http://www.opennet.ru/openforum/vsluhforumID3/65661.html#23 Notes (exert) from Joanna Rutkowska recent paper comparing KVN and XEN architectures from security and design standpoint
http://varnish-cache.org/wiki/ArchitectNotes excellent notes about app design, and what can happen if an app tries to implement its own memory management
http://wiki.secondlife.com/wiki/Message_Queue_Evaluation_Notes Second Life notes about Message Queue Systems
http://mjg59.livejournal.com/117532.html article by Matthew Garrett that actually explains how ACPI works
http://highscalability.com/blog/2009/10/26/facebooks-memcached-multiget-hole-more-machines-more-capacit.html also see http://dormando.livejournal.com/521163.html Describing some problems with performance/scalability you may have if you partition/shard your data by hash. ( that’s what memcached does.) You may hit the cpu bound limit from the amount of requests that few very popular keys receive. Currently, there is now common way around this (perhaps because very very few sites scale to the point when this becomes an issue )
http://www.sdsqlug.org/presentations/May2009/MySpace_DB_Overview.pptx myspace architecture presentation, talks about how to myspace solves its database issues
http://blog.zhuzhaoyuan.com/2009/09/nginx-internals-slides-video/ very good presentation slides explaining nginx internals, such as main architecture, main event loops, core modules, processing pipelines, etc. Also there is a video of the talk , but it is mandarin, so YMMV :-)
http://highscalability.com/yahoo-s-pnuts-database-too-hot-too-cold-or-just-right writeup on yahoo PTUNS (distributed database ). Also, see the original paper if you are interested.
http://lwn.net/Articles/321702/ Message to Kernel Mailing List about differences between XEN and KVM .
http://duartes.org/gustavo/blog/post/memory-translation-and-segmentation very goom sum-up about memory mechanism in modern x86 machines. For more elabored and detailed info