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Kragen’s followup to Dercuano:
a book of notes on various topics, mostly science and engineering with some math, from the first year of the COVID-19 pandemic, 02020 CE. Its primary published form is a gzipped tarball of 9MB of HTML files and sources, although there’s also an inferior PDF version of about 1000 pages for reading on hand computers or printing. It uses a page size slightly smaller than standard for improved readability on hand computers. [….] It contains some novel discoveries, but some of it is just my notes from exploring the enormous feast of knowledge now available on the internet to anyone who takes the time to taste of it, and some other parts are explorations that didn’t pan out — left here only as a cautionary tale to the next explorer. There are lots of notes in here that aren’t “finished” in the usual sense; they end in the middle of a sentence, or say “XXX”, or have a note in them that the foregoing is wrong in such-and-such a way. But I am publishing the final version of Derctuo today. I might make future versions of some of these notes, but not of Derctuo itself.
A large scale analysis of hundreds of in-memory cache clusters at Twitter | USENIX
Modern web services use in-memory caching extensively to increase throughput and reduce latency. There have been several workload analyses of production systems that have fueled research in improving the effectiveness of in-memory caching systems. However, the coverage is still sparse considering the wide spectrum of industrial cache use cases. In this work, we significantly further the understanding of real-world cache workloads by collecting production traces from 153 in-memory cache clusters at Twitter, sifting through over 80 TB of data, and sometimes interpreting the workloads in the context of the business logic behind them. We perform a comprehensive analysis to characterize cache workloads based on traffic pattern, time-to-live (TTL), popularity distribution, and size distribution. A fine-grained view of different workloads uncover the diversity of use cases: many are far more write-heavy or more skewed than previously shown and some display unique temporal patterns. We also observe that TTL is an important and sometimes defining parameter of cache working sets. Our simulations show that ideal replacement strategy in production caches can be surprising, for example, FIFO works the best for a large number of workloads.
(tags: caching memcached memory twitter usenix via:marc-brooker)
Is there a tool that tells you which IAM actions to allow if you give it an API operation? : aws
‘For example, say I want to allow an IAM role to aws s3 sync to a given S3 bucket. Is there a tool that will tell me the list of actions to permit on the bucket, if I input that command to the tool?’ tl;dr: nope there is not. Good list of links to related tools to ameliorate the IAM shitfest though
(tags: iam aws permissions security apis)
The PHIA probability yardstick
the UK government’s official terminology to clearly describe the probability of events occurring, ranging from “REMOTE CHANCE” to “ALMOST CERTAIN”
(tags: chance probability terminology words uk phia odds)
Mason, Thomas Holmes (1877-1958)
My illustrious great-grandfather:
Mason was a keen cyclist; his tours through the Irish countryside as a youth, as well as his interest in photography from the age of twelve (he would take over 20,000 pictures by his death), led him to the study of the natural world and Irish archaeology. This culminated in his publication of The islands of Ireland: their scenery, people, life and antiquities (1936), visually recording the minutiae of Irish folk life and the natural beauty of the island landscapes. Mason did not restrict his interests to any one discipline and was involved in a multifarious range of organisations: member of the Dublin Field Club, one-time president of the Irish Society for the Protection of Birds, member of the Dublin Zoological Council (serving as honorary vice-president from 1952), member and president (1926) of the Photography Society of Ireland, member of the Geographical Society of Ireland, and member of the National Monuments Council as well as president (1951) of An Taisce. He was also president of the Dublin Mercantile Association (1923) and the Dublin Rotary Club and a fellow of the RSAI. He was elected MRIA (1931) and contributed numerous articles to the Academy’s Transactions and Proceedings on subjects ranging from the history of the optical profession in Dublin to Celtic archaeology. Mason provided meteorological information to Irish newspapers from his home observatory at 39 Kenilworth Square before the establishment of the Irish meteorological service (1936). His other interests included Irish moths as well as Irish lantern slides, on which he published Catalogue of photographic lantern slides of Irish scenery and antiquities [n.d.] and Catalogue of lantern slides of Irish antiquities (1928). Mason was the seventh member of his family to be made an honorary freeman of the city of Dublin (29 April 1903), one of the last such hereditary appointments. His wife Margaret Evelyn, whom he married c.1909, was a fellow presbyterian. Three of his four sons succeeded him in the family business, which celebrated its bicentenary in 1980 and traded into the third millennium. He died on 12 February 1958, leaving his library to the Old Dublin Society and TCD.
(tags: family thomas-mason history ireland archaeology photography)
