Texas Instruments TI-83 PLUS - Manual (Page 627)

TI-83 Plus Memory and Variable Management 624
Each variable that you archive is stored in the first empty block large
enough to hold it.
This process continues to the end of the last sector. Depending on the
size of individual variables, the empty blocks may account for a
significant amount of space. Garbage collection occurs when the
variable you are archiving is larger than any empty block.
Sector 1
Sector 2
Sector 3
variable A
variable B
variable C
Empty
block
variable D
Depending on its size,
variable D is stored in
one of these locations.