Merge pull request #19 from introcompsys/agc

info about AGC

Author: brownsarahm

notes/2023-04-18.md

@@ -185,7 +185,15 @@ we eventually need clocks to time things and synchronize things to like know whe
 In 1945 we get a draft of a general template. This is basically what we use today.  
 
 
+## Apollo Guidance Computer (AGC)
 
+The AGC was the onboard computer for NASA's Apollo programs. It provided navigation for the control capsule as well as controlled the spacecraft during moon landings. The AGC had only 72KB of fixed memory (589,824 bits). Unlike many early computers, the software for the AGC was stored in its memory and was not physically built into its hardware's circuitry.
+
+Additionally, this computer had RAM, which was memory that could be changed by the computer while it was running. This memory had a capacity of only 4KB (32,768 bits), which was still enough to store all the data needed to perform all calculations necessary for the missions. The AGC could be controlled by the astronauts in the command capsule by sending commands via a numeric keyboard. Its user interface consisted of a simple screen and a set of status lights that relayed information to the astronauts.
+
+This computer is very similar to how modern computers work in the sense that it can keep data in its fixed memory even while the computer is off.
+
+To learn more about the AGC and how it worked, you can view [this](https://bigthink.com/hard-science/phone-computer-moon-landing/) article, or view the [official NASA public docs](https://history.nasa.gov/computers/Ch2-5.html) on it.
 
 ## Storage