                     >>>>>  DoubleDuty  <<<<<
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Release 2.6.0

This release incorporates two changes which are beneficial to users with
Model 4's equipped with external memory add-on boards and modifications
to the DOS @BANK supervisor call to ewnable bank switching the external
memory (memory banks above 128K). One change is technical in nature; it
relates to the methods used by DoubleDuty to save and restore the video
screen images and the keyboard speed buffer. The second change adds a
parameter so that you may select the adjacent pair of memory banks used
by DoubleDuty. This change adds the BANK=b parameter. A normal 128K
Model 4 has three memory banks: 0, 1, and 2. DoubleDuty normally uses
banks 1 and 2 (0 is always used as part of the 64K address space of a
TRS-80). If you wish to use a higher pair of memory banks for DoubleDuty,
say 9 and 10, then invoke DoubleDuty with the parameter (Bank=9):

          DDUTY (Bank=9)

This will cause DoubleDuty to use memory banks 9 and 10. Bank will default
to "1" if you do not enter the parameter at the DOS command line. You can
determine if your machine has banks of memory above 128K known to the DOS
by use of LS-DOS 6.3.1's MEMORY command; it displays a map of known banks.

One use to be made of this feature is to enable DoubleDuty partitioning of
a Model 4 so that one of the partitions still has access to the first 128K
such that programs like MultiPlan may still have a larger buffer.
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