Help Wanted
Dear Editor:
I need some help with a MicroAce. The K inside the cursor keeps rolling and the unit will not respond to keyboard commands. I have attempted to trouble-shoot it by chip substitution with no luck so far.
Peter Beck
[address omitted]
Denville, NJ
Dear Editor:
I have noticed that saving programs on cassette from my ZX81 results in some buzzing sound which is recorded at the beginning and end of programs. Experience shows that this causes some problems when reloading the programs.
Is there any way or any hardware modification that will get rid of this buzz?
Ho Tiap Fen
[address omitted]
Bandar Seri Begawan
Brunei
New Product Problems
Dear Editor:
My first computer was, and still is, a 2K MicroAce. Now with the vast (relatively speaking) amount of peripherals available for the ZX81, I am seriously considering upgrading it significantly.
The problem, however, is that many of the ads in SYNC do not indicate whether or not the products are compatible even with the ZX80, let alone the MicroAce, even though they are all essentially the same machine with various internal differences. I realize that I will have to install an 8K ROM.
Please publish an article indicating what peripherals are directly compatible and what modifications can be done to adapt those not interchangeable between the ZX81 and the ZX80/MicroAce.
William E. Allen
[address omitted]
Metairie, LA
Ed.—Since the number of ZX81s out there is significantly more than the ZX80 type, most advertisers are naturally aiming at the larger market. If a ZX80 or MicroAce owner sees a peripheral or program of possible use, the best bet would be to contact the advertiser directly find out whether that product is compatible. We would welcome seeing an article providing the kind of analysis suggested.
Dear Editor:
Congratulations! It is good to see that someone has a magazine devoted to the Sinclair line of computers. Before I buy a computer though I want to know if it has programs to do what I want it to do. Do you know or can you find out if there are programs for: speed reading, analyze and predict the stock market performance of any particular stock, an electronic circuit designer, analyze and predict the winner of a horse race, and a program generator?
I need someone to give an impartial view. Can you?
Carlos Urrutia
[address omitted]
Gregory, SD
Ed.—Your best source of information on programs is our ad pages. Each issue brings new products as well as continued offerings of previous products. Through our reviewers we try to give a fair evaluation of products and programs. However, we have not run any reviews comparing programs for the Sinclair computer series with similar programs for other computers except perhaps as a point of reference. Help is on the way, though, because we are planning to publish a comprehensive buyer’s guide for products for the Sinclair and Timex/Sinclair computers. See SYNC Notes in this issue for further details.
Dear Editor:
As the ZX81 becomes more popular, hardware and sofware from different vendors is flooding the market. Many perform the same function or offer the same type of software.
How is the average consumer supposed to know which product is best for his applications and which is the better buy if there is no information available?
In the near future does SYNC plan to give honest, in-depth reviews on all new products for the Sinclair machines?
Sheree Draft
[address omitted]
Boston, MA
Ed.—We cannot review all new products; there are just too many. This is why we have invited reviews from users who have had extended experience with a given product and why we prefer comparative reviews whenever possible. We also expect such reviews to be honest and in-depth. The increase in space devoted to reviews will provide more extended product information.
Dear Editor:
In an age when merchandisers often are thought of as rip-off experts, I would like to salute one of your advertisers.
When it comes to fast service, prompt replacement, and helpful information, Peak Software of San Carlos, CA, rates at the top of my list.
A goodsized segment of any industry could take customer relations lessons from David Farrell of Peak.
Robert J. McGarvey
[address omitted]
Kendal Park, NJ
Elimination
Dear Editor:
The Elimination Game in SYNC 2:5 can be used by unexpanded ZX81 users with a few changes. The original program uses a numeric array which requires over 50 bytes to store and a FOR-NEXT loop to print. The change uses strings to store the numbers (1 byte per character) instead of the array (5 bytes per character). Strings are ideal for storing numerical data from 0 to 9 because they are completely flexible in length and PRINT much faster.
The rules of the game are the same except that to terminate the game after a loss 0 is entered. Any other invalid number will begin the turnover from the roll. If more than one number is required to complete the roll, a total is given.
By the way, I am in the process of learning machine language, and, although I have a ZX81, I would like my machine code programs to run flicker-free on an 8K ZX80. Isn’t there a subroutine in the ROM to display a frame to the TV?
Michael B. Williams
[address omitted]
Virginia Beach, VA
Elimination in 1K
Type in the program, hit RUN and ENTER.
The numbers 1 to 9 will appear with a number representing a dice roll. Choose which number or numbers you wish to eliminate. Your choices must equal the number rolled. The object of the game is to eliminate all the numbers. When the end of the game is approaching, a roll higher than the total left in the display will end the game. The lowest number wins. To play again hit ENTER.
10 RAND
20 LET A$=" 1 2 3 4 5 6 7 8 9"
30 LET R=INT (6*RND)+INT (6*RND)+2
40 LET T=0
50 LET B$=A$
60 CLS
70 PRINT "NUMBERS TO ELIMINATE"
80 PRINT AT 4,0;"ROLL ";R
90 PRINT AT 2,0;B$;" "
100 INPUT N
110 IF NOT N THEN RUN
120 IF ABS (N-5)>4 THEN GOTO 40
130 IF B$(N+N)<>STR$ N OR NOT CODE B$(N+N) THEN GOTO 40
140 LET T=T+N
150 IF T>R THEN GOTO 40
160 LET B$(N+N)=""
170 PRINT AT 4,11;"TOTAL ";T
180 IF T<R THEN GOTO 90
190 LET A$=B$
200 IF A$<>" " THEN GOTO 30
210 PRINT AT 0,0;"WINNER***************"DEF and PAUSE
Dear Editor:
The article on DEF in SYNC 2:4 was very informative, especially for one using programs involving many repetitious mathematical expressions. However, the two programs used to demonstrate the use of A$ and F$(X) with VAL were too slow even in FAST. I would suggest a better program to illustrate the simulation of DEF FNA(X) on the ZX81.
Furthermore, if line 190 were written PRINT AT 23,10;F$(B), there would have been space on the bottom of the screen for a REPORT or CURSOR and the run could have been stopped any time by hitting BREAK as usual. Also, this would have eliminated the need for the fancy, and limited use of lines 330 to 370.
Alger Salt in SYNC 2:3 expains why he had to take extra steps to get around an idiosyncrasy in the Sinclair computer when the PAUSE function is used. I would suggest avoiding the use of PAUSE whenever possible and substituting a conventional FOR-NEXT loop instead. For example:
FOR N = 1 TO 50
NEXT NPAUSE (at least on my TV screen) has another undesirable characteristic. It causes the image to jump. This is very disturbing in graphics. The do-nothing, FOR-NEXT loop does not impart any motion to the screen.
I use PAUSE mostly with, say PAUSE 40000, to get an indefinite delay in the run of a program. Then press any key except BREAK to continue. Another plus is the fact that the screen does not clear first when the program restarts.
Warren Fricke
[address omitted]
Depew, NY