Transient Program Area (Tpa); Disk Drive Selection - LSI M-Three Operator's Manual

"'(his prompt shows that Disk Drive A has been selected (see 5.4) and
an operator input is required, as follows:
CP/M Version
*.*
56K Version
@.@
A>
(*. *
Operating System version number)
(@.@
M-THREE implementation version numberl
(56K see 5.3)
The CCP module, which provides an interface between the operator
and the system, thereafter interprets recognisable keyboard entries
and initiates the appropriate program within the BOOS moduie.
These keyboard entries must either be made at the correct time,
i.e. when 'prompted', or be of a special kind which will cause the
present activities of the M-THREE to be interrupted, e.g. Control-C.
for more specific information regarding the actual CP/M commands,
consult the CP/M manual available from Digital Research.
When the BOOS module is 'called' by CCP, it will execute the
required program or programs internally. If, however, during the
execution of such a program, access to external data is required,
BOOS will in turn 'call' the BIOS module.
The B lOS module controls and communicates with, all hardware:
the keyboard, the visual display, the disk drives and, via the input/
output ports, all system peripherals. BIOS also controls an area of
dynamic RAM reserved for system data; storing data retrieved from
diskettes and supplying BOOS with the relevant data on request.
5.3 TRANSIENT PROGRAM AREA (TPA)
When any diskette-based program is to be executed or edited, it is
first loaded into the TPA. This is an area of dynamic RAM which is
reserved for user programs and data; its size being proportional to
the total capacity of the system's dynamic RAM.
5.4 DISK DRIVE SELECTION
The left-hand disk drive on all M-THREE systems is always
designated 'A' whilst the right-hand drive will be 'B' if it is a 'Floppy'
drive (either 5 1/4" or
8"1,
or 'C' if it is a Winchester drive (either
5M byte or 10M byte).
When an M-THREE system is first switched on, drive A (the left-
hand drive) will automatically be selected and therefore the prompt
5-2