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It should also be noted that only 8 colors are displayed on the 5279 and the
5379 when emulating the adapter.
IBM PC DOS 2.1 Limitations
Applications using the IBM PC DOS 2.1 must not:
1.
Use interrupt vectors X'50' through X'57'.
2.
Reprogram the 8259 Interrupt Controller.
3.
Access storage addresses above the interrupt-level-12 pointer in BIOS
(basic input/output system) except to reference the IBM Personal
Computer display refresh buffer.
4.
Disable interrupts, fail to issue an End-of-Interrupt or IRET on a
hardware interrupt level, or mask selected interrupt levels for more
than 100 ms.
5.
Issue instructions to an IBM Personal Computer display adapter 6845
CRT Controller.
6.
Use IBM PC DOS 2.1 print spooling.
7.
Depend for successful operation on receiving control within a fixed
amount of time after an interrupt.
Such timing problems can occur if, for example, the application is to be
used at the same time as graphics processing in the work station.
3270-PC Work Stations using the IBM 5272 Color Display
Most applications that run on IBM 5272 work stations will run on the 5279
and the 5379 work stations provided equivalent hardware features and
sufficient storage are available but account must be taken of the following
differences:
•
The IBM 5279 and 5379 work stations emulate only the Color/Graphics
Monitor Adapter of the IBM PC. On IBM 5272 work stations the
Monochrome Display Adapter is also emulated.
•
On the IBM 5272 work station host graphics is achieved using three
triple plane and three single plane programmed symbol sets. On IBM
5279 and IBM 5379 work stations vector graphics are used. As with the
IBM 3279, GDDM applications should migrate by using GDDM Release
4.
Appendix
B.
Compatibility Considerations
101
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