On September 28, 2021, I asked on Twitter:
PL Twitter:
you get to recommend one published PL paper for an undergrad to read with oversight by someone experienced. the paper should be interesting, approachable, and (mostly) self-contained.
what paper do you recommend?
TraceEvent can cause OOMs in simulation #2218
I recently happened upon a very interesting implementation of popen() (different API, same idea) called popen-noshell using clone(2), and so I opened an issue requesting use of vfork(2) or posix_spawn() for portability. It turns out that on Linux there's an important advantage to using clone(2). I think I should capture the things I wrote there in a better place. A gist, a blog, whatever.
This is not a paper. I assume reader familiarity with
fork()in particular and Unix in general, though, of course, I link to relevant wiki pages, so if the unfamiliar reader is willing to go down the rabbit hole, they should be able to come ou
Disclaimer: This piece is written anonymously. The names of a few particular companies are mentioned, but as common examples only.
This is a short write-up on things that I wish I'd known and considered before joining a private company (aka startup, aka unicorn in some cases). I'm not trying to make the case that you should never join a private company, but the power imbalance between founder and employee is extreme, and that potential candidates would
State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?
There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.
Here I present a composable pattern for pure state machiness with effects,
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
Movies Recommendation:
Music Recommendation:
| #!/usr/bin/env python | |
| import boto | |
| from boto.route53.record import ResourceRecordSets | |
| import logging | |
| conn = boto.connect_ec2() | |
| DNS_EXCLUSION_TAG = 'ExcludeFromDNS' # If this tag exists on an instance, no DNS values will be populated | |
| DNS_TAGS = ['ShortName', 'Name'] # This is the list of instance tags we want to populate DNS entries from | |
| DNS_SUFFIX = 'YOUR_SUBDOMAIN_HERE' # Suffix under which to create DNS records | |
| ROUTE53_ZONE_ID = 'YOUR_ZONE_ID_HERE' # The zone id from route53 of the zone we will be adding these entries under |
