vault backup: 2022-07-14 20:11:09

content/notes/ASCII.md

@@ -0,0 +1,28 @@
+---
+title: "ASCII"
+aliases: 
+tags: 
+- cosc204
+---
+
+# ASCII Character Code
+![ascii code](https://i.imgur.com/NbBtm1v.png)
+
+1. The computer uses ch as a integer index into a pre-existing table 
+2. the computer screen is made up of a thousand little dots called pixels. theyre in a rectangular grid like a table.a
+
+- [ascii code example](https://i.imgur.com/9uvKRVo.png)
+
+- There are several tables that describe what to draw
+	- fonts describe how to draw them
+- ASCII (american standard code for information) describes what should be drawn for Roman (english like) alphabets
+- e.g.,
+	- A 1000001 (65)
+	- B 1100001 (97)
+	- 9 0111001 (57)
+- There are only a few letter numbers and punctuation marks. The remaining ASCII code are non-printing and have other meaning (line feed, for feed, tab etcc)
+- ASCII characters are stored using 7-bits
+	- so there are 128 (2^7) possible characters
+	- stored as a byte with the 8th bit set to zero
+	- For sorting purposes characters are compared on their numeric value (called the *collating sequence*)
+	- 'A' is before 'Z' but 'a' is after 'Z'!

content/notes/cosc-204.md

@@ -14,10 +14,13 @@ tags:
 
 # Notes
 By completion of this paper students are expected to:
+- [ASCII](notes/ASCII.md)
+- [unicode](notes/unicode.md)
+- [digital-data](notes/digital-data.md)
+- [memory](notes/memory.md)
 
 ## Hardware
 - Understand how programs are executed on computer hardware
-- [memory](notes/memory.md)
 
 
 ## Assembly

content/notes/digital-data.md

@@ -39,3 +39,15 @@ Data is stored in [memory](notes/memory.md)
 - [amount of bits for different devices](https://i.imgur.com/nHrz1zX.png)
 
 # Characters
+- A written symbol.
+- In english are represented as a single byte, (other languages use 2 bytes or more)
+- e.g., [different types of characters](https://i.imgur.com/DBLVhw8.png)
+
+- characters are joined together to make human readable numbers and words
+
+- `char ch` 
+- ch is a variable name (identifier) 
+- used to label a location in the computer's memory where a byte is stored
+- when the code is compile, the name is assigned an address, in memory. The meaning of that data depends on how a human interprets it. it might be small integer, or a character, or a color etc.d
+
+- each byte represents a number which maps to a character using either [[unic]]

content/notes/unicode.md

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+---
+title: "unicode"
+aliases: 
+tags: 
+- cosc204
+---
+
+## Unicode
+![unicode](https://i.imgur.com/GEtVItW.png)
+
+- Other non roman languages
+	- greek, arabic, chinese, hebrew, japanese, thai etc.
+	- atrology symbols
+	- emoji etc
+- Unicode
+	- developed by the Unicode Consortium
+	- coordinated with ISO/IEC 10646
+	- a 21-bit code with 144,697 characters from 159 scripts
+	- unicode maps from character numbers (code points) into glyphs (graphical representations)
+	- Some(many) are reserved