Cluster size in file systems

	A	B	C	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	U	V	W	X	Y	Z	AA	AB	AC	AD	AE	AF	AG	AH	AI	AJ	AK	AL
1	This chart calculates the filesystem layout and capacity of an exFAT formatted drive.
2	Assumes GPT (GUID Partition Table)
3	Assumes single partition spanning the entire volume (multiple partitions merely have to account for the difference in partitioning overhead vs filesystem overhead and correctly follow partition boundaries when making calculations).
4	The most convenient unit of data to work with is a "sector". Units are noted in [square brackets]. Probably all flash drives have a logical sector size of 512 bytes. Remember what your high school physics teacher told you about keeping your units straight. It's important!
5	N.B. Flash storage devices, SSDs including, will often have larger sectors (called pages) physically, but will happily lie about it to the OS. Most spinning rust drives will instead correctly report 4K physical sectors, but will emulate 512 bytes to the OS for the benefit of backwards compatibility.
6	exFAT specification: https://learn.microsoft.com/en-us/windows/win32/fileio/exfat-specification
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8	Hardware (sort of)
9	512	sector size [bytes]
10	30851071	Total drive sectors																			device and formatter dependent parameters
11					[KiB]	[sectors]	[clusters]	[bytes]	[sectors]	[KiB]	[clusters]	[KiB]	[KiB]	[bytes]	[sectors]	[clusters]	[clusters]	[KiB]		[sectors]	[sectors]	[sectors]	[sectors]	[sectors]	[sectors]											[KiB]
12	34	First use LBA		2ⁿ	cluster size	cluster size	data	data	wasted space	wasted space	metadata	metadata	total "wasted" space	bitmap	bitmap	bitmap	Up-case table	offset overhead	frac clusters	available for cluster heap	cluster heap offset [sectors]	min cluster heap offset	FAT offset	FAT len	min FAT len	FAT len factors		ceil to even values						cluster heap offset dec2bin	Number of files above which a lower cluster size becomes more efficient.	Avg wasted space per file
13	30851038	Last use LBA		-1	0.5	1	30605278	15669902336	0	0	7486	3743	125599	3825660	7472	7472	12	121856	30605278	30605278	243712	243056	2048	241008	239104	2*4+3+5021	15063	15064	2*3+7+269	1884	472	60	16	111011100000000000		0.25
14				0	1	2	15363055	15731768320	0	0	1884	1884	63324	1920382	3751	1876	6	61440	15363055	30726110	122880	122552	2048	120504	120024	2*3+3+5021	15063	15064	2*3+7+269	1884	472	60	16	011110000000000000	249100	0.5
15	2048	First LBA	The only values we care about.	1	2	4	7696375	15762176000	2	1	475	950	32695	962047	1879	470	3	31744	7696375.5	30785502	63488	62300	2048	60252	60128	2*2+3+5021	15063	15064	2*3+7+269	1884	472	60	16	001111100000000000	61258	1
16	30851038	Last LBA		2	4	8	3852027	15777902592	6	3	122	488	16875	481504	941	118	2	16384	3852027.75	30816222	32768	32176	2048	30128	30094	2*4+7+269	1883	1884	2*2+3+157	472	60	16		001000000000000000	15820	2
17				3	8	16	1926909	15785238528	14	7	33	264	9487	240864	471	30	1	9216	1926909.875	30830558	18432	17120	2048	15072	15054	2*5+3+157	471	472	2*3+59	60	16			000100100000000000	3694	4
18	These values are located in the boot sector.			4	16	32	963710	15789424640	30	15	11	176	5311	120464	236	8	1	5120	963710.9375	30838750	10240	9600	2048	7552	7529	2*7+59	59	60	2*2+3+5	16				000010100000000000	1044	8
19	2048	partition offset [sectors]		5	32	64	481919	15791521792	30	15	5	160	3247	60240	118	2	1	3072	481919.4688	30842846	6144	5824	2048	3776	3765	2*6+59	59	60	2*2+3+5	16				000001100000000000	258	16
20	4096	FAT offset		6	64	128	240975	15792537600	94	47	4	256	2351	30122	59	1	1	2048	240975.7344	30844894	4096	3968	2048	1920	1883	2*7+3+5	15	16						000001000000000000	56	32
21	4096			7	128	256	120487	15792472064	222	111	4	512	2671	15061	30	1	1	2048	120487.8672	30844894	4096	3072	2048	1024	942										-10	64
22	6144	partitioning overhead [sectors]		8	256	512	60243	15792340992	478	239	4	1024	3311	7531	15	1	1	2048	60243.93359	30844894	4096	2560	2048	512	471										-10	128
23				9	512	1024	30121	15792078848	990	495	4	2048	4591	3766	8	1	1	2048	30121.9668	30844894	4096	3072	2048	1024	236										-10	256
24	30844894	sectors available for cluster heap		10	1024	2048	15060	15791554560	2014	1007	4	4096	7151	1883	4	1	1	2048	15060.9834	30844894	4096	4096	2048	2048	118										-10	512
25				11	2048	4096	7529	15789457408	2014	1007	4	8192	13295	942	2	1	1	4096	7529.491699	30840798	8192	8192	4096	4096	59										-12	1024
26				12	4096	8192	3763	15783165952	6110	3055	4	16384	27631	471	1	1	1	8192	3763.74585	30832606	16384	16384	8192	8192	30										-14	2048
27	5836	Up-case table [bytes]		13	8192	16384	1880	15770583040	14302	7151	4	32768	56303	235	1	1	1	16384	1880.872925	30816222	32768	32768	16384	16384	15										-14	4096
28	12	Up-case table [sectors]		14	16384	32768	939	15753805824	14302	7151	4	65536	105455	118	1	1	1	32768	939.4364624	30783454	65536	65536	32768	32768	8										-12	8192
29				15	32768	65536	468	15703474176	47070	23535	4	131072	220143	59	1	1	1	65536	468.7182312	30717918	131072	131072	65536	65536	4
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32					64	Optimal cluster size for maximizing capacity.																			Goes x2, but then every once in a while fits just a little bit shy of x2
33	30851038	16 gig flash stick																							May involve bitwise ops.
34	3907022840	2TB drive																							May be tied to cl heap offset.
35	241696759	128-ish gig
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