Vector 4 - Page 62

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VECTOR 4
TECHNICAL INFORMATION
This program initializes the ports, executes several testing routines and
sends the booting menu to the CRT. The testing routines consist of:
-~ Memory Test
- PROM Checksum Test
- Keyboard 1I/O Test
If any of these tests fail a prompt indicating the error will be displayed.
These prompts are discussed in Part III: Tests and Adjustments.
The user selects the type of disk which is going to be used for the
booting process.
That specific booting program is initiated which causes the system tracks
to be loaded into the system memory map at 01000H ("Global Address").
The following list gives the number of system tracks used by each disk. *
Disk | Number of System
Tracks
9 1/4 inch Floppy 4
5 1/4 inch Hard Disk 2
The newly loaded program located at 01000H ("Global Address") now loads
in the rest of the CP/M file into the RAM. This results in the PROM
being disabled (Through Port 02H) and the CP/M system block beginning at
00000H and ending at 1FFFFH.
When a users program (physically located within top 58 K bloeck of RAM) is
run it is re-mapped logically (in 2 K segments) to the lower 58 K block.
During this time the operating system is located in the background. This
occurs because the Z80B can only address from 0000H to FFFFH. If the
Vector 4 is running with the 8088-2 microprocessor, which has 18 address
lines connected, then the "Global Address" is always used (NOTE: This
would require a different operating system).
Refer to the VECTOR 4 PROGRAMMERS GUIDE for a complete explanation of
the booting process.
09-01-82
7200-0001 I1 2-19