9-2 9845B/C Mainframe Diagrams
Memory Map
98458/C
Memory Architecture
Each address
is
a 16 bit word
(2
bytes).
Blocks have 32k addresses, or 64k bytes.
Some
blocks
don't
use
all32k
addresses.
Even blocks (and 1) are
RWM.
Odd
blocks (except
1)
are
ROM.
Here's how this memory map
is
laid out;
Down the left column:
Block numbers (octal)
and
the assembly the memory
is
in.
If the memory
is
standard, an
S;
if
optional, an
O.
Across the top:
Addresses (octal)
is
lOk/20k ranges across the top.
Data in the map:
The information
in
that block/address range of memory. If
ROM,
it's processor, use
and
option
ROM
product number.
(N)
Numbers
in
parentheses refer to notes at the
end
of the map. Empty areas either
don't
exist or are not presently used.
A complete list of system
and
option
ROMs,
with revisions and part numbers
is
available by
listing on the printer, the 9845B/C System Exerciser Tape
#2,
the
ROMREV
file
starting with
line
5190.
Notes
(shown in parentheses in memory map)
1.
Addresses 0-37
in
each block are common processor addresses.
RWM
and
ROM
use
addresses
000040-177777.
2.
This location
is
ROM
for
CRT graphics.
See
parts
list
for
details.
3. More CRT
ROM,
the parts
list
shows specifics.
4. These are the keyboard language
ROMs,
six
sets exist
for
six languages. Refer to parts
list
for specifics.
5.
Two optional graphics
ROMs
are available,
98411A, for the standard CRT, addresses
030000-047777.
98411B, for enhanced and/or color CRT, addresses 030000-067777.
Special Note on Block 0
RWM
Allocations:
Block 0 contains the following
map
at
execution time,
If no A26 optional
RWM
assemblies are installed,
Address 177777 Block
DeSCriptor
System
RWM
LPU
System
RWM
Option
ROM
RWM
Binary Programs Area
Execution Stack
Buffer Space
Program Segments
Value Area
COM System Common
lCOM Assembly Common
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