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image: pandoc/core
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					image: pandoc/core
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pages:
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					pages:
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 script:
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						script:
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  - ./scripts/build-html.sh
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							- ./scripts/build-html.sh
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						artifacts:
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							paths:
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   - public/
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								-public
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 only:
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						only:
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							master
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								311/lec/lec10.md
									
									
									
									
									
								
							
							
						
						
									
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								311/lec/lec10.md
									
									
									
									
									
								
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lec1 
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					# lec10
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=====
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					 | 
				
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First we'll define some terminology.
 | 
					## TCP Structue
 | 
				
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 | 
					
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> Hosts
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					Sequence Numbers:
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 | 
					* byte stream _number_ of first byte in segment's data
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 | 
					
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End systems - typically don't bother with routing data through a network
 | 
					ACKS's: 
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 | 
					* seq # of next byte expected from other side
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 | 
					
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> Communication Links
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					Example: 
 | 
				
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 | 
					```
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 | 
					host a: user sends 'c'
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 | 
						seq=42, ack=79, data='c'
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 | 
					host b: ACK recepit send to host a(echo's back ''c')
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						seq=72, ack=49, data='c'	; data sent back from host b
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 | 
					```
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Typically the actual systems that connect things together.
 | 
					### Round trip time
 | 
				
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 | 
					
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Network edges
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					EstimatedRTT= (1-\alpha)*EstimatedRTT + \alpha*SampleRTT
 | 
				
			||||||
-------------
 | 
					 | 
				
			||||||
 | 
					
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Can be subdivided clients & servers and sometimes both at the same time.
 | 
					> Lot's of stuff missing here
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 | 
					
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Access network: cable network
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					## TCP Reliable data transfer
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-----------------------------
 | 
					
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 | 
					Implements:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					* Pipeplined segments
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			||||||
 | 
					* cumulative `ACK`
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			||||||
 | 
						* This just means that we assume that the highest sequenced ACK also means the previous segments have been received properly too
 | 
				
			||||||
 | 
					* Single transmission timer
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			||||||
 | 
					
 | 
				
			||||||
 | 
					### Sender Events
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			||||||
 | 
					
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			||||||
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					1. First create segment w/ seq no.
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			||||||
 | 
					
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			||||||
 | 
						a. Sequence number refers to byte in 
 | 
				
			||||||
 | 
					
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			||||||
 | 
					2. Start timer if we don't already have one.
 | 
				
			||||||
 | 
						
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			||||||
 | 
						a. Timer based off oldest UN-ACKED segment
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					## Retransmission w/ TCP
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			||||||
 | 
					
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			||||||
 | 
					__Timout__: Usually it's pretty long so if there is a timeout on a packet.
 | 
				
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 | 
					When this happens the receiver responds to sender with 3 ACK's for the last well received segment:
 | 
				
			||||||
 | 
					
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			||||||
 | 
					Receiver gets `1 2 3 5` but not `4`. We respond with the ACK for `1` like normal, then 3 ACK's for `1` is sent to the sender before the time out and we start re-sending from `2`.
 | 
				
			||||||
 | 
					This is what we call _fast retransmit_.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					_The main thing here is that the receiver controls the sender's "send rate" so that the receiver doesn't get inundated._
 | 
				
			||||||
 | 
					Receiver will _advertise_ free buffer space in including `rwnd` value in TCP header.
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			||||||
 | 
					This just tells the sender how much space is available to accept at a time.
 | 
				
			||||||
 | 
					
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			||||||
 | 
					Example: Transferring a large file from host to host.
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			||||||
 | 
					
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			||||||
 | 
					\alpha will send a file to \beta.
 | 
				
			||||||
 | 
					Alpha sends some file data to \beta, who then ACK's the packet but includes in the header that their buffer is full.
 | 
				
			||||||
 | 
					\alpha responds with a 1 byte packet to keep the connection alive.
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			||||||
 | 
					
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 | 
					
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 | 
					## Connection Management
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Before sender/receiver start exchanging anything we must perform a `handshake`.
 | 
				
			||||||
 | 
					`SYN` is a special packet type under TCP which we can use to synchronize both client and server.
 | 
				
			||||||
 | 
					
 | 
				
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 | 
					### Closing 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					`FIN` bit inside the header.
 | 
				
			||||||
 | 
					We send this off to a receiver and we enter a `close_wait` state.
 | 
				
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 | 
					We only wait because there might be more data.
 | 
				
			||||||
 | 
					Receiver enters the `close_wait` state as well, _but_, still sends any data left over.
 | 
				
			||||||
 | 
					Once the last `ACK` is sent we send a `FIN` packet
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Typically when have to share one line we can change the frequency of the
 | 
					 | 
				
			||||||
signal as one method to provide a distinguishment between different data
 | 
					 | 
				
			||||||
which may sometimes come from different sources.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
### Home Network
 | 
					 | 
				
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 | 
					
 | 
				
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Let's start with the modem. All it does it take some signla and convert
 | 
					 | 
				
			||||||
it to the proper IEEE data format(citation needed).
 | 
					 | 
				
			||||||
 | 
					
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Typically we would then pipe that data to a router which, given a
 | 
					 | 
				
			||||||
scenario for most houses, would forward that input data to whichever
 | 
					 | 
				
			||||||
machines requested the data.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
If you recall back to your discrete mathematics coursework various graph
 | 
					 | 
				
			||||||
topologies were covered and you likely noted that *star* topologies were
 | 
					 | 
				
			||||||
common for businesses since it makes it easist to send data from one
 | 
					 | 
				
			||||||
outside node on the star to another. In practice this would just mean
 | 
					 | 
				
			||||||
having the router/modem setup be one of the apendages of the star and
 | 
					 | 
				
			||||||
switch be in the middle so that the data only has to make two hops to
 | 
					 | 
				
			||||||
get anywhere in the network.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
> Doesn't that mean theres one node that could bring the whole network
 | 
					 | 
				
			||||||
> down at any time?
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Absolutely, which is why if you have a *very* small network with a
 | 
					 | 
				
			||||||
couple devices it's not really a problem but if you have an office full
 | 
					 | 
				
			||||||
of employees all with their own machines and wireless, printers,
 | 
					 | 
				
			||||||
servers, etc. then it's a huge problem. That's why typically a small
 | 
					 | 
				
			||||||
business or shop might be more inclined to use such a setup because: \*
 | 
					 | 
				
			||||||
It's easy to setup \* It's cheap to maintain
 | 
					 | 
				
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			|||||||
@ -1,32 +1,77 @@
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Active v Passive Attacks
 | 
					# Block Ciphers
 | 
				
			||||||
========================
 | 
					 | 
				
			||||||
 | 
					
 | 
				
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Base Definitions
 | 
					The main concept here is twofold:
 | 
				
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----------------
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					 | 
				
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 | 
					
 | 
				
			||||||
Passive: compromising a system but not necessarily doing anything apart
 | 
					* we take _blocks_ of data and cipher the _blocks_
 | 
				
			||||||
from *watching*
 | 
					* A given key is actually used to generate recursive keys to be further used on the data itself
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Active: compromising a system while doing something to the system apart
 | 
					 | 
				
			||||||
from infiltrating it
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Loosely speaking
 | 
					_bs example ahead_
 | 
				
			||||||
----------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
*Passive* can be just like listening in on a conversation(eavesdropping)
 | 
					Say we have a key 7 and some data 123456.
 | 
				
			||||||
where *active* is like jumping into the conversation and trying to do
 | 
					We take the whole data set and chunk it into blocks(for example): 12 34 56.
 | 
				
			||||||
something to it.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
When/How would either happen?
 | 
					Let's say our function here is to just add 7 to each block so we do the first step: 
 | 
				
			||||||
-----------------------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
If the result of an attack is to actually trigger some code to run then
 | 
					```
 | 
				
			||||||
usually we need to first gather the information required to understand
 | 
					12 + 7 = 19
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			||||||
how to make that happen. The reasoning is straightforward: if you don't
 | 
					Unlike other ciphers we don't reuse 7; instead we use the new thing as both the new key and part of our cipher text
 | 
				
			||||||
know how some system works then it's much harder to exploit that system.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Random example: Using a keylogger to log keystroke before sending those
 | 
					19 + 34 = 53
 | 
				
			||||||
logs to a server for processing could be a passive attack since you're
 | 
					Cipher: 1953..
 | 
				
			||||||
still in a *gathering data* sort of mode. Finally using that data to
 | 
					
 | 
				
			||||||
trying logging into some service would be the active portion of a
 | 
					53 + 56 = 109 <= let's pretend that this rolls over 99 and back to 00
 | 
				
			||||||
full-scale attack.
 | 
					          09  <= like this
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Final cipher: 195309
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					_It should be noted that in practice these functions usually take in huge keys and blocks_.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					> Deciphering
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Start from the back of the cipher not the front; if we used and xor function scheme (which is a symmetrical function) we would simply just xor the last block by itself and thus perform the same encryption scheme but in reverse.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Example::Encryption
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					Key: 110
 | 
				
			||||||
 | 
					Function scheme: xor
 | 
				
			||||||
 | 
					Data: 101 001 111
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					101 011 010
 | 
				
			||||||
 | 
					110 001 111
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					011 010 101 <= encrypted
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Example::Decryption
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					Ciphered: 011 010 101
 | 
				
			||||||
 | 
					Function scheme: xor
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					...
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# Feistal Cipher
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Two main components:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					1. each _thing_ in the data to cipher is replaced by a _ciphered thing_
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					2. nothing is added or deleted or replaced in sequence, instead the order of _things_ is changed.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Basically imagine that every _type of thing_ in our data maps to some other _type of thing/thing_ in the data and thus become swapped/reordered.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# DES - Data Encryption Standard
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Widely used until about 2001 when AES surpassed it as the newer(ish(kinda)) standard.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					DEA was the actual algorithm tho:
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					* 64 bit blocks
 | 
				
			||||||
 | 
					* 56 bit keys
 | 
				
			||||||
 | 
					* turns a 64-bit input into a 64-bit output (wew)
 | 
				
			||||||
 | 
					* Steps in reverse also reverse the encryption itself
 | 
				
			||||||
 | 
				
			|||||||
							
								
								
									
										178
									
								
								337/lec/lec10.md
									
									
									
									
									
								
							
							
						
						
									
										178
									
								
								337/lec/lec10.md
									
									
									
									
									
								
							@ -1,169 +1,41 @@
 | 
				
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lec1
 | 
					# lec11
 | 
				
			||||||
====
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
> What on earth?
 | 
					At this point I'l mention that just reading isn't going to get you anywhere, you have to try things, and give it a real earnest attempt.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
The first lecture has bee 50% syllabus 25% videos, 25% simple
 | 
					__ALU:__ Arithmetic Logic Unit
 | 
				
			||||||
terminology; expect nothing interesting for this section
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
General Performance Improvements in software
 | 
					## Building a 1-bit ALU 
 | 
				
			||||||
--------------------------------------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
In general we have a few options to increase performace in software;
 | 
					
 | 
				
			||||||
pipelining, parallelism, prediction.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
1.  Parallelism
 | 
					First we'll create an example _ALU_ which implements choosing between an `and`, `or`, `xor`, or `add`.
 | 
				
			||||||
 | 
					Whether or not our amazing _ALU_ is useful doesn't matter so we'll go one function at a time(besides `and/or`).
 | 
				
			||||||
 | 
					
 | 
				
			||||||
If we have multiple tasks to accomplish or multiple sources of data we
 | 
					First recognize that we need to choose between `and` or `or` against our two inputs A/B.
 | 
				
			||||||
might instead find it better to work on multiple things at
 | 
					This means we have two inputs and/or, and we need to select between them.
 | 
				
			||||||
once\[e.g. multi-threading, multi-core rendering\]
 | 
					_Try to do this on your own first!_
 | 
				
			||||||
 | 
					
 | 
				
			||||||
2.  Pipelining
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Here we are somehow taking *data* and serializing it into a linear form.
 | 
					Next we'll add on the `xor`.
 | 
				
			||||||
We do things like this because it could make sense to things
 | 
					Try doing this on your own but as far as hints go: don't be afraid to make changes to the mux.
 | 
				
			||||||
linearly\[e.g. taking data from a website response and forming it into a
 | 
					 | 
				
			||||||
struct/class instance in C++/Java et al.\].
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
3.  Prediction
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
If we can predict an outcome to avoid a bunch of computation then it
 | 
					Finally we'll add the ability to add and subtract. 
 | 
				
			||||||
could be worth to take our prediction and proceed with that instead of
 | 
					You may have also noted that we can subtract two things to see if they are the same however, we can also `not` the result of the `xor` and get the same result.
 | 
				
			||||||
the former. This happens **a lot** in cpu's where they use what's called
 | 
					 | 
				
			||||||
[branch prediction](https://danluu.com/branch-prediction/) to run even
 | 
					 | 
				
			||||||
faster.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Cost of Such Improvements
 | 
					
 | 
				
			||||||
-------------------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
As the saying goes: every decision you make as an engineer ultimately
 | 
					At this point our _ALU_ can `and`, `or`, `xor`, and `add`/`sub`.
 | 
				
			||||||
has a cost, let's look at the cost of these improvements.
 | 
					The mux will choose one which logic block to use; the carry-in line will tell the `add` logic block whether to add or subtract.
 | 
				
			||||||
 | 
					Finally the A-invert and B-invert line allow us to determine if we want to invert either A or B (inputs).
 | 
				
			||||||
 | 
					
 | 
				
			||||||
1.  Parallelism
 | 
					## N-bit ALU
 | 
				
			||||||
 | 
					
 | 
				
			||||||
If we have a data set which has some form of inter-dependencies between
 | 
					For sanity we'll use the following block for our new ALU.
 | 
				
			||||||
its members then we could easily run into the issue of waiting on other
 | 
					 | 
				
			||||||
things to finish.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Contrived Example:
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
    Premise: output file contents -> search lines for some text -> sort the resulting lines
 | 
					Note that we are chaining the carry-in's to the carry-out's just like a ripple adder.
 | 
				
			||||||
 | 
					also each ALU just works with `1` bit from our given 4-bit input.
 | 
				
			||||||
    We have to do the following processes:
 | 
					 | 
				
			||||||
    print my-file.data 
 | 
					 | 
				
			||||||
    search file
 | 
					 | 
				
			||||||
    sort results of the search
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    In bash we might do: cat my-file.data | grep 'Text to search for' | sort
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Parallelism doesn't make sense here for one reason: this series of
 | 
					 | 
				
			||||||
proccesses don't benefit from parallelism because the 2nd and 3rd tasks
 | 
					 | 
				
			||||||
*must* wait until the previous ones finish first.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
2.  Pipelining
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Let's say we want to do the following:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Search file1 for some text : [search file1] 
 | 
					 | 
				
			||||||
    Feed the results of the search into a sorting program [sort]
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    Search file2 for some text  [search file2]
 | 
					 | 
				
			||||||
    Feed the results of the search into a reverse sorting program [reverse sort]
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    The resulting Directed Acyclic Graph looks like
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    [search file1] => [sort]
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    [search file2] => [reverse sort]
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Making the above linear means we effectively have to:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    [search file1] => [sort] [search file2] => [reverse sort]
 | 
					 | 
				
			||||||
    | proc2 waiting........| 
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Which wastes a lot of time if the previous process is going to take a
 | 
					 | 
				
			||||||
long time. Bonus points if process 2 is extremely short.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
3.  Prediction
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Ok two things up front:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
-   First: prediction's fault is that we could be wrong and have to end
 | 
					 | 
				
			||||||
    up doing hard computations.
 | 
					 | 
				
			||||||
-   Second: *this course never covers branch prediction(something that
 | 
					 | 
				
			||||||
    pretty much every cpu in the last 20 years out there does)* so I'm
 | 
					 | 
				
			||||||
    gonna cover it here; ready, let's go.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
For starters let's say a basic cpu takes instructions sequentially in
 | 
					 | 
				
			||||||
memory: `A B C D`. However this is kinda slow because there is *time*
 | 
					 | 
				
			||||||
between getting instructions, decoding it to know what instruction it is
 | 
					 | 
				
			||||||
and finally executing it proper. For this reason modern CPU's actually
 | 
					 | 
				
			||||||
fetch, decode, and execute(and more!) instructions all at the same time.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Instead of getting instructions like this:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    0
 | 
					 | 
				
			||||||
     AA
 | 
					 | 
				
			||||||
       BB
 | 
					 | 
				
			||||||
         CC
 | 
					 | 
				
			||||||
           DD 
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
We actually do something more like this
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    A
 | 
					 | 
				
			||||||
     AB
 | 
					 | 
				
			||||||
       BC
 | 
					 | 
				
			||||||
         CD
 | 
					 | 
				
			||||||
           D0
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If it doesn't seem like much remember this is half an instruction on a
 | 
					 | 
				
			||||||
chip that is likely going to process thousands/millions of instructions
 | 
					 | 
				
			||||||
so the savings scales really well.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
This scheme is fine if our instructions are all coming one after the
 | 
					 | 
				
			||||||
other in memory, but if we need to branch then we likely need to jump to
 | 
					 | 
				
			||||||
a new location like so.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    ABCDEFGHIJKL
 | 
					 | 
				
			||||||
    ^^^*     ^
 | 
					 | 
				
			||||||
       |-----|
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Now say we have the following code:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
    if (x == 123) {
 | 
					 | 
				
			||||||
        main_call();
 | 
					 | 
				
			||||||
    }
 | 
					 | 
				
			||||||
    else {
 | 
					 | 
				
			||||||
        alternate_call();
 | 
					 | 
				
			||||||
    }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The (psuedo)assembly might look like
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
``` {.asm}
 | 
					 | 
				
			||||||
    cmp x, 123 
 | 
					 | 
				
			||||||
    je second
 | 
					 | 
				
			||||||
main_branch:    ; pointless label but nice for reading
 | 
					 | 
				
			||||||
    call main_call
 | 
					 | 
				
			||||||
    jmp end
 | 
					 | 
				
			||||||
second:
 | 
					 | 
				
			||||||
    call alternate_call
 | 
					 | 
				
			||||||
end:
 | 
					 | 
				
			||||||
    ; something to do here
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Our problem comes when we hit the je. Once we've loaded that instruction
 | 
					 | 
				
			||||||
and can start executing it, we have to make a decision, load the
 | 
					 | 
				
			||||||
`call main_call` instruction or the `call alternate_call`? Chances are
 | 
					 | 
				
			||||||
that if we guess we have a 50% change of saving time and 50% chance of
 | 
					 | 
				
			||||||
tossing out our guess and starting the whole *get instruction =\> decode
 | 
					 | 
				
			||||||
etc.* process over again from scratch.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Solution 1:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Try do determine what branches are taken prior to running the program
 | 
					 | 
				
			||||||
and just always guess the more likely branches. If we find that the
 | 
					 | 
				
			||||||
above branch calls `main_branch` more often then we should load that
 | 
					 | 
				
			||||||
branch always; knowing that the loss from being wrong is offset by the
 | 
					 | 
				
			||||||
gain from the statistically more often correct branches.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
...
 | 
					 | 
				
			||||||
 | 
				
			|||||||
@ -10,76 +10,29 @@ Most typically we deal with binary(when we do) in nibbles or 4 _bit_ chunks whic
 | 
				
			|||||||
Ex:`0101 1100` is a basic random byte.
 | 
					Ex:`0101 1100` is a basic random byte.
 | 
				
			||||||
For most sane solutions this is essentially the only way we __ever__ deal with binary.
 | 
					For most sane solutions this is essentially the only way we __ever__ deal with binary.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> Why can't we (((save bits))) and not use nibbles?
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
In truth you can totally do that; but not really.
 | 
					 | 
				
			||||||
To explain let's look at some higher level C/C++ code; say you had this structure: 
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
struct Point {
 | 
					 | 
				
			||||||
	int x; // specifying width for clarity sake
 | 
					 | 
				
			||||||
	int y;
 | 
					 | 
				
			||||||
	unsigned int valid : 1;
 | 
					 | 
				
			||||||
};
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
On a typical x86 system(and many x64 systems) with no compile time optimizations this structure might look like: 
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
32(int x) + 32(int y) + 1(unsigned int valid) + 7(bits of padding)
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Why? Because while we can always calculate the address of a particular byte's address in memory we cant' or rather don't even try to do the same for bits.
 | 
					 | 
				
			||||||
The reason is simple: a 32bit CPU can calulate any number inclusively between `0` and `0xffffffff` or `4294967295`. That means we have an entropy pool large enough to have 1 number per byte but not enough to include the bits as well.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If we use that `valid` _bit-field_ in our code later like
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
if(point_ref->valid) {
 | 
					 | 
				
			||||||
	/* do stuff */
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
The machine code instructions generated will really just check if that byte(which contains the bit we care about) is a non-zero value.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If the bit is set we have (for example) `0b0000 0001` thus a _true_ value.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
## Two's Complement - aka Negate 
 | 
					## Two's Complement - aka Negate 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
To find the Negation of any bit-string: 
 | 
					To find the Negation of any bit-string: 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
i.e. `3 * -1=> -3` 
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
1. Flip all bits in the bit-string
 | 
					1. Flip all bits in the bit-string
 | 
				
			||||||
2. Add 1 to the bitstring
 | 
					2. Add 1 to the bitstring
 | 
				
			||||||
 | 
					
 | 
				
			||||||
The case for 3:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
start off: 0011 => 3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
flip bits: 1100 => -2
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
add one: 1101 => -3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
```
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
### Signedness 
 | 
					### Signedness 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> Why? 
 | 
					> Why? 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Because this matters for dealing with `signed` and `unsigned` values. _No it doesn't mean positive and negative numbers._
 | 
					Because this matters for dealing with `signed` and `unsigned` values. _No it doesn't mean positive and negative numbers._
 | 
				
			||||||
Say we have 4 bytes to mess with. This means we have a range of 0000 to 1111. If we wanted purely positive numbers in this range we could have 0000 to 1111... or 0 to 15.
 | 
					Say we have 4 bytes to mess with. This means we have a range of 0000 to 1111. If we wanted pureley positive numbers in this range we could have 0000 to 1111... or 0 to 15.
 | 
				
			||||||
If we needed negative representation however, we have to sacrifice some of our range.
 | 
					If we needed negative represenation however, we have to sacrifice some of our range.
 | 
				
			||||||
Our new unsigned range is then `0-7` _or in binary_: `0000 - 0111`. We say unsigned for this range because the largest number we can represent without setting the first bit is `0111` => `7`.
 | 
					Our new unsigned range is 0-7. We say it's unsigned because the first bit here is 0.
 | 
				
			||||||
Our negative range is then `-8 -> -1` which in binary is `0b1000 -> 0b1111`
 | 
					If it were 1 we would have a _signed_ number. 
 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
## Intro to hex
 | 
					## Intro to hex
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> Hex Notation 0x... 
 | 
					> Hex Notation 0x... 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
x86 assemblersi(masm) will typically accept `...h` as a postfix notation.
 | 
					x86 assemblersi(masm) will typically accept `...h`
 | 
				
			||||||
 | 
					
 | 
				
			||||||
More convinient than binary for obvious reasons; namely it doesn't look like spaghetti on the screen.
 | 
					More convinient than binary for obvious reasons; namely it doesn't look like spaghetti on the screen.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
@ -88,29 +41,24 @@ More pedantically our new hex range is 0x00 to 0xff.
 | 
				
			|||||||
 | 
					
 | 
				
			||||||
> Binary mapped 
 | 
					> Binary mapped 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
It happens that 1 nibble makes up 0x0 to 0xF. 
 | 
					It happens that 1 nibble makes up 0x00 to 0xFF. 
 | 
				
			||||||
So for now just get used to converting {0000-1111} to one of it's respective values in hex and eventually it should be second nature.
 | 
					So for now just get used to converting {0000-1111} to one of it's respective values in hex and evetually it should be second nature.
 | 
				
			||||||
Then just move on to using hex(like immediately after these lessons), because writing actual binary is actually awful.
 | 
					Then just move on to using hex(like immediately after these lessons).
 | 
				
			||||||
 | 
					Even the most obfuscated binary files out there don't resort to architectural obfuscation; until they do.
 | 
				
			||||||
> Dude trust me hex is way better to read than decimal
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
It may seem convenient at first but after a while you'll realized that hex has really easy to understand uses and makes this super clear + concise, especially when dealing with bit masks and bitsets.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
> Ascii in Hex Dumps 
 | 
					> Ascii in Hex Dumps 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Kind of a side note but most ascii text values range from 0x21 to 0x66 so if you're looking for text in a binary look for groupings of that value.
 | 
					Kind of a side note but most ascii text is from 0x21 to 0x66ish[citation needed]
 | 
				
			||||||
 | 
					
 | 
				
			||||||
## 32 v 64 bit 
 | 
					## 32 v 64 bit 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
In case you come from an x86_64 ish background know that in MIPS terminology changes a bit(bun intended).
 | 
					For those with a 32 bit background know that these notes deal with 64-bit architecutres mostly. So some quick terminology which might randomly throw you off anyway.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> x86 byte = mips byte
 | 
					> double-byte/ half-word 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> x86 word = mips half word
 | 
					The latter is dumb but soemtimes used so wtever.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> x86 dword = mips word
 | 
					> word = 4 bytes
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> x86/64 qword = mips mips dword
 | 
					Etc onward with doubles, quads...
 | 
				
			||||||
 | 
					
 | 
				
			||||||
So just keep those translations in mind...
 | 
					 | 
				
			||||||
 | 
				
			|||||||
@ -1,19 +1,22 @@
 | 
				
			|||||||
# Lecture 3
 | 
					# lec3
 | 
				
			||||||
 | 
					
 | 
				
			||||||
## One's & Two's Complement (in depth(or something))
 | 
					## One's & Two's Complement
 | 
				
			||||||
 | 
					
 | 
				
			||||||
In order to change recall from last lecture that we wanted to represent `3` with a single nibble like so `0b0011`.
 | 
					_Previous lecture went over signedness of numbers so this section won't as much_.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
To make this into a `-3` we:
 | 
					First we'll deal with flipping bits: this is where you may hear the term _1's complement_.
 | 
				
			||||||
 | 
					While not very useful on it's own for most purposes it does help get closer to creating a seperation between _positive_ and _negative_ numbers.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
1. Flipped all the bits : `value xor 0xff..`
 | 
					The only other step after flipping all the bits is just adding 1.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
2. Added 1 to the result of step 1
 | 
					`1001 1110` becomes `0110 0010`.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
> Ok, but like, why do I care? we're just multiplying things by -1 how does that matter at all?
 | 
					> shouldn't that last 2 bits be 01?
 | 
				
			||||||
 | 
					
 | 
				
			||||||
It matters because certain types operations _just suck_ on pretty much every general use platform.
 | 
					Close, the reason why we have `b10` is because if we: `b01 + b1` the `1` will carry over to the next bit.
 | 
				
			||||||
 | 
					The actual term for this is just __negate__; the other way around is essentially cannon fodder.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					>Ok, but what does that look like _assembly_ the thing I came here to learn.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Most assemblers accept something like `neg targetValue` however you can also use an _exclusive or_[`xor targetValue, 0xFF`]. Keep in mind that the immediate value should be sign-extended to reflect the proper targetValue size.
 | 
					Most assemblers accept something like `neg targetValue` however you can also use an _exclusive or_[`xor targetValue, 0xFF`]. Keep in mind that the immediate value should be sign-extended to reflect the proper targetValue size.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
				
			|||||||
@ -1,47 +1,43 @@
 | 
				
			|||||||
lec1
 | 
					# lec10
 | 
				
			||||||
====
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Databases introduction
 | 
					This lecture has a corresponding lab excercise who's instructions can be found in `triggers-lab.pdf`.
 | 
				
			||||||
----------------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
First off why do we even need a database and what do they accomplish?
 | 
					## What is a trigger
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Generally a databse will have 3 core elements to it:
 | 
					Something that executes when _some operation_ is performed
 | 
				
			||||||
 | 
					
 | 
				
			||||||
1.  querying
 | 
					## Structure 
 | 
				
			||||||
    -   Finding things
 | 
					 | 
				
			||||||
        -   Just as well structured data makes querying easier
 | 
					 | 
				
			||||||
2.  access control
 | 
					 | 
				
			||||||
    -   who can access which data segments and what they can do with
 | 
					 | 
				
			||||||
        that data
 | 
					 | 
				
			||||||
        -   reading, writing, sending, etc
 | 
					 | 
				
			||||||
3.  corruption prevention
 | 
					 | 
				
			||||||
    -   mirroring/raid/parity checking/checksums/etc as some examples
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Modeling Data
 | 
					```
 | 
				
			||||||
-------------
 | 
					create trigger NAME before some_operation
 | 
				
			||||||
 | 
					when(condition)
 | 
				
			||||||
 | 
					begin
 | 
				
			||||||
 | 
						do_something
 | 
				
			||||||
 | 
					end;
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Just like other data problems we can choose what model we use to deal
 | 
					To explain: First we `create trigger` followed by some trigger name.
 | 
				
			||||||
with data. In the case for sqlite3 the main data model we have are
 | 
					Then we have to denote that this trigger should fire whenever some operation happens.
 | 
				
			||||||
tables, where we store our pertinent data, and later we'll learn even
 | 
					This trigger then executes everything in the `begin...end;` section _before_ the new operation happens.
 | 
				
			||||||
data about our data is stored in tables.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Because everything goes into a table, it means we also have to have a
 | 
					> `after`
 | 
				
			||||||
plan for *how* we want to lay out our data in the table. The **schema**
 | 
					 | 
				
			||||||
is that design/structure for our databse. The **instance** is the
 | 
					 | 
				
			||||||
occurance of that schema with some data inside the fields, i.e. we have
 | 
					 | 
				
			||||||
a table sitting somewhere in the databse which follows the given
 | 
					 | 
				
			||||||
structure of a aforemention schema.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
**Queries** are typically known to be declarative; typically we don't
 | 
					Likewise if we want to fire a trigger _after_ some operation we ccan just replace the before keyword with `after`.
 | 
				
			||||||
care about what goes on behind the scenes in practice since by this
 | 
					
 | 
				
			||||||
point we are assuming we have tools we trust and know to be somewhat
 | 
					> `new.adsf`
 | 
				
			||||||
efficient.
 | 
					
 | 
				
			||||||
 | 
					Refers to _new_ value being added to a table.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					> `old.adsf` 
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Refers to _old_ vvalue being changed in a table.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
						
 | 
				
			||||||
 | 
					## Trigger Metadata
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					If you want to look at what triggers exist you can query the `sql_master` table.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					select * from sql_master where name='trigger';
 | 
				
			||||||
 | 
					```
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Finally we have **transactions** which are a set of operations who are
 | 
					 | 
				
			||||||
not designed to only commit if they are completed successfully.
 | 
					 | 
				
			||||||
Transactions are not alllowed to fail. If *anything* fails then
 | 
					 | 
				
			||||||
everything should be undone and the state should revert to previous
 | 
					 | 
				
			||||||
state. This is useful because if we are, for example, transferring money
 | 
					 | 
				
			||||||
to another account we want to make sure that the exchange happens
 | 
					 | 
				
			||||||
seamlessly otherwise we should back out of the operation altogether.
 | 
					 | 
				
			||||||
 | 
				
			|||||||
@ -88,7 +88,7 @@ if __name__ == "__main__":
 | 
				
			|||||||
 | 
					
 | 
				
			||||||
    # build up our heap to display info from
 | 
					    # build up our heap to display info from
 | 
				
			||||||
    heap = encode(frequencies)[0]
 | 
					    heap = encode(frequencies)[0]
 | 
				
			||||||
    print(heap)
 | 
					    #print(heap)
 | 
				
			||||||
 | 
					
 | 
				
			||||||
    # decode the binary
 | 
					    # decode the binary
 | 
				
			||||||
    decode(heap, binary)
 | 
					    decode(heap, binary)
 | 
				
			||||||
 | 
				
			|||||||
@ -1,35 +1,38 @@
 | 
				
			|||||||
A\* Pathfinding
 | 
					# Adjacency list
 | 
				
			||||||
===============
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
There are 3 main values usedd in reference to A\*:
 | 
					Imagine 8 nodes with no connections
 | 
				
			||||||
 | 
					
 | 
				
			||||||
    f = how promisiing a new location is
 | 
					To store this data in an _adjacency list_ we need __n__ items to store them.
 | 
				
			||||||
    g = distance from origin
 | 
					We'll have 0 __e__dges however so in total our space is (n+e) == (n)
 | 
				
			||||||
    h = estimate distance to goal
 | 
					 | 
				
			||||||
    f = g + h
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
For a grid space our `h` is calculated by two straight shots to the goal
 | 
					# Adjacency matrix
 | 
				
			||||||
from the current location(ignore barriers). The grid space `g` value is
 | 
					 | 
				
			||||||
basiccally the number of steps we've taken from the origin. We maintain
 | 
					 | 
				
			||||||
a list of potential nodes only, so if one of the seeking nodes gets us
 | 
					 | 
				
			||||||
stuck we can freely remove that, because it succs.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Time & Space Commplexities
 | 
					space: O(n^2)
 | 
				
			||||||
==========================
 | 
					The convention for notation btw is [x,y] meaning:
 | 
				
			||||||
 | 
						* _from x to y_
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Best-First Search
 | 
					# Breadth first search
 | 
				
			||||||
-----------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Time: O(VlogV + E)
 | 
					add neighbors of current to queue
 | 
				
			||||||
 | 
					go through current's neighbors and add their neighbors to queue
 | 
				
			||||||
 | 
					add neighbor's neighbors
 | 
				
			||||||
 | 
						keep going until there are no more neighbors to add
 | 
				
			||||||
 | 
					go through queue and start popping members out of the queue
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Dijkstra's
 | 
					# Depth first search 
 | 
				
			||||||
----------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
O(V\^2 + E)
 | 
					Here we're going deeper into the neighbors
 | 
				
			||||||
 | 
					
 | 
				
			||||||
A\*
 | 
					_once we have a starting point_ 
 | 
				
			||||||
---
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Worst case is the same as Dijkstra's time
 | 
					_available just means that node has a non-visited neighbor_
 | 
				
			||||||
 | 
					if available go to a neighbor
 | 
				
			||||||
 | 
					if no neighbors available visit
 | 
				
			||||||
 | 
					goto 1
 | 
				
			||||||
 | 
					
 | 
				
			||||||
O(V\^2 + E)
 | 
					# Kahn Sort
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# Graph Coloring
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					When figuring out how many colors we need for the graph, we should note the degree of the graph
 | 
				
			||||||
 | 
				
			|||||||
@ -1,60 +1,69 @@
 | 
				
			|||||||
Data storage
 | 
					# Hardware deployment Strategies
 | 
				
			||||||
============
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Spinning Disks
 | 
					 | 
				
			||||||
--------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Cheaper for more storage
 | 
					## Virtual Desktop Interface
 | 
				
			||||||
 | 
					
 | 
				
			||||||
RAID - Redundant Array of Independent Disk
 | 
					aka 0-Clients: network hosted OS is what each client would use.
 | 
				
			||||||
------------------------------------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Raid 0: basically cramming multiple drives and treating them as one.
 | 
					In some cases that network is a pool of servers which are tapped into.
 | 
				
			||||||
Data is striped across the drives but if one fails then you literally
 | 
					Clients can vary in specs like explained below(context: university):
 | 
				
			||||||
lose a chunk of data.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Raid 1: data is mirrored across the drives so it's completely redundant
 | 
					> Pool for a Library
 | 
				
			||||||
so if one fails the other is still alive. It's not a backup however
 | 
					 | 
				
			||||||
since file updates will affect all the drives.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Raid 5: parity. Combining multiple drives allows us to establish the
 | 
					Clients retain low hardware specs since most are just using office applications and not much else.
 | 
				
			||||||
parity of the data on other drives to recover that data if it goes
 | 
					 | 
				
			||||||
missing.(min 3 drives)
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Raid 6: same in principle as raid 5 but this time we have an extra drive
 | 
					> Pool for an Engineering department
 | 
				
			||||||
for just parity.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Raid 10: 0 and 1 combined to have a set of drives in raid 0 and putting
 | 
					Clients connect to another pool where both clients and pool have better hardware specs/resources.
 | 
				
			||||||
those together in raid 1 with another equally sized set of drives.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Network Attached Storage - NAS
 | 
					The downside is that there is _1 point of failure_.
 | 
				
			||||||
------------------------------
 | 
					The pool goes down and so does everyone else, meaning downtime is going to cost way more than a single machine going down.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Basically space stored on the local network.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Storage Attached Network - SAN
 | 
					 | 
				
			||||||
------------------------------
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Applicable when we virtualise whole os's for users, we use a storage
 | 
					# Server Hardware Strategies
 | 
				
			||||||
device attached to the network to use different operating systems
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Managing Storage
 | 
					> All eggs in one basket
 | 
				
			||||||
================
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Outsourcing the storage for users to services like Onedrive because it
 | 
					Imagine just one server doing everything
 | 
				
			||||||
becomes their problem and not ours.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Storage as a Service
 | 
					* Important to maintain redundancy in this case
 | 
				
			||||||
====================
 | 
					* Upgrading is a pain sometimes
 | 
				
			||||||
 | 
					
 | 
				
			||||||
Ensure that the OS gets its own space/partition on a drive and give the
 | 
					 | 
				
			||||||
user their own partition to ruin. That way the OS(windows) will just
 | 
					 | 
				
			||||||
fill its partition into another dimension.
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Backup
 | 
					> Buy in bulk, allocate fractions
 | 
				
			||||||
======
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
Other people's data is in your hands so make sure that you backup data
 | 
					Basically have a server that serves up varies virtual machines.
 | 
				
			||||||
in some way. Some external services can be nice if you find that you
 | 
					# Live migration
 | 
				
			||||||
constantly need to get to your backups. Tape records are good for
 | 
					
 | 
				
			||||||
archival purposes; keep in mind that they are slow as hell.
 | 
					Allows us to move live running virtual machines onto new servers if that server is running out of resources.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# Containers
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					_docker_: Virtualize the service, not the whole operating system
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# Server Hardware Features
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					> Things that server's benefit from
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					* fast i/o
 | 
				
			||||||
 | 
					* low latency cpu's(xeons > i series)
 | 
				
			||||||
 | 
					* expansion slots
 | 
				
			||||||
 | 
					* lots of network ports available
 | 
				
			||||||
 | 
					* EC memory
 | 
				
			||||||
 | 
					* Remote control
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Patch/Version control on server's
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Scheduling is usually slow/more lax so that server's don't just randomly break all the time.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# Misc
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Uptime: more uptime is _going_ to be more expensive. Depending on what you're doing figure out how much downtime you can afford.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					# Specs
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Like before _ecc memory_ is basically required for servers, good number of network interfaces, and solid disks management.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					Remember that the main parameters for choosing hardware is going to be budget, and necessity; basically what can you get away with on the budget at hand.
 | 
				
			||||||
 | 
				
			|||||||
@ -1,23 +0,0 @@
 | 
				
			|||||||
# Alejandro's Notes
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Here you will find all the notes in reference book format below.
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
If some of this information is inaccurate or missing details please feel free to submit a merge request or contact me via Email/Discord:
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* Email: alejandros714@protonmail.com
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* Discord: shockrah#2647
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
* Public Repository: [gitlab.com/shockrah/csnotes](https://gitlab.com/shockrah/csnotes/)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
[Intro to Networking](intro-to-networking-311.html)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
[Networking Administration](network-administration-412.html)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
[Networking and Security Concepts](network-security-concepts-312.html)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
[Intro to Databases](intro-to-databases-363.html)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
[Advanced Algorithms](advanced-algorithms-370.html)
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
[Computer Architecture with MIPS](computer-architecture-337.html)
 | 
					 | 
				
			||||||
@ -1,328 +0,0 @@
 | 
				
			|||||||
/*
 | 
					 | 
				
			||||||
 * I add this to html files generated with pandoc.
 | 
					 | 
				
			||||||
 */
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
html {
 | 
					 | 
				
			||||||
  font-size: 100%;
 | 
					 | 
				
			||||||
  overflow-y: scroll;
 | 
					 | 
				
			||||||
  -webkit-text-size-adjust: 100%;
 | 
					 | 
				
			||||||
  -ms-text-size-adjust: 100%;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
body {
 | 
					 | 
				
			||||||
  color: #444;
 | 
					 | 
				
			||||||
  font-family: Georgia, Palatino, 'Palatino Linotype', Times, 'Times New Roman', serif;
 | 
					 | 
				
			||||||
  font-size: 12px;
 | 
					 | 
				
			||||||
  line-height: 1.7;
 | 
					 | 
				
			||||||
  padding: 1em;
 | 
					 | 
				
			||||||
  margin: auto;
 | 
					 | 
				
			||||||
  max-width: 42em;
 | 
					 | 
				
			||||||
  background: #fefefe;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a {
 | 
					 | 
				
			||||||
  color: #0645ad;
 | 
					 | 
				
			||||||
  text-decoration: none;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a:visited {
 | 
					 | 
				
			||||||
  color: #0b0080;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a:hover {
 | 
					 | 
				
			||||||
  color: #06e;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a:active {
 | 
					 | 
				
			||||||
  color: #faa700;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a:focus {
 | 
					 | 
				
			||||||
  outline: thin dotted;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
*::-moz-selection {
 | 
					 | 
				
			||||||
  background: rgba(255, 255, 0, 0.3);
 | 
					 | 
				
			||||||
  color: #000;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
*::selection {
 | 
					 | 
				
			||||||
  background: rgba(255, 255, 0, 0.3);
 | 
					 | 
				
			||||||
  color: #000;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a::-moz-selection {
 | 
					 | 
				
			||||||
  background: rgba(255, 255, 0, 0.3);
 | 
					 | 
				
			||||||
  color: #0645ad;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
a::selection {
 | 
					 | 
				
			||||||
  background: rgba(255, 255, 0, 0.3);
 | 
					 | 
				
			||||||
  color: #0645ad;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
p {
 | 
					 | 
				
			||||||
  margin: 1em 0;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
img {
 | 
					 | 
				
			||||||
  max-width: 100%;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h1, h2, h3, h4, h5, h6 {
 | 
					 | 
				
			||||||
  color: #111;
 | 
					 | 
				
			||||||
  line-height: 125%;
 | 
					 | 
				
			||||||
  margin-top: 2em;
 | 
					 | 
				
			||||||
  font-weight: normal;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h4, h5, h6 {
 | 
					 | 
				
			||||||
  font-weight: bold;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h1 {
 | 
					 | 
				
			||||||
  font-size: 2.5em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h2 {
 | 
					 | 
				
			||||||
  font-size: 2em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h3 {
 | 
					 | 
				
			||||||
  font-size: 1.5em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h4 {
 | 
					 | 
				
			||||||
  font-size: 1.2em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h5 {
 | 
					 | 
				
			||||||
  font-size: 1em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
h6 {
 | 
					 | 
				
			||||||
  font-size: 0.9em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
blockquote {
 | 
					 | 
				
			||||||
  color: #666666;
 | 
					 | 
				
			||||||
  margin: 0;
 | 
					 | 
				
			||||||
  padding-left: 3em;
 | 
					 | 
				
			||||||
  border-left: 0.5em #EEE solid;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
hr {
 | 
					 | 
				
			||||||
  display: block;
 | 
					 | 
				
			||||||
  height: 2px;
 | 
					 | 
				
			||||||
  border: 0;
 | 
					 | 
				
			||||||
  border-top: 1px solid #aaa;
 | 
					 | 
				
			||||||
  border-bottom: 1px solid #eee;
 | 
					 | 
				
			||||||
  margin: 1em 0;
 | 
					 | 
				
			||||||
  padding: 0;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
pre, code, kbd, samp {
 | 
					 | 
				
			||||||
  color: #000;
 | 
					 | 
				
			||||||
  font-family: monospace, monospace;
 | 
					 | 
				
			||||||
  _font-family: 'courier new', monospace;
 | 
					 | 
				
			||||||
  font-size: 0.98em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
pre {
 | 
					 | 
				
			||||||
  white-space: pre;
 | 
					 | 
				
			||||||
  white-space: pre-wrap;
 | 
					 | 
				
			||||||
  word-wrap: break-word;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
b, strong {
 | 
					 | 
				
			||||||
  font-weight: bold;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
dfn {
 | 
					 | 
				
			||||||
  font-style: italic;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
ins {
 | 
					 | 
				
			||||||
  background: #ff9;
 | 
					 | 
				
			||||||
  color: #000;
 | 
					 | 
				
			||||||
  text-decoration: none;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
mark {
 | 
					 | 
				
			||||||
  background: #ff0;
 | 
					 | 
				
			||||||
  color: #000;
 | 
					 | 
				
			||||||
  font-style: italic;
 | 
					 | 
				
			||||||
  font-weight: bold;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
sub, sup {
 | 
					 | 
				
			||||||
  font-size: 75%;
 | 
					 | 
				
			||||||
  line-height: 0;
 | 
					 | 
				
			||||||
  position: relative;
 | 
					 | 
				
			||||||
  vertical-align: baseline;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
sup {
 | 
					 | 
				
			||||||
  top: -0.5em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
sub {
 | 
					 | 
				
			||||||
  bottom: -0.25em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
ul, ol {
 | 
					 | 
				
			||||||
  margin: 1em 0;
 | 
					 | 
				
			||||||
  padding: 0 0 0 2em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
li p:last-child {
 | 
					 | 
				
			||||||
  margin-bottom: 0;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
ul ul, ol ol {
 | 
					 | 
				
			||||||
  margin: .3em 0;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
dl {
 | 
					 | 
				
			||||||
  margin-bottom: 1em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
dt {
 | 
					 | 
				
			||||||
  font-weight: bold;
 | 
					 | 
				
			||||||
  margin-bottom: .8em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
dd {
 | 
					 | 
				
			||||||
  margin: 0 0 .8em 2em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
dd:last-child {
 | 
					 | 
				
			||||||
  margin-bottom: 0;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
img {
 | 
					 | 
				
			||||||
  border: 0;
 | 
					 | 
				
			||||||
  -ms-interpolation-mode: bicubic;
 | 
					 | 
				
			||||||
  vertical-align: middle;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
figure {
 | 
					 | 
				
			||||||
  display: block;
 | 
					 | 
				
			||||||
  text-align: center;
 | 
					 | 
				
			||||||
  margin: 1em 0;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
figure img {
 | 
					 | 
				
			||||||
  border: none;
 | 
					 | 
				
			||||||
  margin: 0 auto;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
figcaption {
 | 
					 | 
				
			||||||
  font-size: 0.8em;
 | 
					 | 
				
			||||||
  font-style: italic;
 | 
					 | 
				
			||||||
  margin: 0 0 .8em;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
table {
 | 
					 | 
				
			||||||
  margin-bottom: 2em;
 | 
					 | 
				
			||||||
  border-bottom: 1px solid #ddd;
 | 
					 | 
				
			||||||
  border-right: 1px solid #ddd;
 | 
					 | 
				
			||||||
  border-spacing: 0;
 | 
					 | 
				
			||||||
  border-collapse: collapse;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
table th {
 | 
					 | 
				
			||||||
  padding: .2em 1em;
 | 
					 | 
				
			||||||
  background-color: #eee;
 | 
					 | 
				
			||||||
  border-top: 1px solid #ddd;
 | 
					 | 
				
			||||||
  border-left: 1px solid #ddd;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
table td {
 | 
					 | 
				
			||||||
  padding: .2em 1em;
 | 
					 | 
				
			||||||
  border-top: 1px solid #ddd;
 | 
					 | 
				
			||||||
  border-left: 1px solid #ddd;
 | 
					 | 
				
			||||||
  vertical-align: top;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
.author {
 | 
					 | 
				
			||||||
  font-size: 1.2em;
 | 
					 | 
				
			||||||
  text-align: center;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
@media only screen and (min-width: 480px) {
 | 
					 | 
				
			||||||
  body {
 | 
					 | 
				
			||||||
    font-size: 14px;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
@media only screen and (min-width: 768px) {
 | 
					 | 
				
			||||||
  body {
 | 
					 | 
				
			||||||
    font-size: 16px;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
@media print {
 | 
					 | 
				
			||||||
  * {
 | 
					 | 
				
			||||||
    background: transparent !important;
 | 
					 | 
				
			||||||
    color: black !important;
 | 
					 | 
				
			||||||
    filter: none !important;
 | 
					 | 
				
			||||||
    -ms-filter: none !important;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  body {
 | 
					 | 
				
			||||||
    font-size: 12pt;
 | 
					 | 
				
			||||||
    max-width: 100%;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  a, a:visited {
 | 
					 | 
				
			||||||
    text-decoration: underline;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  hr {
 | 
					 | 
				
			||||||
    height: 1px;
 | 
					 | 
				
			||||||
    border: 0;
 | 
					 | 
				
			||||||
    border-bottom: 1px solid black;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  a[href]:after {
 | 
					 | 
				
			||||||
    content: " (" attr(href) ")";
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  abbr[title]:after {
 | 
					 | 
				
			||||||
    content: " (" attr(title) ")";
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  .ir a:after, a[href^="javascript:"]:after, a[href^="#"]:after {
 | 
					 | 
				
			||||||
    content: "";
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  pre, blockquote {
 | 
					 | 
				
			||||||
    border: 1px solid #999;
 | 
					 | 
				
			||||||
    padding-right: 1em;
 | 
					 | 
				
			||||||
    page-break-inside: avoid;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  tr, img {
 | 
					 | 
				
			||||||
    page-break-inside: avoid;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  img {
 | 
					 | 
				
			||||||
    max-width: 100% !important;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  @page :left {
 | 
					 | 
				
			||||||
    margin: 15mm 20mm 15mm 10mm;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  @page :right {
 | 
					 | 
				
			||||||
    margin: 15mm 10mm 15mm 20mm;
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  p, h2, h3 {
 | 
					 | 
				
			||||||
    orphans: 3;
 | 
					 | 
				
			||||||
    widows: 3;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
  h2, h3 {
 | 
					 | 
				
			||||||
    page-break-after: avoid;
 | 
					 | 
				
			||||||
  }
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
@ -1,12 +1,3 @@
 | 
				
			|||||||
# Holy Moly
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
These notes are ancient but I like keeping them around because it reminds of
 | 
					 | 
				
			||||||
my college days when I didn't really know much :3
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
Not sure who will find value from these but here's some random tidbits of knowledge
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
# Everyone else
 | 
					# Everyone else
 | 
				
			||||||
 | 
					
 | 
				
			||||||
To some degree these notes are personal so there are a few mistakes that I just can't be bothered dealing with.
 | 
					To some degree these notes are personal so there are a few mistakes that I just can't be bothered dealing with.
 | 
				
			||||||
 | 
				
			|||||||
							
								
								
									
										24
									
								
								scripts/build-html.sh
									
									
									
									
									
										
										
										Executable file → Normal file
									
								
							
							
						
						
									
										24
									
								
								scripts/build-html.sh
									
									
									
									
									
										
										
										Executable file → Normal file
									
								
							@ -1,18 +1,10 @@
 | 
				
			|||||||
mkdir -p public/img
 | 
					#!/bin/sh
 | 
				
			||||||
cp gitlab-page/style.css public/style.css
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
md() {
 | 
					# Locations of important md files to build
 | 
				
			||||||
	pandoc -s --css style.css `ls -v $1`
 | 
					 | 
				
			||||||
}
 | 
					 | 
				
			||||||
 | 
					
 | 
				
			||||||
md "311/lec/*.md" 	> public/intro-to-networking-311.html
 | 
					lecture_dirs='311/lec/ 312/ 337/lec/ 363/lec/ 370/notes/ 412/'
 | 
				
			||||||
md "312/*.md" 		> public/network-security-concepts-312.html
 | 
					mkdir -p public
 | 
				
			||||||
 | 
					for d in $lecture_dirs;do
 | 
				
			||||||
md "337/lec/*.md" 	> public/computer-architecture-337.html
 | 
						echo $d;
 | 
				
			||||||
cp 337/img/* 		public/img/
 | 
						pandoc `ls --sort=version $d` -o "public/$d.html"
 | 
				
			||||||
 | 
					done
 | 
				
			||||||
md "363/lec/*.md" 	> public/intro-to-databases-363.html
 | 
					 | 
				
			||||||
md "370/notes/*.md" 	> public/advanced-algorithms-370.html
 | 
					 | 
				
			||||||
md "412/*.md"			> public/network-administration-412.html
 | 
					 | 
				
			||||||
 | 
					 | 
				
			||||||
md gitlab-page/index.md > public/index.html
 | 
					 | 
				
			||||||
 | 
				
			|||||||
@ -1,3 +0,0 @@
 | 
				
			|||||||
#!/bin/sh
 | 
					 | 
				
			||||||
cd public
 | 
					 | 
				
			||||||
python -m SimpleHTTPServer
 | 
					 | 
				
			||||||
		Loading…
	
		Reference in New Issue
	
	Block a user