|Headquarters||Kirkland, Washington, U.S.A|
|Len Bosack and Sandra Lerner|
|Products||Darkstar Optical Network Hardware|
XKL, LLC, was founded in 1991 and develops optical transport technologies. Originally based in Redmond, Washington its headquarters are now located in Kirkland, Washington. XKL is led by Cisco Systems co-founder Len Bosack who also used to work for DEC and Bell Labs. Under Bosack, Cisco commercialized local area network (LAN) technology to connect geographically to computers over a multiprotocol router system.
History of XKL
In its earliest days, XKL built a compact, modern replacement (TOAD-1) for a massive mainframe computer system (PDP-10) that had gone out of production. The challenge at the time was to find a mainstream usage for a totally new technology: a platform with a desktop-sized footprint, but incorporating technology that would bring the system into the 21st century.
XKL deployed DarkStar technology that allows enterprises to take advantage of higher reliability and allow for more control over IT resources at a lower cost. The “plug and play” system allow data network engineers to deploy their own optical transmission systems in metro, regional and long distance networks.
The TOAD-1 System, also known as TD-1,[notes 1] was announced in 1993 and built as an extended version of the DECSYSTEM-20 from Digital Equipment Corporation. The original inspiration was to build a desktop version of the popular PDP-10 and the name began as an acronym for "Ten On A Desk". It was eventually built at XKL by veteran engineers from Cisco, DEC, Hewlett-Packard, and CDC.
It was the first XKL product produced and it became available for purchase in late 1995. The TOAD-1 is a high-performance I/O oriented system with a 36-bit processor running TOPS-20. It is a 36-bit multi- user system that can provide service to over 100 users at a time. The TOAD-1 architecture incorporated modern peripherals, and open bus architecture, expanded physical and virtual memory while maintaining the TOPS-20 user environment.
The TOAD-2 was built to replace the TOAD-1 and was a single chip reimplementation, used as redundant control processors in networking equipment from XKL. It could be configured for TOPS-20 timesharing.
First released in 2007, XKL installed the Darkstar DXM at the California Institute of Technology as part of their Supercomputing Bandwidth Challenge. It provided 5 times the bandwidth, in excess of 100 Gigabits/sec, than the existing system but was also smaller and used less power. 
- The TOAD-1 was referred to as the TOAD as a development codename and then changed to the TD-1 as the original marketing name. It was then swtiched back to TOAD-1 before production began.
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- Duffy, Jim. "Cisco founder wants to go faster, farther". Network World. Retrieved 2009-06-01.
- "Len Bosack and XKL introduce "Do It Yourself Optical Networking"". GLG Group. Retrieved 2007-08-08.
- "Cisco Founder Pushes for DIY Optical Networks". Light Reading. Retrieved 2009-07-03.
- "Len Bosack speaks with Erik Linask at ITEXPO". TMCNet. Retrieved 2010-10-06.