From 385371f1f8a4ea6430894dd9a2ec9418253afbef Mon Sep 17 00:00:00 2001
From: bnewbold <bnewbold@robocracy.org>
Date: Thu, 5 Jul 2012 11:00:36 -0500
Subject: misc additions

---
 software/debian.page   |  2 ++
 software/misc.page     | 25 +++++++++++++++++++++++++
 software/packages.page |  1 +
 3 files changed, 28 insertions(+)

(limited to 'software')

diff --git a/software/debian.page b/software/debian.page
index 16d456d..ba49a33 100644
--- a/software/debian.page
+++ b/software/debian.page
@@ -50,6 +50,8 @@ Some gotchas from installing debian a few times:
  * To install emacs without an X environment, use ``emacs23-nox`` (or a more
    recent version).
 
+ * To change time zone: ``sudo dpkg-reconfigure tzdata``
+
 Debian Package Tools
 ------------------------------
 ``dkpg -S somefile`` shows what packages a given file were installed by. ``dpkg
diff --git a/software/misc.page b/software/misc.page
index 8152c92..ecedf85 100644
--- a/software/misc.page
+++ b/software/misc.page
@@ -123,3 +123,28 @@ are invisible within Inkscape but visible when exported.
 To remove this box, edit the raw XML using the XML Editor in Inkscape
 (Shift-Ctrl-X), look for an svg:flowRoot element within the first layer, and
 delete it.
+
+Latency Numbers
+-----------------
+
+From https://gist.github.com/2841832::
+
+    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
+    Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
+    Read 4K randomly from SSD*              150,000   ns    0.15 ms
+    Read 1 MB sequentially from memory      250,000   ns    0.25 ms
+    Round trip within same datacenter       500,000   ns    0.5  ms
+    Read 1 MB sequentially from SSD*      1,000,000   ns    1    ms  4X memory
+    Disk seek                            10,000,000   ns   10    ms  20x datacenter roundtrip
+    Read 1 MB sequentially from disk     20,000,000   ns   20    ms  80x memory, 20X SSD
+    Send packet CA->Netherlands->CA     150,000,000   ns  150    ms
+
+    Notes:
+    1 ns = 10-9 seconds
+    1 ms = 10-3 seconds
+    * Assuming ~1GB/sec SSD
diff --git a/software/packages.page b/software/packages.page
index 99aeeb1..639c056 100644
--- a/software/packages.page
+++ b/software/packages.page
@@ -31,6 +31,7 @@ Almost all machines get the following (decreasing minimalism):
     netcat
     ngrep
     tcpdump
+    mtr
 
 If debian-based, add ``build-essential``, ``openssh-server``, ``manpages-dev``,
 and it's ``git-core`` (not ``git``). See also [debian].
-- 
cgit v1.2.3