User`s manual

The problem is compounded when a person runs programs in the
“background”. TSR programs like SIDEKICK

and others steal time
during interrupts or key presses. This means you have less time to
be able to receive a character.
A poorly designed TSR program running at the same time may
prevent interrupts from being serviced and you may even miss char-
acters (which is always fatal) when you are “reading” an eprom.
Programming eproms is less critical, since the transmit side of
PGMX is not interrupt driven. This means the error message you
receive about missed characters is only the echo of what was sent
to the 9000. However, if that character was an asterisk (* ), you might
miss the error message that follows. PGMX will eventually “time out”.
Unless you “fix” the problem by reducing the baud rate or running
without the TSR programs installed, it might happen again.
Chapter 4 Diagnostics Model 9000
Page 20