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The History of
KVM Over IP Switches, Hybrids and Appliances
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The concept of remote control of computers is nothing new. It has been
available via software-only products for over a decade, and
continues to be popular for some functions. Products like PC
Anywhere, Carbon Copy, Timbuktu and so forth are examples of these software
programs. The drawback to all software-only remote access is that it
requires the computer being accessed to be running and functioning
properly. This is almost useless for serious system maintenance
since a computer that's running properly doesn't need
emergency-access maintenance, and one that isn't won't respond to
the remote client software. That's one of the primary reasons for
acquiring a digital keyboard, video and mouse switch (dKVM) product.
With dKVM, you can diagnose and remedy problems from afar (whether
that's 50 feet, 50 miles, or 5,000 miles), including the entire boot
sequence. Try intercepting the CMOS and instructing it to ignore the
floppy disk inadvertently left in the A drive after you manage to
send a CTRL-ALT-DEL command with your software-only remote product,
and you'll immediately lust for a dKVM solution.
The
fist dKVM appliance was really a dKV system (no mouse support), and
was designed and manufactured in the mid 1990's by Fox
Network Systems. Their Keyview™
supported gray-scale VGA video and did permit secure, remote access
via a LAN/WAN or dialup connection. A few years later, Apex,
the largest seller of KVM switches (who are now part of Avocent)
introduced their Emerge, the first true dKVM appliance. It did
support mice... and color, too. Fox's Keyview was subsequently
acquired by Cybex (now also part of Avocent) and Cybex completely
revamped it to become the Keyview II
in the late 1990's. Both the Emerge and the Keyview II functioned
similarly. They were Windows NT-based computers with special PCI
cards and software installed. Emerge used
Carbon Copy™, and Keyview used PC Anywhere™, as means to
provide remote access. However, instead of merely using those
software products to control the Emerge or Keyview computer (which
was possible), the special cards and wrap-around software permitted
keystrokes and mouse action to pass out through additional PS2 mouse
and keyboard ports, where they could then control a single computer
or an analog KVM switch. Similarly, the video from that
"target" computer or switch came back into a VGA port on
the Emerge or Keyview, where it was digitized and sent back to the
person accessing the dKVM appliance. Emerge was upgraded to
Emerge II, with improved performance, but both systems were
relatively awkward to set up (Keyview was a bit more difficult), and
both were relatively slow to respond. That is, there were
significant lags in screen repainting and in mouse tracking. Still,
they beat a drive across town in the middle of the night to fix a
hung server. They were also fairly pricey, at $5,000 to $6,000 list
price for one path to one device. And because they relied upon
off-the-shelf remote access software and the limited power of
then-available frame grabbers, they weren't very good at digitizing
the video and sending a clean signal quickly. Mostly, they were for
emergency maintenance access, and they did a fair job of that...
especially considering the lack of alternatives.
The First dKVM Switch
turned a major leaf in this saga in 2000 with the introduction of
their DS1800 switch. Melding
analog technology from their existing KVM switches (Autoview 400
series) and digital video technology from their acquisition of
Pixelvision, Avocent delivered a product that was fundamentally
different from and better than the earlier dKVM appliances. First,
it was a switch, with 8 ports for connection directly to servers (or
to other analog switches). Second, it could handle 8 simultaneous
access paths to those 8 ports, which means that 8 different people
could use the device to look at and control different devices all at
once. With a base price tag at the time of $10,000 (plus at least
$2500 for software and CPU-to-Switch cables), it wasn't cheap, but
it was less than the cost of TWO of the previous dKVM appliances and
did more than the work of 8 of them. More importantly, the DS1800
was faster, did much better with the video and, in subsequent
revisions (requiring only a flash firmware and software update),
proved to be substantially faster over network connections. The
price was reduced about 20% last year, and additional models were
introduced (more on that later). Unlike the older dKVM appliances,
this unit was designed around the premise of high-speed connectivity
and has no modem port (it's possible to hang a modem on it and make
it work via dialup, but the manufacturer doesn't explicitly support
that nor would performance be stellar with a 56 kB/sec line).
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