blockchain – phrasebook

A blockchain is a peer-to-peer network that timestamps records by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work.

In contrast, a distributed ledger is a peer-to-peer network that uses a defined consensus mechanism to prevent modification of an ordered series of time-stamped records. All blockchains are distributed ledgers, but not all distributed ledgers are blockchains.


Peer-to-peer — no central single-point-of-failure
Immutable — records of past transactions
Ever-growing — the chain keeps growing and never shrinks
Double-spend — is a common error to be prevented by blockchain

angular.js jQuery node.js — phrase book

server-side — Node.js is only library designed for server-side use.

web UI — most of the javascript libraries are meant for web UI

cross-browser support — jQuery, Angular

I feel jQuery is more popular than the other javascript libraries.

php-integration? I have seen books dedicated to jQuery+php

DOM — well supported in jQuery

Ajax — well supported in jQuery

data binding — a major feature of Angular.js, not jQuery.

compressed content in a http response

Now I feel an http response may be a zip containing multiple files. The response “body” will be an compressed bytes array. (To avoid confusion, I will call this a “zip” rather than a “file”.) When you parse these bytes, you may see multiple zip entries.

If you assume the entire zip is a single file and try to decompress/deflate it, it might fail. The output may be empty.

The http response also contains useful response headers. One of the headers would be content-type. The gzip and zip types seem to require different parsers.

Fairchild Semicon’s IP traffic priority

Practical insight. Extremely useful to a company economizing on bandwith

Based on packet “protocol” [1], an IP router can give relative priorities to
Priority 1: voip packets
Priority 2: peoplesoft traffic
Priority 3: browser traffic
Proirity 4: lotus notes replication traffic

Lower priority packets are dropped more.

The most important browser traffic is, hold your breath, sales processing[2]. Sales staff use a web interface to process sales data. DB resides on another continent! In a rare but illustrative /incident/, lotus traffic ate into Priority 3 bandwidth and brought sales processing to a grinding slowdown.

As an alternative to a relatively fragile web interface, I suggested async messaging-based sales processing application. No clear answer.

[2] perhaps including but not limited to sales order
[1] packet headers on one layer of the envelopes

3 steps to understand "signing a msg" with a private key

1) understand basic meanings of your private key ^ your pub key.

If you can’t remember anything, remember to keep your private key very
very private, and publish your pub key to friends.

If you can remember one more thing, then remember

“sign with private key; verify with public key”.

2) understand “digsig” — an encryption of a msg, encrypted with your
private key

You often send the digsig to your receipients to certify something.
Receipients can verify your digsig using your pub key

3) understand what it means to “sign a msg”.

In the simplest case, it means “produce a digsig, and send the (cleartext) msg + the digsig”

Q: This process offers CIAn?
A: IAn but not Confidentiality since you actually send a cleartext msg

css selector clearly explained

Q: what's a “selector”, in one sentence of plain english?
A: bit of a CSS definition that says what the styles are applied to

Q: 3 basic types of selectors?
* HTML Elements, such as

tags, tags etc.
* Elements with a specific class, for example an element with the
class “mystyle” (

* Elements with a specific ID, for example an element with the ID
“myparagraph” (


Q: pseudo selectors's signature, purpose, eg?
A: Examples of this are link states (unused, visited, active) and
first lines and letters. The selector has a colon after it with the
state before the definition. An example of this is the CSS definition
for changing the colours of link colours:

A:link {color:blue;}
A:visited {color:green;}
A:active {color:gold;}

Q: nested selector example?

ldap names

In LDAP, the situation is slightly more complicated. Names are built from components that are separated by commas (“,”). Like DNS names, they read from right to left. However, components in an LDAP name must be specified as name/value pairs. The name “cn=Todd Sundsted, o=ComFrame, c=US” names the person “cn=Todd Sundsted” in the organization “o=ComFrame, c=US.” Likewise, the name “o=ComFrame, c=US” names the organization “o=ComFrame” in the country “c=US.”