Radio Shack TRS-80 Model 16B

APPENDIX D: Specifications
The Radio Shack TRS-80 15-Meg Built-in Hard Disk System is a •
disk-based computer system with two major parts:
• A display console with a Built-in Hard Disk System and a
built-in double-sided, double-density floppy disk drive.
• A detached keyboard which can be positioned for your
comfort and efficiency
The operating system software
is loaded from a system diskette in
Drive ill or Drive 4 by a built-in ROM "bootstrap" program.
Processors
Input/Output Processor System
• Z80-A based with 64K bytes of random access memory
• Independent bus can support all the standard system boards
• Emulation mode lets you execute programs previously
developed for the TRS-80 Model II without changing them first.
Computational Processor System
• 68000 based with either 128K or 256K (384K or 512K bytes on
a Model 168) of RAM
• Independent bus can support multiple bus masters
The two processors share the computing load from the application •
programs (the
Z80-A based processor performs input/output tasks
while the
68000 based processor performs computational tasks),
Video Display
LSI Controller Chip
Frees the input/output (Z80-A based) processor from much of the
overhead required to update and maintain the video display.
Four Modes
• Green/White on black (normal)
• Black on green/white (reversed)
•
80 characters by 24 lines
• 40 characters by 24 lines
Displayable Characters
• Full ASCII set
• 32 graphics characters
•
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