
the manual is faster and easier.
Your review also did not describe some of the more significant shortcomings of
the implementation. For example, file-system support is minimal, at best, and
the copy protection has an additional implication. As it turns out, DR Logo
runs under CP/M-86, but can only be run from the system disk supplied with DR
Logo. There is no way to exit to the CP/M-86 operating system. This means that
the package will not run with existing CP/M-86 or Concurrent CP/M systems.
William G. Wong
Our performance grades for software are based not only on speed, but also on
what features are included with the product, and how well they are
implemented. -- Editors.
- "Learning Logo"
"InfoWorld", 30 July 1984, Vol.6, No.31, p.37
(Retyped by Emmanuel ROCHE.)
In August (1984), Digital Research Inc. will introduce a series of three
software programs to help first-time users learn the DR Logo Language.
Simultaneously, the company will make available a version of DR Logo that
requires only 128K random-access memory (RAM) to run, instead of the currently
required 192K RAM.
"DR Logo Graphics", "DR Logo Games", and "DR Logo Words" are designed as an
inexpensive way, for those with no prior computer experience, to use DR Logo,
says Fred Cutler, senior marketing director of the Consumer Products Division
for the Pacific Grove, California, company.
The $39.95 "learning pacs" will run on the IBM PC and PCjr. Starting in
October (1984), the programs will be available in versions compatible with the
Apple II series. Commodore 64 versions will be available by the end of the
year. The new version of DR Logo will sell for $99; the current product sells
for $149.
Each learning pac comes with about 30 cards in a plastic case; they are
intended to replace documentation, Cutler says. Information is listed on the
front of the card, and an application using the information is on the back,
for a step-by-step guide to using DR Logo. The library of cards is geared for
first-time users of any age, he says.
EOF