Paolo Amoroso's Journal

Turbo Pascal 3.0 for CP/M has a display issue I noticed on the Z80-MBC2 and V20-MBC homebrew computers. When using the development environment, text in the terminal remained stuck with boldface turned on.

It was enough to launch Turbo Pascal and execute any command (e.g. compiler Options), or exit Turbo Pascal, to turn on boldface and leave it stuck in the IDE, in CCP, and when running other programs. Everything went bold such as code in source files edited in Turbo Pascal, CCP command lines, and the output of transient programs.

The issue occurred under CP/M 3.0 on the Z80-MBC2 and CP/M-86 1.1 on the V20-MBC, both accessed from the Minicom terminal emulator under Crostini Linux on my Chromebox.

I tried ANSI and VT102 emulation in Minicom and run the Turbo Pascal configuration utility TINST to set the terminal to ANSI, but the issue persisted. The only workaround was to resize the terminal window, which reinitializes the display.

I posted to comp.os.cpm for help and learnt Borland left the terminal reset string blank in the ANSI entry, which thus doesn't reset text attributes.

The fix was simple. I run TINST, selected the ANSI terminal, and edited the definition to insert the following reset string via the option Send a reset string to the terminal (the corresponding escape code strings and descriptions are below the hex values):

$1b $63    $1b  $5b $32 $4a

ESC c      ESC  [   2   J
Reset      Clear screen

ESC c is not enough as it only resets the terminal but doesn't clear the screen. With the new string the text attributes are now properly handled and the terminal is no longer stuck in boldface after using Turbo Pascal.

#z80mbc2 #v20mbc #retrocomputing

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