A New Deal program to help long-term families to have home. Tho program lowered down-payment for homes down from \(50\%\) down to only \(<10\%\). This is part of Roosevelt’s New Deal to lower interest rates and increased national home ownership rates. This could have been attributed to programs to stabilize home prices. This specifically helped white families: favoured single-family homes.

The Federal Project Number One is a branch of projects under the WPA which created opportunities for writers, musicians, artists, writers, etc.

A field is a special set.

constituents

• distinct elements of at least \(0\) and \(1\)
• operations of addition and multiplication

requirements

• closed
• commutativity
• associativity
• identities (both additive and multiplicative)
• inverses (both additive and multiplicative)
• distribution

Therefore, \(\mathbb{R}\) is a field, and so is \(\mathbb{C}\) (which we proved in properties of complex arithmetic).

additional information

Main difference between group: there is one operation is group, a field has two operations.

Store files strided across the disk, and store the blocks which the file uses as a list of block ids. We can then jump on that block IDs and then jump to there

The filesystem is the only thing that can store anything across power offs.

disk

Unlike memory, its “sector-addressable”: you cannot read or write individual bytes. The disk is divided into sectors, which you have to wholesale read and write.

seeking

Because disks are mostly moving, reading and writing requires seeking: to wait until the platter go under the arm and read.

filesystems are designed to minimize the seek time.

functionality

• creating
• looknig up
• reading: sequential + random file access; access either all of a file or a part of the file
• editing
• creating folders

main challenges

• disk space management: minimize seeks, sharing space, efficient use of disk
• naming: how do users name files
• reliability: surviving OS crashes and hardware failures
• protection: isolation between users, controlled sharing

block

a block is a group of one or more sectors, which issued to abstract away chunks of sectors.