[editor : Christopher Morgan] [publisher : Virginia Londoner, Gordon R Williamson, John E Hayes] #Magazine

#Abstract

This month's cover painting by Robert Tinney shows our own solution to the energy crunch: a computerized "solar system." To illustrate this month's theme of energy conservation, we present a variety of articles, including "Harvesting the Sun's Energy," "Computer Simulation of a Solar Energy System," "Energy Conservation With a Microcomputer," and "Energy Measurement With the Apple."

Also in this issue are a discussion of IBM's new personal computer; the first part of Steve Ciarcia's exciting new Z8 single-board computer project (about which there was much interest at the recent National Computer Conference); another solution to the traveling-salesman problem; Micromodem support in Apple Pascal; Kalman filters; hurricane tracking by computer; the Atari Assembler/Editor; a report on the Santa Cruz Computer Othello tournament; and much more, including all the regular BYTE features.

[author : Chris Morgan] #Edito

Extract : «  The year 1981 will be important in the history of personal computing for two reasons: the "invasion" of Japanese personal computers, and the entry of major computer companies such as IBM into the market. Rumors abound about personal computers to come from giants such as Digital Equipment Corporation and the General Electric Company.

But there is no contest.

IBM's new personal computer (most likely to be officially announced this month) is far and away the media star, not because of its features, but because it exists at all. When the number eight company on the Fortune 500 list enters our field, that is news. And when you take a close look at the computer's design, that is news, too. Although the complete description of the computer is still subject to conjecture, sources close to IBM have given me an intriguing glimpse of the machine. [...]  »

TABLE OF CONTENTS

One of the surprises was the impressive showing of the microcomputers and hand-held electronic units.

[author : Peter W Frey] #Event #GameBoard #Book

Extract : «  In mid January, when the Midwest and Northeast were weathering heavy snows and subzero temperatures, programmers from the US and abroad, laden with microcomputers or terminals and modems, traveled to the University of California in sunny Santa Cruz, for the Santa Cruz Open Othello Tournament. Each programming team had been preparing for months for decisive head-to-head competition in which only one program would triumph as champion. For individuals accustomed to solitary, cerebral pursuits, this tournament provided a public arena in which to demonstrate their skills.

The focus of this concentrated preparation was a complex strategy game, originally called Annexation, then renamed Reversi. It is now known as Othello, a trade name of CBS Inc. The rules of play and strategic ideas for this game have been discussed in earlier issues of BYTE (see references at the end of this article). [...]  »

Zilog's new single-chip microcomputers ease the construction of a small, inexpensive computer system.

[author : Steve Ciarcia] #Electronic #ComputerKit

Extract : «  The time has come to present a versatile "Circuit Cellar Controller" board for some of these more ambitious control projects. I decided not to adapt an existing single-board computer, which would be larger, more expensive, and generally limited to machine-language programming. Instead, I started from scratch and built exactly what I wanted.

The microcomputer/controller I developed is called the Z8-BASIC Microcomputer. Its design and application will be presented in a twopart article beginning this month. In my opinion, it is a milestone in lowcost microcomputer capability. It can be utilized as an inexpensive tinyBASIC computer for a variety of changing applications, or it can be dedicated to specialized tasks, such as security control, energy management, solar-heating-system monitoring, or intelligent-peripheral control. [Editor's Note: We are using the term "tiny BASIC" generically to denote a small, limited BASIC interpreter. The term has been used to refer to some specific commercially available products based on the Tiny BASIC concept promulgated by the People's Computer Company in 1975... RSS]

The entire computer is slightly larger than a 3 by 5 file card, yet it includes a tiny-BASIC interpreter, 4 K bytes of program memory, one RS232C serial port and two parallel I/O ports, plus a variety of other features. (A condensed functional specification is shown in the "At a Glance" text box.) Using a Zilog Z8 microcomputer integrated circuit and Z6132 4 K by 8-bit read/write memory device, the Z8-BASIC Microcomputer circuit board is completely self-contained and optimized for use as a dedicated controller. [...]  »

A computer model helps determine the amount of solar energy received by a flatplate collector.

[author : George E Mobus] #Listing #BASIC #Energy

Extract : «  As the cost of fuel continues to skyrocket, more people are looking toward the sun to meet their energy needs. The potential use of solar energy for both heating and electric power generation is tremendous. By some estimates, energy from the sun could account for more than onethird of the nation's total energy needs by the year 2000. There are even more optimistic estimates that are based on technological "breakthroughs" such as the much publicized solar space station. If solar energy can be "harvested" in outer space by a station in geosynchronous orbit, it can be beamed down to the earth's surface as low-power microwaves. In such a scenario, as much as 80% of our energy may come from the sun.

No doubt such highly developed systems for exploiting this vast, nondepletable energy source will come into play as the economics of energy production make solar-conversion technology more competitive with conventional, nonrenewable forms of fuel such as oil, gas, and coal. [...]  »

This sunrise-sunset program calculates many parameters associated with the sun, including the amount of solar radiation received by the earth.

[author : Bruce Barkstrom] #Listing #BASIC #Mathematics #Astronomy #Book

Extract : «  Do you have to rise before the crack of dawn to go duck hunting? Do you need to know how many hours of sunlight to expect for your new solar collector? Do you want to know if you have enough time to jog ten miles before the sun sets? One way to answer these questions is to use your computer. All you need to know is your latitude, longitude, and the date. The program shown in listing 1 computes the time the sun rises or sets for any date and location on the earth. It uses a precise calculation of the sun's position in its apparent orbit around the earth and relates this to the time of sunrise and sunset by geometry.

The sun's orbital position is found with a general method that might be of use in your next space-war simulation. A general Julian-date calendar is also included, which might be useful in keeping track of days in an accounting program. The times of sunrise and sunset are computed with a method that also gives the amount of solar energy falling on the surface of the atmosphere for a given latitude and date. [The amount of solar energy reaching the surface of the atmosphere is considerably different from the solar energy actually reaching the surface of the earth. Although the amount of energy actually radiating through the atmosphere can be calculated, it requires more complex mathematics than those used in this article. The solution involves solving a partial differential equation known as the equation of radiative transfer... SM] For the twentieth century, the times computed are accurate to within two minutes.

The fact that the sun rises at different times during the year is not mysterious. It is caused by the tilt of the earth's axis with respect to its orbit around the sun. In the summer, the time between sunrise and sunset is longer than in the winter. The question is: "How much longer?" [...]  »

The MC6809E microprocessor is designed for use in a multiprocessor system.

[author : Hunter Scales] #Electronic #Listing #Assembly #Microprocessor #Algorithm

Extract : «  Recent years have seen microprocessors assuming applications previously targeted for minicomputers. Their cost and size advantages have spurred their inclusion in a variety of designs such as word processors, computer terminals, and cash registers. Where these functions were once implemented on minicomputers and timesharing terminals, microprocessors can now take on most of the burden in these jobs.

There are still many applications where microprocessors are too slow or are lacking in arithmetic power. However, microprocessors are so attractive from a cost standpoint that ways to use them in computation-bound problems are being intensively investigated. The sharing of resources by more than one processor spreads the cost of expensive programmable memory, mass storage, and peripheral devices. The percentage of utilization is increased, making these resources more efficient.

Multiprocessing (using more than one processor) is one way to accomplish this increase in use. The use of two or more microprocessors sharing common resources, each working on a portion of a problem, allows a microcomputer system to function where a minicomputer was needed previously — provided that the microprocessor can be used in a multiprocessor system. Motorola's new 8-bit microprocessor, the MC6809E, was designed with multiprocessing in mind. [...]  »

An electric-circuit model makes heat flow easier to understand.

[author : Daniel Doan] #Electronic #Listing #BASIC #Energy #Book

Extract : «  Energy consumption in the United States in 1979 exceeded 70 quadrillion Btus (British thermal units). That's a lot of energy. About 22% of that was consumed by residential space and water heating. If some of this energy could be supplied directly by the sun, the savings would be considerable.

This goal could be attained in part by thermal-solar-energy heating systems, but their design presents some problems. For example, what collector area would be most cost-effective? Does the building need more insulation? Can a storage tank hold enough energy to supply the building with heat thru a cold spell? A simulator program can help answer these and other important questions.

A computer program using heat-transfer equations can use numerical approximation to effectively simulate a solar-energy system. Program users can begin simulation with the parameters of their home and learn the effect of changes in these parameters on the efficiency of a hypothetical energy system. In this way, an economical system can be engineered for a particular building and location without costly experimentation.

A typical solar-heating system (figure 1) consists of a collector, storage tank, and pipes connecting these and the building. In this article, I consider only a circulating water system, keeping in mind that the concepts are similar for a hot air system. [...]  »

The principles of energy conservation can be applied to your home using a program written in PET (Microsoft) BASIC.

[author : David R Jackson and John M Callahan] #Listing #BASIC #Energy #Book

Extract : «  Many aspects of the present energy situation are beyond the control of the individual. There are, however, a few notable actions that you can take to lessen the impact: one is to conserve conventional fuels; the other is to find economical alternatives. In this article we will present several tools that can be used in conjunction with your personal computer — tools that will allow you to understand energy-use patterns, and change these patterns with sound technical and economic decisions.

We will begin by providing a background on heat transfer and how it governs the energy consumed in a building. After this information is presented, we will outline an example that demonstrates the calculation that you must perform to determine your yearly energy requirements for space conditioning. Included in this example will be a program that you can use to simplify these calculations. We will also discuss energy conservation options available to you and how to determine the economic payback to implement these measures. [...]  »

Predicting your cars fuel economy can alert you to mechanical problems.

[author : Jerry Lobdill] #Algorithm #Listing #HP #Energy #Book

Extract : «  Have you ever wondered how a heat-seeking missile homes in on its prey? How lunar landings are accomplished without dashing the lunar module to bits? Or how satellite orbits are predicted and adjusted? These and other complex problems have been solved through the powerful techniques of optimal estimation theory.

The roots of this discipline can be traced back to Karl F Gauss, who first used the technique of deterministic least squares in an orbit-measurement problem — circa 1800. Although Gauss recognized and discussed many aspects of the general problem of estimating the state of a dynamic system based on "noisy" measurements of observable quantities, it remained impractical to address the real-time statistical problem until 1960 when R E Kalman proposed optimal recursive techniques which can be easily implemented on digital computers. Today "Kalman filtering" problems involving ten to twenty variables are routinely solved in real time using microprocessor-based systems.

A complete understanding of the theory of Kalman filtering requires considerable familiarity with the theory of random processes, but the intuitive concept can be easily grasped by any interested person with some background in university-level mathematics. This article provides insight into the workings of a Kalman filter and at the same time it presents a useful algorithm that can be implemented on any personal computer. The problem addressed is simple to solve with Kalman techniques in that only one variable is involved—the gasoline mileage of your automobile. [...]  »

A decision-tree pruning algorithm greatly reduces the time needed to solve the traveling-salesman problem.

[author : Richard T Parry and Howard Pleffer] #Listing #BASIC #Mathematics #Book

Extract : «  You may not need a computer to tell you the shortest distance between two points, but you may need one if you are trying to find the shortest route from city to city when many are involved.

This problem is commonly known as the traveling-salesman problem and is referred to by mathematicians and computer scientists as an NP-complete (nondeterministic polynomial) problem.

The difficulty lies in the number of different routes a salesman can take from city to city. If only five cities are involved, the number of different routes is a manageable 4! (4 factorial or 24). But the number of routes increases exponentially. So with nine cities, for example, the number of routes jumps to 8! (5040). And with 12 cities, the number of possibilities for the trip reaches a staggering 40 million. That's a lot of calculations — even for a computer. In fact, it is not too hard to imagine a travelingsalesman problem that would take the world's most powerful computer centuries to solve.

The fact that NP-complete problems take so long to solve is both a burden and a blessing. The obvious disadvantage is that it is difficult or impossible to solve some very useful problems. But it is a blessing as well since it lends itself to the design of systems to encode information for security purposes. This fact comes at a time when computer fraud is increasing.

Interestingly, the traveling-salesman problem was discussed in an article entitled, "What Computers Cannot Do " (BYTE, January 1980, page 100). Indeed, there is no known way, at present, to solve all traveling-salesman problems in a simple and elegant manner or in a relatively short time. [...]  »

Pascal support of the standard operational features of the Micromodem II.

[author : Scott G Robinson] #Listing #Pascal #Interface #Networks

Extract : «  When I added Apple Pascal to my Apple II Plus system, I discovered that a few of my peripheral-device cards not made by Apple Computer Inc didn't work under the system. One was the Hayes Microcomputer Products Micromodem II directconnect modem. Although the Pascal BIOS (basic input/output system) recognizes the Micromodem as a communication card, the BIOS does not contain the software necessary to control the modem's operations.

In BASIC, I could easily call and communicate with other modem-equipped systems, or have them call me. In Pascal, my system can't answer the phone even though the REMIN: and REMOUT: device names are associated with the Micromodem I/O card. This happens because BIOS doesn't use the Hayes modem's on-card firmware as Apple's DOS (disk operating system) and monitor ROM (read-only memory) do.

Various solutions were possible. In the February 1981 issue of BYTE, Thomas H Woteki described an Apple Pascal support procedure for the Hayes modem. (See "A Pascal Library Unit for the Micromodem II," page 106.) His method included modifying the BIOS routines in the SYSTEM.APPLE disk file and using a fair amount of machine-language routines. I decided against modification of the BIOS to maintain program compatibility with other Apple Pascal users. By using a programming trick that permits direct examination and modification of memory locations from Pascal, I knew I could reduce the amount of machine-language code needed. The final solution was to write a set of Pascal routines to supply some of the original Hayes modem firmware's services and use them in programs as needed. [...]  »

A variation on the game of Life that introduces the concept of a cellular hereafter.

[author : Pat Macaluso] #Listing #BASIC #APL #Simulation

Extract : «  In the conventional game of Life, death is final, and birth is the beginning. Cells simply vanish when they die, and they appear magically out of nowhere when births occur. The void on both ends saddened me. I could not accept Life without hope or a spiritual dimension. The result is Life After Death. After all, we create the microcosms known as cellular automata and make the rules known as state transitions. We can just as easily change the rules. If we want a cell to have an existence in the hereafter, then so be it.

In Life After Death, cells that die pass on to another state of existence; they enter a netherworld. Likewise, when a birth occurs, a cell from the other world descends to become the newly born cell, a gift from cell heaven or a reincarnation, if you will. More on this later.

The idea behind Life After Death is to explore Life systems with a view to generating interesting moving video displays or attractive printed patterns. This kind of study, however, poses several problems. One is the time and effort required to modify algorithms for new Life systems. A second problem is the slow execution of high-level interpretive languages. (Few of us have the time or inclination to tackle such studies in machine language or assembly language.) A third problem is the difficulty involved in analyzing results and manipulating output. This article illustrates one approach to simplifying these problems. It also suggests the many structures and rules that can be readily implemented.

A good starting point is offered by Jonathan Millen in "One-dimensional Life" (BYTE, December 1978, page 68). One-dimensional Life is easy to program in high-level languages. It also runs fast enough for study purposes. [...]  »

Special routines link the Apple Graphics Tablet to UCSD Pascal in this computer-aided-drafting project.

[author : Dan Sokol] #Listing #Assembly #Pascal #Electronic #Graphics

Extract : «  Electronic hardware design, like any creative endeavor, has its high points and its low points. A personal low point has always been the time it takes to draw usable schematics. The problem is compounded when you consider that after the schematic is drawn and the hardware prototyped, the schematic must be modified (in any number of colors) as the circuit is debugged. Then, of course, the circuit has to be redrawn. And usually by me.

At a trade show a few years ago, I saw a high-quality graphics terminal that was used with a light pen to draw schematic diagrams. A menu of devices was available from the keyboard, and the light pen was used to place the selected device on the screen. Fantastic! ... and only $150,000.

Technology marches on. Some time ago, Apple Computer announced a new product — a Graphics Tablet. My Apple already had Pascal and an M & R Enterprises Sup'r'terminal board, so I only needed the Graphics Tablet (and some software) to build a computer-aided drafting system (see photo 1).

I began the project with a great deal of enthusiasm. Being fairly proficient with Pascal, I did not anticipate any major problems. It was only after I read the fourth page of the Graphics Tablet operation manual that I began to realize I might have bitten off more than I could compile. It read, "... the Graphics Tablet software will not operate ... in an Apple Pascal environment" I immediately called the Apple Software Hotline (408-996-9868).

Fortunately, the people at Apple were very helpful. They explained that the reason the tablet would not interface to Pascal was that the Pascal BIOS (basic input/output subsystem) did not recognize its existence. They sent me a copy of the BIOS initialization routines, from which I was able to write an assembly-language linkage routine to read data from the pad and transfer it back to Pascal. (Not one to dwell on failures, suffice it to say that it took me three weeks of experimentation to reach that point.) [...]  »

[author : Robin B Moore] #Devices #Software #Audio #Review

Extract : «  You've probably heard them at computer shows or in the local computer store — the music synthesizer peripherals that, along with your Apple II computer, can help you "compose," "turn your Apple into a family music center," or offer "flash and crash sound effects." Six or seven music synthesizers are already available for the Apple II, and in this article we'll examine the most significant new entry into the marketplace — the Mountain Computer MusicSystem — and see how it compares with the competition.

Mountain Computer (formerly Mountain Hardware) is a well-known manufacturer of high-quality Apple peripheral products that have been well received by the Apple-user community. Mountain Computer's products have never been cheap, and the MusicSystem is no exception. At $545 it is one of the more expensive music synthesizers available for the Apple II, and yet, when its capabilities are considered, it costs less than some of the lower-priced units. No other Apple synthesizer on the market offers sixteen programmable waveforms, and the most popular "square-wave" unit, the ALF AMS (by ALF Products, of Denver, Colorado) can cost as much as $795 when expanded to its maximum (nine voices).

Unlike many of the less-expensive music boards that are available for the Apple II, the MusicSystem is a true synthesizer in the sense that a Moog or an ARP is a synthesizer. The user can not only specify the frequency and the amplitude envelope for each note, but also the waveform, waveform variation (within certain limits), and frequency variations during each note. This allows for a simulation of real instrument sounds that is impossible to achieve with a fixed-waveform music board.

The MusicSystem

The MusicSystem is a combined package of hardware and software that allows the user to enter and edit musical scores, to create and edit instrument definitions, and to combine both scores and instruments into PLAY files that produce the final musical output. [...]  »

[author : Mark Pelczarski] #Software #Review #Programming

Extract : «  The Atari Assembler/Editor plug-in ROM (read-only memory) cartridge is finally available. Anyone who plans to use or learn 6502 assembly language on the Atari 400 or 800 computers will find it a convenient tool. It is especially nice for beginners, since some of the editing and programming features of Atari BASIC are available. The Atari people point out that this assembler is not designed for professional programmers, although they do use it for much of their in-house programming. They describe it as an experimenter's assembler designed for those people writing machine-language subroutines to supplement their BASIC programs when speed, sound, or graphics are factors.

Overview

The Assembler/Editor package includes the cartridge and a user's manual. The cartridge actually contains three programs: the Writer/Editor, the Assembler, and the Debugger/Mini-Assembler. The cartridge will operate with either a cassette-tape drive or a floppy-disk system, but the disk gives more versatility. The cartridge plugs into the left slot in the Atari 800, and it occupies the upper 8 K bytes of user-accessible memory-address space. [...]  »

[author : Yvon Kolya] #OperatingSystem #Review

Extract : «  Percom's Doubler, an add-on circuit board that allows your TRS-80 to store and retrieve data from the Radio Shack disk drives in double density mode, has been on the market for almost a year now (see the review "Percom's Doubler" on page 344 in this issue of BYTE). The board comes with Percom's Double-DOS (disk operating system), an adaption of Radio Shack's TRS-DOS that lets you use the doubler board without buying a DOS from another source. [...]  »

[author : Mahlon G Kelly] #Devices #Software #Review #Storage

Extract : «  Did you ever wish that you had an 8-inch floppy-diskdrive system, 80-track drives, or even a hard disk for your (Radio Shack) TRS-80 Model I?

Granted, disks were a great improvement over cassette tape for storage of programs and data, but many of us quickly found that even disk storage was limiting. Consequently, we bought additional drives but still wanted more storage than was available on each drive. Few of us could afford to trade in our old drives on the new, larger units, and many experimenters read about double density drives and sighed wishfully, "Why didn't Radio Shack make the Model I a double-density system?"

A single-density drive expects that much of the data stored on the disk is in the form of null characters. With the older recording heads and disks this practice was necessary. Removal of the null characters can improve storage capacity by 80% (and effect an equivalent change in the data transfer rate). This is called double density, and, in theory, by changing the LSI (large-scale integration) disk-controller device and the DOS (disk operating system) software, it should work with the TRS-80. [...]  »

[author : Mark Pelczarski] #Devices #Software #Display #Review

Extract : «  If you plan to use your Apple II computer for word processing and are looking for a lowercase adapter, the Videx Keyboard and Display Enhancer may be your answer. Several adapters allowing an Apple to display lowercase letters on the screen are available. But a problem occurring with most Apple word-processing systems, or any software using uppercase and lowercase, is that the Apple keyboard does not recognize most shifted keys. It will, for instance, identify I and shift-I as the same character, even if you wanted one of them to be lowercase. The most popular adaptation has been to use the ESC (Escape) key as a pseudoshift. When ESC is pressed, a character is actually sent to the computer. Therefore, most text editors have required any character you want capitalized to be preceded by an Escape character. If you wanted the word HUMBUG in all capitals, you'd have to type ESC, H, ESC, U, ESC, M, ESC, B, ESC, U, ESC, G. This tedious process is necessary with most other lowercase adapters because they modify only the display, not the input from the keyboard.

The Videx Keyboard and Display Enhancer modifies both the display and the keyboard input. It uses a jumper to the keyboard ROM (read-only memory) to allow acceptance of standard shift-key operations, and it displays uppercase and lowercase letters on the screen. With this device, you can use an Apple as you would a typewriter. In addition, the Enhancer allows you to change RESET to work only when the CTRL (Control) key is pressed, a useful safety feature for people with early-production Apples. It also allows you to remap character sets by modifying the 2716 EPROM (erasable programmable ROM) included on the board. [...]  »

#Book

The Architecture of Pipelined Computers, Peter M Kogge. New York: McGraw-Hill, 1981; 16 by 24.5 cm, 334 pages, hardcover, ISBN 0-07035237-2, $27.95.

The Art of Computer Programming, Volume Two, Second Edition, Donald E Knuth. Reading MA: Addison-Wesley, 1981; 16.5 by 24.5 cm, 688 pages, hardcover, ISBN 0-201-03822-6, $25.95.

Basic Computer Logic, John R Scott. Lexington MA: D C Heath & Company, 1981; 16.5 by 23.5 cm, 233 pages, hardcover, ISBN 0669-03706-0, $21.95.

Computer Systems Performance Modeling, C H Sauer and K M Chandy. Englewood Cliffs NJ: Prentice-Hall, 1981; 18.5 by 24.5 cm, 352 pages, hardcover, ISBN 0-13-165175-7, $18.95.

Data File Programming in BASIC: A Self-Teaching Guide, L Finkel and J R Brown. New York: John Wiley & Sons, 1981; 17.5 by 25.5 cm, 338 pages, softcover, ISBN 0-471-08333-X, $9.95.

8080/Z80 Assembly Language: Techniques for Improved Programming, Alan R Miller. New York: John Wiley & Sons, 1981; 17.5 by 25.5 cm, 318 pages, softcover, ISBN 0-471-08124-8, $9.95.

Essentials of Project Management, Clifford F Gray. Princeton NJ: Petrocelli Books, 1981; 16.5 by 24.5 cm, 241 pages, hardcover, ISBN 0-89433-101-9, $17.50.

Formal Specification of Programming Languages: A Panoramic Primer, Frank G Pagan. Englewood Cliffs NJ: Prentice-Hall, 1981; 16 by 23.5 cm, 245 pages, hardcover, ISBN 0-13-329052-2, $19.95.

How to Get the Most from Your Chess Computer, Julio Kaplan. Great Neck NY: RHM Press, 1980; 13.5 by 20.5 cm, 138 pages, softcover, ISBN 0-89058-046-4, $8.95.

Information Processing Systems, Second Edition, William S Davis. Reading MA: Addison-Wesley, 1981; 20 by 24.5 cm, 504 pages, hardcover, ISBN 0-20103183-3, $18.95.

Inside BASIC Games, Richard Mateosian. Berkeley CA: Sybex, 1981; 18 by 23 cm, 325 pages, softcover, ISBN 089588-055-5, $13.95.

Interactive Videotex: The Domesticated Computer, Dimitris N Chorafas. Princeton NJ: Petrocelli Books, 1981; 16.5 by 24.5 cm, 263 pages, hardcover, ISBN 089433-127-2, $21.95.

Karel the Robot, A Gentle Introduction to the Art of Programming, Richard E Pattis. Somerset NJ: John Wiley & Sons, 1981; 16.5 by 23 cm, 106 pages, softcover, ISBN 0-471-08928-1, $5.95.

Man-Machine Systems: Information, Control, and Decision Models of Human Performance, T B Sheridan and W R Ferrell. Cambridge MA: MIT Press, 1981; 15.5 by 23 cm, 452 pages, softcover, ISBN 0-262-69072-1, $12.50.

MICRO/Apple, Ford Cavallari. Chelmsford MA: Micro Ink Inc, 1981; 16 by 23 cm, 216 pages, softcover, ISBN 0-938222-05-8, $24.95. All the programs introduced in MICRO/Apple are on a 5-inch floppy disk (DOS 3.2 format), which accompanies the book.

Oscilloscopes, S Prentiss. Reston VA: Reston Publishing, 1981; 16 by 23.5 cm, 161 pages, hardcover, ISBN 0-8359-5354-8, $16.95.

Pascal Primer, D Fox and M Waite. Indianapolis IN: Howard W Sams & Company, 1981; 22 by 28 cm, 208 pages; softcover, ISBN 0672-21793-7, $16.95.

6809 Assembly Language Programming, Lance A Leventhal. Berkeley CA: Osborne/McGraw-Hill, 1981; 16.6 by 23.5 cm, 553 pages, softcover, ISBN 0931988-35-7, $16.99.

68000 Microprocessor Handbook, Gerry Kane. Berkeley CA: Osborne/McGraw-Hill, 1981; 18 by 23.5 cm, 113 pages, softcover, ISBN 0-931988-41-1, $6.99.

Software Maintenance Guidebook, R L Glass and R A Noiseux. Englewood Cliffs NJ: Prentice-Hall, 1981; 15.5 by 23.5 cm, 193 pages; hardcover, ISBN 0-13-821728-9, $21.95.

Stalib, A Statistical Computing Library, W M Brelsford and D A Relles. Englewood Cliffs NJ: Prentice-Hall, 1981; 21 by 28 cm, 427 pages; softcover, ISBN 013-846220-8, $17.50.

Structured Requirements Definition, Ken Orr. Topeka KS: Ken Orr & Associates, 1981; 24.5 by 28 cm, 236 pages, softcover, ISBN 09605884-0-X, $25.

Understanding FORTRAN, Second Edition, M Boillot. St Paul MN: West Publishing, 1981; 18.5 by 25 cm, 505 pages, softcover, ISBN 0-8299-0355-0, $14.95.

Using BASIC, R Didday and R Page. St Paul MN: West Publishing, 1981; 18.5 by 25 cm, 525 pages, softcover, ISBN 0-8299-0357-7, $15.95.

When People Use Computers, Marilyn Mehlmann. Englewood Cliffs NJ: Prentice-Hall, 1981; 16 by 23.5 cm, 142 pages, hardcover, ISBN 0-13-956219-2, $15.

Why Do You Need a Personal Computer? , Lance A Leventhal and Irvin Stafford. New York: John Wiley & Sons, 1981: 17.5 by 25.5 cm, 278 pages, softcover, ISBN 0-471-04784-8, $8.95.