Commodore PET User Manual page 182

Because of the size and type of keys used for the small PET keyboard, vou
may encounter minor data entry problems if Vou try to type fast on the small
keyboard. These problem areas are described in detail below. If vou
have
a full
size PET keyboard. vou might proceed to the next section, "The Keyboard Buffer."
Two-Key Rollover (Small Keyboard)
There are areas on the compact PET keyboard which do not give predictable
results during rollover. The space key on the bottom row (a SPACE character is in-
dicated hereafter by the symbol "11f') is cou pied with the keys directly to the left
and right. giving incorrect results.
cou pied
~
B~mrn lYJ~BJ
When the RIGHT BRACKET [j]key and the SPACE key to its left are pressed
simultaneously:
correct roi
lover
should print:
] t6
but the PET often prints:
]<16
or ]
16 <16
The key coupling erroneously puts the"
<"
character (to the right of the
"115"
key)
and sometimes and extra
"115"
into the buffer. The same problem occurs when the
keys are reversed:
Instead of printing:
] t6
the PET often prints:
<16]
or
16 t6 <]
The
above
examples show that rollover should not be depended upon
when typing on the bottom row of the small keyboard due to the coupling
problem with the SPACE key. But the rest of the small PET keyboard can be
depended upon for two-key rollover as a valuable safeguard against losing
keystrokes.
169