SteveJ-restore-test

Two new things appeared in my world recently: A friend showed me Google 'Jump Desktop' , connecting his iPad to his Desktop. [Apple have their own 'Remote Desktop' product which I haven't researched. Not sure if it works over the wider Internet as well.] Joe Wilcox's piece (Jan-2011) on Apple dumping desktops sometime (soon) as they become less relevant. Wilcox wonders what will happen to "Power Users" if Apple move on Desktops, as they've moved on from the rack-mount X-serve line. Customers needing servers now have the choice of a Mac Mini Server or a "Mac Pro" (tower). Can Apple afford to cut-adrift and ignore the needs of good folk who rely on their product for their business/livelihood, some of whom may have used Macs for 20+ years?? Would seem a Bad Idea to alienate such core and influential users. Clearly Apple look to the future, and like the floppy drive they expunged long ago in favour of Optical drives (now also obsolete), Des...

Summary : For the delivery of general purpose and wide-scale Compute/Internet Services there now seems to be a definitive hardware organisation for servers, typified by the E-bay "pod" contract . For decades there have been well documented "Design Rules" for producing Silicon devices using specific technologies/fabrication techniques. This is an attempt to capture some rules for current server farms. [ Update 06-Nov-11 : "Design Rules" are important: Patterson in a Sept. 1995 Scientific American article notes that the adoption of a quantitative design approach in the 1980's led to an improvement in microprocessor speedup from 35%pa to 55%pa. After a decade, processors were 3 times faster than forecast.] Commodity Servers have exactly three possible CPU configurations, based on "scale-up" factors: single CPU, with no coupling/coherency between App instances. e.g. pure static web-server. dual CPU, with moderate coupling/coherency. e.g. web-s...

The 7 Millennium Prize Problems don't resonate for me... These are the areas that do engage me: Datacentre Hardware organisation , power, cooling and interconnect fabric Multi-level memory and impact on Operating Systems. Flash as RAM, disk cache or SSD? Flexible Hardware and supporting Systems and Software Internetworking protocols . IPv4 isn't secure, IPv6 is overblown. The piece for the second item, "Multi-level memory" is old and not specifically written for this set of questions. Expect it to be updated at some time.

Related posts: Everything Old is New Again: Cray's CPU design A Good Question: When will Computer Design 'stabilise'? Senior Google staffers wrote The Datacenter as a Computer: An Introduction to the Design of Warehouse-Scale Machines, which I thought showed break-through thinking. The importance of this piece is it wasn't theoretical, but a report of What Works in practice, particularly at 'scale'. Anything that Google, one of the star performers of the Internet Revolution, does differently is worthy of close examination.  What do they know that the rest of us don't get? While the book is an extra-ordinary blueprint, I couldn't but help asking a few questions: Why do they stick with generic-design 1RU servers when they buy enough for custom designs? How could 19-inch racks, designed for mechanical telephone exchanges a century ago, still be a good, let alone best, packaging choice when you build Wharehouse sized datacentres? Telecommunications sites use...

I found myself writing, during a commentary on the evolution of SSD's in servers , that  large-slow-memory like Seymour Cray used (not cache), would affect the design of Operating Systems. The new scheduling paradigm: Allocate a thread to a core, let it run until it finishes and waits for (network) input, or it needs to read/write to the network. This leads into how Seymour Cray dealt with Multi-Processing, he used multi-level CPU's: There were Application processors, many bits, many complex features like Floating Point and other fancy stuff, but had no kernel mode features or access to protected regions of hardware or memory, and Peripheral Processors (PP's), really a single very simple, very high-speed processor, multiplexed to look like 10 small, slower processors that performed all kernel functions and controlled the operation of the Application Processors (AP's) Not only did this organisation result in very fast systems (Cray's designs were the fastest in t...