answer questions

Author: brownsarahm

notes/2025-09-30.md

@@ -163,7 +163,7 @@ So in broader context, the [git visual cheatsheet](https://ndpsoftware.com/git-c
 +++{"lesson_part": "main","type":"heading"}
 
 
-
+(setsofcommands)=
 ## Git has two sets of commands
 
 - Porcelain: the user friendly VCS
@@ -191,13 +191,13 @@ a lot of programming is *designing* abstractions, to get good at making somethin
 +++{"lesson_part": "main"}
 
 
-We have so far used git as a version control system.  A version control system, in general, will have operations like commit, push, pull, clone.  These may work differently under the hood or be called different things, but those are what something needs to have in order to keep track of different versions.
+We have so far used git as a version control system, using the {term}`porcelain` commands.  A version control system, in general, will have operations like commit, push, pull, clone.  These may work differently under the hood or be called different things, but those are what something needs to have in order to keep track of different versions.
 
 
 
 +++{"lesson_part": "main"}
 
-The plumbing commands reveal the *way* that git performs version control operations.  This means, they implement the git file system operations for the git version control system.  
+The {term}`plumbing` commands reveal the *way* that git performs version control operations.  This means, they implement the git file system operations for the git version control system.  
 
 
 +++{"lesson_part": "main"}
@@ -1070,4 +1070,42 @@ Append the contents of one of your trees or commits and one blob or tree inside
 
 That is, paste the result of you tracing through your own repo. 
 
-## Questions After Today's Class 
+## Questions After Today's Class 
+
+
+### How will we apply this information to the course?
+
+Today we saw an example of how abstractions can work (or not quite work, since git is a leaky abstraction). 
+
+Seeing how git works *as* a file system also starts to build up your knowledge of what kinds of operations *any* file system needs to implement
+
+### Is there a benefit to working with git at a lower level?
+
+It is mostly helpful for understanding how git works so that you can understand how the more advanced features work, which can save you a lot of time. 
+
+We studied it primarily to see how *a* file system works. 
+
+It could, however, be useful if you were building a developer tool, or you wanted to contribute to git itself [see gitgitgadget for how](https://gitgitgadget.github.io/)
+
+### Is it possible to check the oldest commit using cat .git/HEAD
+
+You coudl trace backwards, like parsing through a linked list: 
+- first `cat .git/HEAD`
+- then `cat` the file that tells you about
+- then use `git cat-file -p` on the hash from the file above
+- then use `git cat-file -p` hash of the parent commit
+- repeat above until there is no parent commit. 
+
+
+### Can we configure Git to use a stronger hashing algorithm?
+
+It looks like you can actually, from the [transition plan's detailed design](https://git-scm.com/docs/hash-function-transition#_detailed_design) that they have implemented it. However, it appears [github does not support that](https://github.com/orgs/community/discussions/12490), but [gitlab does at least partially](https://about.gitlab.com/blog/sha256-support-in-gitaly/)
+
+::::::{attention}
+this is a good topic for an explore badge. 
+::::::::
+
+
+### If we are seeing a command for the first time, how do we know if it is porcelain or plumbing?
+
+You can use the [definitions](setsofcommands) and what the command does. 

resources/glossary.md

@@ -162,10 +162,14 @@ parent
 path
 :  the "location" of a file or folder(directory) in a computer
 
+plumbing
+:  (git command type) the internal workings- a toolkit for a VCS
 
 pointer
 :  a variable that stores the address of another variable
 
+porcelain
+:  (git command type) the user friendly VCS
 
 pull (changes from a repository)
 :  download changes from a remote repository and update the local repository with these changes.