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Mapping the Atari cover

APPENDIX THIRTEEN

XL/XE Enhancements And Bugs

First the Good News

The XL computers fixed several bugs in the 400/800 and added many enhancements including relocatable handlers, new poll and new graphics modes in BASIC. Now, the OS inserts an end of line (EOL) character in the printer buffer if there isn't one already there when you CLOSE the device. You don't have to force out the last characters in the buffer. Printer numbers P1 through P8 are also accessible now. When reading either a record that's too long or one truncated with an end of file (EOF). the OS inserts an EOL into the input buffer to pro- vide at least as much as the buffer can handle without an error, so data isn't lost. The screen will clear no matter what the cursor coordinates. The dis- play handler and screen editor no longer clear memory above RAMTOP, so any data such as player/missile graphics you have up there is protected, even when changing graphics modes. The cassette loading mechanics have been greatly improved by a change in timing values (see the XL manual for details).

Now the Bad News

The Revision B BASIC ROMs have several awesome bugs in them, pointed out to me by Matt Ratclitt (a fountain of knowledge about the XL) on the Gateway BBS, St. Louis, Missouri. If you PEEK(43234) and get 96, you have the bug-ridden B ROMs; write to Atari and ask them for a new C ROM cartridge. Here are some of the bugs Matt described: First, BASIC appends 16 useless bytes to the end of a file on saving. This is a cumulative pro- cess; each time you load and save the same program, another 16 bytes are appended. This can cause severe problems and errors like 164--truncated record. Make sure you have nothing good on your disk and try this: 10 PRINT FRE(0): SAVE "D:JUNK":RUN "D:JUNK" and watch your memory dwindle away, 16 bytes at a time! Even- tually, your system will crash. Now try this: Type CSAVE (even it you don't have a cassette) and turn up your TV volume--press RETURN after the beeps and listen; you'll hear the CSAVE tones. When the READY prompt reappears, turn the volume up even more. Hear that? It's the sound of the load still on! You'll have to type END or SOUND 0,0,0,0 to get rid of it. CLOAD has the same problem. This is a bug in both versions. not just the B ROMs. Another problem is the unaccountable error 9--string not DIMed-- occurring on the line where the DIM statement actually resides! When you do too many loads and saves, especially with files 16K or larger, your system will lock up. Don't fool around; get the new ROM, which is available on cartridge, Write to Atari Customer Relations, 390 Caribbean Drive, Sunnyvale, California 94088. (See Appendix 19 for a temporary fix.) The 65XE and 130XE use the Revision C ROMs, so you don't have to worry about these bugs. XL owners can type in Matts program from Appendix 19 to cure their woes until they get the proper chips or cartridge.

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