darrenldl

#lang racket

(require megaparsack megaparsack/text)

(module+ main
  (displayln
   (with-handlers ([exn:fail:read:megaparsack? (λ(x) #f)])
     (parse-result!
      (parse-string integer/p "123"))))
  )

darrenldl

standard-module-name-resolver: collection not found
  for module path: racket/match/gen-match
  collection: "racket/match"
  in collection directories:
  context...:
   show-collection-err
   standard-module-name-resolver
   #%embedded:g2732:curly-fn-transformer: [running expand-time body]
   get-sym
   /usr/share/racket/collects/racket/promise.rkt:58:10

darrenldl

Achieving warp speed with Rust

Contents:

• Number one optimization tip: don't
• Never optimize blindly
• Don't bother optimizing one-time costs
• Improve your algorithms
• CPU architecture primer
• Keep as much as possible in cache
• Keep as much as possible in registers

darrenldl

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  ms/call  ms/call  name    
 74.00     10.93    10.93                             camlReed_solomon_erasure__Galois__mul_slice_xor_pure_ocaml_inner_5708
 14.22     13.03     2.10 1900021475     0.00     0.00  camlPervasives__char_of_int_1125
  4.60     13.71     0.68      345     1.97     1.97  camlPervasives__$5e_1117
  4.13     14.32     0.61                             camlReed_solomon_erasure__Galois__mul_slice_pure_ocaml_inner_5701
  1.49     14.54     0.22 12582912     0.00     0.00  camlRandom__intaux_1238

darrenldl

let swap (a : int array) (i : int) (j : int) : unit =
  let temp = a.(i) in
  a.(i) <- a.(j);
  a.(j) <- temp

(* Took a while to understand what you're trying to do in this function,
 * add comments in future whenever you have a non-trivial piece of code *)
let small_to_front (arr : int array) (start_unsorted : int) : unit =
  (* W.r.t aux, see below *)
  let rec aux (arr : int array) (start_unsorted : int) (i : int) (index_smallest : int) : unit =

darrenldl

3.0.6
http://get.videolan.org/vlc/3.0.6/vlc-3.0.6.tar.xz
VideoLAN and the VLC development team present VLC 3.0.6 "Vetinari".
VLC 3.0.6 is a minor update to VLC 3.0 branch, improving hardware decoding, Windows 10 and macOS mojave integration, RTSP, Bluray but also adding the support for a fast AV1 decoding.

darrenldl

Ubuntu LUKS keyfile guide

Goal

We want to be able to set up an encrypted Ubuntu installation where we can unlock using just an external USB key without entering any passwords

We do not consider evil maid attacks in this case, and are only worried about data leak

We also assume USB key is kept securely, thus we are not concerned with USB key not being encrypted

darrenldl

Cornell CS3110 2019 Chapter 8.2 Streams thought process

Context

This is a document in response to a Discord question on how to go about understanding the definition of nats in the chapter listed in title.

We cannot teach intuition, but giving one a more indepth view on how someone else thinks might allow one to draw inspirations and form intuitions more efficiently than just staring at a (very) abstract object for days.

Following documents some of the ways I dissected/thought about nats, as an attempt of achieving the above goal.

darrenldl

Articles

• https://beepb00p.xyz/scheduler.html

Existing schedulers

• https://github.com/leahneukirchen/snooze
• https://github.com/systemd-cron/systemd-cron
• https://ohse.de/uwe/uschedule/intro.html
• https://github.com/karlicoss/dron
• https://code.dogmap.org./runwhen/

darrenldl

Proof of attack vs proof of security

Soundness (NO false positives, may false negatives)
- May miss out legitimate cases
- "Conservative" systems normally at least have soundness
Completeness (may false positives, NO false negatives)
- Never miss out legitimate cases, but may grab more than needed

Proof of attack (off sec)
- Under some premises, shows there exists an attack for a given system (e.g. protocol, software)