Performance 5-29
MX2A137REFGD Revision A MX2 Reference Guide
Performance
This section describes issues relating to serial performance on the MX2.
Although these issues are described in the context of XFER, they apply
to serial transfers in general.
File-transfer speed is severely reduced when byte counts are displayed
on the MX2 screen. Use the Q option in XFER to enable quiet mode and
speed up transfers.
Performance also is diminished when data is transferred to the C drive or
to a PCMCIA ATA card. Both of these devices write data to the disk
very slowly. Problems may arise as the disks become full and loading
algorithms are executed to clean up space for new data. This can become
particularly severe with Zmodem in streaming protocol, because the
sender never waits for the receiver to write data to the disk. To avoid this
problem, use Zmodem with either windowing or flow control enabled.
Flow control is generally faster and permits the receiver to operate at its
peak capacity.
Another factor in performance is the presence of other software running
in the background. Card and socket services, for instance, use the timer
interrupt for certain functions. Because card and socket services chain
into this interrupt and execute some code with interrupts disabled, the
system may become overburdened when running serial interrupts at high
speed (greater than 19200 baud). In this case, overrun, parity, and
framing errors become more common, sometimes resulting in an
inability to send a file efficiently. If this occurs, select a lower baud rate
and enable flow control.
