Classic Computer Magazine Archive COMPUTE! ISSUE 58 / MARCH 1985 / PAGE 159


Modificatons Or Corrections To Previous Articles

VIC TurboTape
In both the VIC and 64 versions of this highspeed tape utility from the January 1985 issue (p. 124), location $8B (139) is used for temporary storage. On both computers this is the first of five bytes ($8B-$8F) that hold a seed value for the random number generator. TurboTape's use of this location does not appear to cause problems for the 64, but it introduces a bug in the VIC version with some programs. When a program containing the function RND(1) is Turboloaded and run, an ?OVERFLOW ERROR results because the Turboload routine leaves a value in $8B that produces a random number that is too large.
    There are several simple ways to prevent this. First, you could change all occurrences of RND(1) to RND (-TI) so that the random number generator will take its seed value from the software timer. This should not significantly alter the operation of any program using random numbers. Alternatively, reader Brian Mason notes that you could add the statement POKE 139,128 before the first RND(1) to return location $8B to its proper value. If you'd like to change VIC TurboTape itself so that this problem is avoided, Joseph Kovalik suggests changing all references to location $8B to the otherwise unused location $FB. To accomplish this, change the following lines in the generator program (Program 2) and create a new version of TurboTape to replace the existing one:

                                  :rem 69
4859 DATA 173,28,145,133,251,9   :rem 215
4907 DATA 28,145,133,251,9,12    :rem 153
4997 DATA 207,252,165,251,141,28  :rem 57
5201 DATA 252,165,251,141,28,145  :rem 37

JTERM For Atari
Several readers have complained that lines 490, 510, and 590 of this telecommunications program from the January 1985 issue (p. 145) are too long to type in. The simple solution is to omit all spaces between the BASIC statements in those lines. For example, Atari BASIC sees no difference between POKE 702,64:INPUT SPOOL$ and POKE702,64:INPUTSPOOL$. Leaving out the spaces doesn't affect the Automatic Proofreader checksum values either, since the Proofreader ignores all spaces except those within quotes. When you list the lines, the screen editor will add spaces between the BASIC keywords so the lines will be easier to read.
    The JTERM program cannot be used with the new Atari 1030 modems, since these are handled by the computer as the T: device. JTERM is designed for communications via the R: device, the designation of the older Atari 850 Interface Module to which the Atari 830 and other standard RS232 modems are connected.

Atari Paratrooper
Line 11 of this game from the January 1985 issue (p. 70) has the same line-length problem as JTERM, and the same solution applies. Simply omit all spaces between the statements.

TI Guitar Tuner
Line 280 of this music utility from the January 1985 issue (p. 100) is acceptable in Extended BASIC, but is too long to be typed in with regular console BASIC. To remedy this, break the line into two parts as shown:

280 A=-(A$="e")-2*(A$="a")-3*(A$="d
285 A=A-10*(A$="G")-11*(A$="B")