Classic Computer Magazine Archive ANTIC VOL. 2, NO. 7 / OCTOBER 1983

Tangle Angles


You previously stated that increasing the baud rate of the cassette load makes things go kaput. Enclosed you will find a bootload tape program, called Cassabauda, that will increase baud to 820 and function as reliably as the regular 600 baud. I'm selling it here in Hawaii for $7.50.

Also, are you aware you can have a sort of "double-density" tape format? The ATARI OS will support records up to 256 bytes, but the current cassette handler deals in 132 bytes. This could be a great way to protect commercial tape programs.

Del Wong
Honolulu, HI

I tried the Cassabauda utility program, and it does indeed increase the cassette baud rate as you claim. I note that you chose a default baud rate of 820. I experimented with varios baud rates using your program and found that 820 baud was the maximum rate that still gave reasonable reliability. Even your program did not cause the system to work reliably at 900 baud. Still, 820 baud is 36 percent increase in speed, a good thing to have.

The record-length change you mention is currently being used by a number of cassette program companies to "Protect" their software from being copied. Most of them don't use the full 256 data bytes per record, however. The ones I have analyzed typically use a number in the 140 to 150 range.

Why are there 18 seconds lead time for cassettes? Is there some way to shorten this? What is the difference between BAUD and bits per second?

AI Jacobs
Silver Springs, MD

The leader tone on a cassette tape file is set by the Operating System to about 20 seconds. There is no good reason that it has to be that long. You can change the Iength of the Ieader tone, but you can only do this with machine language. I plan on writing about this sometime this year. I will give you a BASIC POKE program that will put such a machine language in memory. Infact, I probably will include a baud-rate control routine in the same program.

The word BAUD, like many scientific words, has a bit of history behind it. It commemorates a famous 19th-century, French pioneer in telegraphic communications: J.M.E. Baudot. The "baud" was the unit of measure for transmission speed for serial data communication. It represented the number of half-dot cycles transmitted continuously in one second (the modulation rate). Modulation rate can be thought of as rate of which a carrier wave is adjusted to accodate data transmission. In present day usage, the data-signalling rate (measured in bits per second) is usually equal to the modulation rate (expressed as baud). Thus the number of bits transmitted per second is equal to the baud rate. In our situation of asynchronous data transmission, the baud rate is equal to the bit rate when one stop bit is used.

I recently bought FROGGER on cassette for cassettes from Sierra On-Line, but can't get it to load. I followed the instructions (no BASIC, turn computer on while pressing [START]. The recorder starts, but a BOOT ERROR message soon appears. I have tried everything. I took the tape back to the store, and it loaded okay there. I have no trouble loading other tapes, including my own. I have an older 410; could that be the problem? If so, is there anything I can do?

Carlos Ojeda
Monterey Park, CA

If you aren't having the same kind of problem with any other tapes, the probable cause is that the tape may be only a marginally good recording. If so, it might not load on the older 420 recorders. Take the tape and the recorder to the computer store and try loading thr tape with your rocorder and their computer. I would almost bet that it won't load. If this indeed the case, then I suggest you try the HI-REL modification I described in ANTIC, April 1983. The schematic of the 410 also appears in the issue.

There are diffences between the older 410 recorders and the newer ones. I have personally seen at least four completly different types. The first thing, and the most important, is that only the newest 410s have five percent resistors in them. All of the older recorders have ten percent resistors. This is most likely cause of your loading problem. In addition, there are subtler differences that are not ohvious. The circuit board layout and the motor housings vary depending upon where and when the recorders were made. The better ones were made in Japan. If you have one of those made in Hong Kong, let's just say that they are not the same. Incidentally, the newer 1010 recorders are made in Hong Kong.