|Ken Novak's Weblog
Purpose of this blog: to retain annotated bookmarks for my future reference, and to offer others my filter technology and other news. Note that this blog is categorized. Use the category links to find items that match your interests.
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Ken Novak's Weblog
Saturday, September 30, 2006
Windows XP Multiuser Remote Desktop:
With a couple file renames and a registry change, XP can run three remote desktop sessions (normal desktop plus 2 more).
Combined with the $20-30 terminals that are available from outlets like www.surpluscomputers.com, and the $150-250 LCD screens, you can extend an ordinary PC to multiple users (with very low power and zero noise to boot). 9:55:29 PM
Friday, September 15, 2006
SSH for Java:
Lots of implementations of SSH clients in Java, under proprietary, GPL, or BSD lisences. 11:57:48 PM
Lithium buckyballs to store hydrogen?
: Roland Piquepaille provides a perfect example of how nanoscale technology differs develops, going from a realworld problem through computer models to reality. "The clusters they've designed -- by using computer modeling -- are composed of 12 lithium atoms and 60 carbon atoms, are very stable and can store up to 120 hydrogen atoms in molecular form. .. But why did the researchers choose to study this particular kind of material to store hydrogen?
There are two classes of materials: one where large amounts of hydrogen can be stored, but it is difficult for hydrogen to desorb (e.g., CH4), and the other where hydrogen can desorb easily, but not much of it can be stored (e.g., carbon nanotubes). An ideal storage system would be one where hydrogen binds molecularly but with a binding energy that is intermediate between the physisorbed and chemisorbed state. We show that coating of C60 fullerenes with suitable metal atoms may lead to the synthesis of novel hydrogen storage materials. In particular, we show that the unusual ability of Li12C60 to bind 60 hydrogen molecules stems from the unique chemistry at the nanoscale."
It's still a long way from this technology to the pollution-free fuel cell in your car; but model-driven nanotech gives us tools to systematically aproach our targets for technological development. 11:44:05 PM
Wind Blade Technology
: I started looking into sustainable energy in 2001, and found an active community that was open to sharing its findings and that was starting to use the internet to communicate. As I learned about RSS and weblogs, I thought that this area, like many in the IT world, would see weblogs grow, and with them a spontaneous division of labor to speed the spread of new developments would emerge. Blogs from universities, corporations, development institutions, non-profits, and from motivated independents would identify and highlight findings that mattered in specialized areas, and others who would otherwise search original sources would save time and effort by reading their blogs.
In the last 12 months, that dynamic has taken hold in sustainable energy. Starting in 2001, I kept a blog collecting important results I discovered in emerging energy technologies
and developing country energy
options, but now I find others are keeping close track and I can just follow their investigations. They include venture capitalists
, investment companies
, and independent engineers
The Wind Blade blog (above) from six employees of Owens-Corning is an advanced example. They work in different countries, but all concentrate on the materials from which the blades of wind turbines are built. They write: "We accept the value of renewable wind energy as a given and we are
committed to helping it become more cost competitive and widely used." They work in a specialized but critical technology. Why? Well, the output of a wind turbine is proportional to the area swept by its blades, which is the square of the length, so even small increases in blade length matter. Longer blades need materials that are strong, light, and rigid enough to turn in moderate winds while flexible enough to bend rather than break in strong winds. New materials for blades continue to make wind power more economically compelling every year.
It will be interesting to see if these bloggers find an audience among other engineers, and if they retain their corporate backing. 11:21:18 PM
Tuesday, September 12, 2006
: Grameen Foundation USA is sponsoring teh open-source development of an ambitious system for microfinance management. "Mifos is a universal, flexible and scalable software platform for information management for the global microfinance community. Microfinance Institutions (MFIs) will use Mifos as their base operational software to administer their client accounts and financial portfolio. Loan officers will use it to create loans as well as savings, insurance and other financial services. Mifos will be used to record all transactions. It will manage the user and client database, define the products, and create reports for internal use and outside reporting to regulators, funders and supporters. Finally, it will include surveys to help measure the social impact of the MFI operation." 6:13:57 PM
VDI Server Sizing and Scaling
: VMware white paper on the capacity of its latest software to host multiple desktops. "We looked into two different workloads for capacity planning guidelines. For a light worker workload an HP DL 385 G1 server could support 42 Windows XP virtual machines. For a heavy worker workload the same server supported 26 Windows XP virtual machines... [The] server considered to be at capacity when the client fails either due to a 10 percent increase in the canary time observed for the workload or when a client script fails due to predefined timeouts." This was at approx 70% CPU utilization.
"Hardware Configuration for Server Running Desktops: One HP ProLiant DL385 G1. Two 2.2GHz AMD Opteron dual-core processors, 16GB RAM, 2 Ultra 320 SCSI drives (2 × 146GB disks, 15,000 rpm)"
As expected, powering a VM on takes more CPU than un-suspending it. Buth there's another option: you can "power on approximately the number of desktop virtual machines you estimate the host can support, with the virtual machines configured to go into standby mode after a certain fixed interval. ESX Server 3.0 introduces new power management options [e.g.] Windows XP desktops are configured to Wake on LAN .. When any network traffic arrives for a virtual machine, it seamlessly wakes up from standby mode. .. Compared to the resume from suspended state or cold reset option, this activation scheme offers very fast activation (on the order of a few seconds).." 6:10:35 PM
Sunday, September 03, 2006
Linksys courts Linux hackers with WRT54G"L"
: The ubiquitous Linksys wifi router is now manufactured with a non-Linux O/S (Vxworks) with half the flash and RAM. The "new" linux version is the unmodified old one, that has been modified
for new features. Some instructions
tell how to route from wireless to wired (though I think the latest WRT's may do that without modification just by using their non-gateway router mode). 10:09:28 PM
Powerline Ethernet Adapters:
Current (Sept 06) situation appears that residential powerline standard is around 14 mbps, but that different vendors extend it up to 200 mbps max. Carrying HD signals at 28 mbps is an important threshold, with conventional digital video of 20 mbps also important. Netgear does well, as does Zyxel.
Both are $100-120 per adaptor. Linksys has older models at 14 mbps only selling for $65 per adaptor or used down to $30. Both Linksys and Zyxel have adaptors for USB at about the same price as Ethernet. 9:59:39 PM