Timothy
Parker Consulting Incorporated
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Comtrol RocketPort Plus Comtrol is well-known for its multiport
serial systems, and several years ago we reviewed its excellent RocketModem and
RocketPort systems for UNIX. Porting
these boards to Linux is a natural step. The RocketPort Plus lineup has several
configurations, including a two-port model that we tested.
The RocketPort Plus is designed to offer multiple high-speed RS232 ports
that can be configured as any COM device. The RocketPort Plus package we received
included the board, a CD-ROM with software and documentation (the software is
for several operating systems), an updated Linux driver on diskette, and a
three-page installation and configuration procedure. More complete documentation
must be accessed off the CD-ROM, but most administrators and users will be able
to install the RocketPort Plus with the simple instructions provided on the
printed sheets. A neat feature of the Comtrol boards are that they are surge and
static protected at the port interface, protecting the system they are installed
in. Physically, the RocketPort Plus is a normal-sized PCI card with two male DB9
RS232 ports on the back plane. The board chip density is low, using two ASICs
(using 44MHz processors) for the port control. The package also includes a
loopback connector to allow testing of the ports. Installation of the RocketPort
Plus is simple: install the hardware in any available PCI slot, then load the
driver from either the supplied floppy or from an update on the Comtrol Web
site, and run an install make script. In some cases you may have to recompile
the Comtrol RocketPort Plus drivers, but we didn’t have to on our test
systems. You next need to tell Linux to load the
drivers for the RocketPort Plus when booting. This will not be necessary for all
versions of Linux: both RedHat and Debian Linux (in fact any system using the
System V init file setup) can handle the configuration automatically. For
non-System V systems, a simple edit of the /etc/rc.d/rc.S file takes care of the
process. The PCI board installation requires a manual edit of a RocketPort Plus
configuration script to remove ISA/EISA board configuration information. The
gettys for the ports can be set automatically or manually by using inittab. The
entire installation and configuration option took us an average of ten minutes. To achieve baud rates higher than 38,400
the ports have to be remapped. A utility supplied with the RocketPort Plus
allows port speeds of 57,600 (ideal for external V.90 modems), 115,200 (good for
ISDN modems), and a maximum speed of 921kbps. The complexity of remapping the
baud rates depends on the currency of your Linux system.
If it has the most recent version of libc, remapping the ports doesn’t
require the RocketPort Plus utility at all.
Older Linux libc versions require a little more effort, but the end
result is the same. We tested the RocketPort Plus in three
different systems: RedHat 6.2, SuSe 7.1, and Caldera OpenLinux 2.4 (an older
release used as one of our application servers). In all three cases the RocketPort Plus installed and
configured easily, and worked flawlessly. We
tried several external devices connected to the two ports, ranging from modems
(both V.90 and ISDN) through to high-speed serial color laser printers and a POS
(point-of-sale) terminal. Configuring
the different speeds using inittab is simple, or you can simply edit the getty
files yourself. We tested both
ports set to the speed of 230,400 baud, leading to two test PCs configured as X
terminals. With both ports driven
using animation scripts, the RocketPort Plus handled the traffic with aplomb,
giving an average sustained throughput just below 200,000 baud.
We didn’t benchmark the board to the claimed maximum speed of 921kbps
because we couldn’t generate a reliable measurement at these speeds. As with most multiport serial devices,
there’s little glamour in these devices.
They just work, fast, and easily. As
with every other Comtrol device we’ve tested, the RocketPort Plus performs as
expected. If you need two (or more)
configurable fast serial ports, this is an excellent device. RocketPort Plus 2-port PCI Summary: If 921kbps isn’t fast enough for your serial ports, we don’t know where you should turn. Superfast, surge-protected serial ports for your Linux system make this board a winner. |
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Send mail to
tparker@tpci.com with
questions or comments about this web site.
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