IBM 560 Computer Monitor User Manual


 
Attention
The term
Reserved
describes certain signals, bits, and registers
that should not be changed. Use of reserved areas can cause
compatibility problems, loss of data, or permanent damage to the
hardware. When the contents of a register are changed, the
state of the reserved bits must be preserved. When possible,
read the register first and change only the bits that must be
changed.
viii ThinkPad 560/560E Preface