--- VRac.pm	2007/08/05 13:27:27	145
+++ VRac.pm	2007/08/05 17:59:29	158
@@ -3,7 +3,7 @@
 use warnings;
 use strict;
 
-use Carp qw/confess croak/;
+use Carp qw/confess croak cluck carp/;
 use File::Slurp;
 use Data::Dump qw/dump/;
 
@@ -29,6 +29,14 @@
 This project is homage to 8-bit computers in Croatia and former Yugoslavia
 from 1980-1990. Word B<vrac> means also I<wizard> in Croatian.
 
+This project should enable anyone with limited knowledge of perl and 8-bit
+arhitecture of some machine to write emulator in an afternoon. To achieve this,
+code is written is as cleanly as possible.
+
+Porting existing emulators should be especially easy: you need passive
+understaning of language in which emulator is written and you can be on your
+way C<:-)>
+
 =cut
 
 =head1 FUNCTIONS
@@ -193,9 +201,21 @@
 	my $path = shift || confess "no path?";
 	my $bytes = join('', @_);
 
+	my $size = -s $path || 0;
+	my $len = length($bytes);
+
 	open(my $fh, '>>', $path) || confess "can't open $path: $!";
+	print($fh $bytes);
+	my $pos = tell($fh);
+
+	my $expected = $size + $len;
+	if ( $pos != $expected ) {
+		cluck "BUG: file grows too big got $pos, expected $expected !";
+		truncate $fh, $expected;
+	}
+
+	close($fh);
 
-	print $fh $bytes;
 	warn sprintf("## append_to_file('%s',%s)\n", $path, dump($bytes));
 }
 
@@ -346,7 +366,7 @@
 
 =head1 SEE ALSO
 
-Components: L<M6502>, L<Z80>, L<Screen>, L<Tape>
+Components: L<M6502>, L<Z80>, L<Screen>, L<Tape>, L<Session>
 
 Emulators: L<Orao>, L<Galaksija>
 
@@ -354,10 +374,13 @@
 
 Dobrica Pavlinusic, C<< <dpavlin@rot13.org> >>
 
-=head1 BUGS
-
 =head1 ACKNOWLEDGEMENTS
 
+Structure and Interpretation of Computer Programs by Abelson, Sussman, and
+Sussman L<http://mitpress.mit.edu/sicp/> is a great book. It gave me idea
+that you should have wizard powers over your computer, even if it's 8 bit
+one.
+
 =head1 COPYRIGHT & LICENSE
 
 Copyright 2007 Dobrica Pavlinusic, All Rights Reserved.