User`s guide

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from and written to the serial device using the UNIX read ( ) and write ( )
system calls.
The UNIX network driver includes a ldv-pos t-events ( ) function that should
be called periodically from the client application in order to assure that the
SLTA-10 Adapter traffic is being processed.
The DOS network driver serial I/O functions are implemented by MSD-SIO . C,
MSD-UART . H, and MSD-IRQC . ASM. These files may all be replaced as long as the
required serial I/O functions in MSD-s IO. c are provided. The definitions of the
UART registers are in MSD-UART . H. The DOS serial I/O interrupt service
routines arein MSD-IRQC.ASM.
The DOS network driver uses the DOS system timer tick interrupt (vector OxlC)
and the serial I/O device interrupt for the relevant COM port to perform
background processing of the serial network interface. The driver hooks into
these interrupt vectors and executes driver code whenever the LON(n) device is
opened. Flags internal to the driver prevent the interrupt code thread from
interfering with the normal application foreground execution of functions within
the driver.
The smip-int-main ( ) function in the DOS network driver services the serial
port connected to the network interface.
The function t ick-int-main ( )
services the timer tick interrupt every 55 msec.
Both network drivers are fully buffered for both outgoing and incoming
messaging. Read and write functions work with circular buffers within the
driver.
The host interrupt service routine handles the other ends of these buffer
queues.
Both network drivers only support a single set of output buffers. An elaboration
on this design could implement a set of priority output buffers.
The write
function could determine into which of the two buffer sets to place messages, and
the driver service function could service the priority buffers first.
Implement and test timer support functions.
Timer support may be provided by
a hardware timer as is done in the DOS network driver, by a system service as is
done in the UNIX network driver, or by implementing a background software
task. The UNIX network driver uses a once per second signal that is handled by
the second-service ( ) function. The DOS timer functions are implemented by
MDV-TIME.CandMDV-T1ME.H.
Implement and test the host side of the network interface protocol. The network
interface protocol is implemented by the rx-process ( ) and tx-process ( )
functions in the UNIX driver, and by the functions in MSD-TXRX . c for the DOS
network driver.
Implement and test raw modem I/O if you need to support a modem interface.
Raw I/O manages the serial interface to the modem when the modem is not
connected to a host and is used for modem initialization and control. The raw I/O
interface is implemented in MSD-RAW. c for the DOS network driver, and is not
implemented in the UNIX network driver.
Implement and test the buffer request states, buffer management, and read/write
interfaces. These functions are implemented by MSD-EXEC . c for the DOS
Creating an SLTA-10 MIP Mode Driver