Updated SD section, added jenkinsfile

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 docs/.vitepress/dist
-.vscode
+.vscode
+*.DS_Store*

Jenkinsfile

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+pipeline {
+    agent any
+    stages {
+        stage('Build') {
+            steps {
+                echo 'Building'
+            }
+        }
+    }
+}

docs/interview/sd/basics.md

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+# Basics of the Internet
+
+## Client-Server Model
+
+The internet is based on the client-server model.  Servers are processes that provides services to clients, and clients are processes which request things from the servers.  These machines find each other using their **IP addresses**, which are 4 numbers from 0 to 255 in a.b.c.d format, and communicate through **ports**.  A **DNS**, or Domain Name Server, links domain names to IP addresses.
+
+::: details
+Notable IP Addresses include 127.0.0.1 or localhost which is your own machine and 
+192.168.c.d are machines on your local network.  Notable ports include 22 (ssh), 443 (https), 
+80 (http), and 53 (DNS lookup).
+:::
+
+## Protocols
+
+The above method of communication is known as Internet Protocol.  There are additional protocols built on top of IP.
+
+### TCP
+
+TCP allows for ordered, reliable data delivery between machines through connections.  This also exposes **sockets** which allow applications to stream data through an open connection.
+
+### HTTP
+
+HTTP (HyperText Transfer Protocol) is implemented on top of TCP.  This is the request-response model.  Requests typically have a method, headers, and a body as well as origin information, and the request typically has a status and some kind of data.

docs/interview/sd/latency.md

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+# Latency
+
+Latency describes the time it takes for a machine to perform a certain operation.  Every method of retrieving information has different time costs.  A general rule of thumb:
+
+- Reading 1MB from RAM - 0.25ms
+- Reading 1MB from SSD - 1ms
+- Transfer 1MB over network - 10ms
+- Reading 1MB from HDD - 20ms
+- Intercontinental round-trip - 150ms
+
+## Throughput
+
+While latency measures the time operations take, throughput describes the number of operations that can be processed in a given amount of time, such as requests per second.

docs/interview/sidebar.json

@@ -23,6 +23,8 @@
     {
         "text": "System Design",
         "items": [
+            {"text": "Basics of the Internet", "link": "/interview/sd/basics"},
+            {"text": "Latency", "link": "/interview/sd/latency"},
             {"text": "Scaling", "link": "/interview/sd/scaling"}
         ]
     }