Micro Mechanic
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Mattel Aquarius Benchmark
I am writing in response to your article in the January 1985 issue of COMPUTE! on the subject of MSX. My letter is actually based on my own applications with a recently purchased Mattel Aquarius system, and my frustrations in obtaining support, literature, and peace of mind in my attempt to decipher this elementary unit.
! ran your test program on my Aquarius (thank you for listing it in plain vanilla), and was quite surprised to find that it executed in only 4:35! Perhaps you might know why this is possible? The Aquarius uses the Zilog Z80 central processing unit, and it has a clock speed of only one megahertz.
I would truly appreciate any information or ideas in my attempt to crack the graphics, sound, machine language, etc., on my Aquarius.
Paul A. Linck
Your timing of 4 minutes and 35 seconds, if accurate, is indeed impressive—it places the Aquarius ahead of the fastest computer in the benchmark test, the IBM PC, which ran the program in 5:45.
We're at a loss to explain why the Aquarius is so fast at running this test. However, one factor may be the sparse BASIC, which can run faster because it isn't burdened by numerous extra commands. Also, no benchmark program is ever really a fair test for different kinds of computers; some benchmarks simply run better on some computers than on others. A different or slightly modified benchmark test might yield quite different results (as pointed out by columnist Bill Wilkinson in "INSIGHT: Atari," March 1985).
You don't say how much memory is installed in your Aquarius, but computers with less memory often tend to run faster than computers with more memory. Many users who have upgraded a machine from 16K to 48K or 64K have noticed that their favorite programs execute with just a little less zip. Recall how the Commodore VIC-20 placed near the top of the benchmark test—it has only 5K of RAM. Its 22-col-umn by 23-line screen also requires less screen memory than other computers, so the refresh time is shorter.
Unfortunately, we can't help you in your quest for detailed information about your Aquarius. Evidently you purchased it at a closeout sale. The Aquarius suffered one of the shortest lifespans of any computer—it zvas discontinued by Mattel almost as soon as it hit the store shelves, a victim of the 1983 home computer price wars.
Changing Device Numbers
We both have Commodore 1541 disk drives and would like to know if we can connect them to use as a dual disk drive.
Bill Russell and Don Campbell
That's very easy with the 1541 disk drive; just change the device number. The device number is used in commands like LOAD "PROG",8 where 8 is the device number of the disk drive.
There are two ways to change the device number of the drive—one by software, the other by cutting a jumper inside the drive itself. We'll assume you each want to continue using your drives independently at times, and just deal with the temporary device number change.
Changing the device number won't make your drives act as a Commodore 4040 dual drive, which is addressed with 0: and 1: for either drive 0 or drive 1. Your drives are still independent, they just have different device numbers. You cannot directly copy between the two drives as on a 4040 drive; you must use a copy program that moves the data between the drives via the computer.
To change the device number, first connect the main disk drive to the computer and attach the serial cable from the second drive to the spare plug on the back of the drive. (This is called daisychaining.) Now turn the power OFF for the drive you want to remain unchanged, and turn the power ON for the drive you wish to change.
Enter this short program:
10 INPUT "NEW DEVICE NUMBER";N
20 OPEN 15,8,15
30 FRJNT#15,"M-W"CHR$(119)CHR$(0) CHR$(N + 32)CHR$(N + 64)
40 PRINT#15:CLOSE15
Run the progratn and enter a number from 8 to 15. This number will be the one you use to access the drive. When you run the program, line 30 will cause the error light to blink, but you can ignore this.
Now test that the device number has actually been changed by reading the directory. Assuming you changed the device number to 9, enter:
then LIST to see the directory.
Noiv turn on the drive you previously turned off, and enter:
To save to or load from the second disk drive, use SAVE "filename",9 or WAD "filename",9. Also be sure to use the proper device number when OPENing and CLOSEing files.
If you would like to operate more than two drives, just connect the other drives and turn them on, one at a time, and rerun the device number change program listed above. Each drive must have a unique device number.
This change is only temporary. When you turn your drive off, this change is reset, and the drive will return to using a device number of 8 when you turn it on again. Consult your 1541 manual to see hozv to permanently change the device number of a drive.
NOV/YOU CAN PUT YOUR COMPUTER TO WORK
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