ASCIIZ	A NUL-terminated ASCII string
BPB	BIOS Parameter Block
CDS	Current Directory Structure
DPB	Drive Parameter Block
FAT	File Allocation Table
FCB	File Control Block
FS	File System
HMA	High Memory Area
IFS	Installable File System
LoL	List of Lists
LRU	Least Recently Used
MCB	Memory Control Block
PSP	Program Segment Prefix
SFT	System File Table
UMB	Upper Memory Block
XMS	eXtended Memory Specification


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BPB media ID
	0xf0 =  3"/1.44M 2 sides, 18 sectors
		3"/2.88M 2 sides, 36 sectors
		5"/1.2M  2 sides, 15 sectors
	0xf8 =  fixed disk
	0xf9 =  3"/720K  2 sides,  9 sectors, 80 tracks
		5"/1.2M  2 sides, 15 sectors, 80 tracks
	0xfa =  HP 200LX
	0xfb =  3"/640K  2 sides,  8 sectors, 80 tracks
	0xfc =  5"/180K  1 sides,  9 sectors, 40 tracks
	0xfd =  5"/360K  2 sides,  9 sectors, 40 tracks
	0xfe =  5"/160K  1 sides,  8 sectors, 40 tracks
	0xff =  5"/320K  2 sides,  8 sectors, 40 tracks
