This is a standard MS-DOS 3.30 (or later) MBR:
Code:
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00638000 FA 33 C0 8E D0 BC 00 7C 8B F4 50 07 50 1F FB FC ú3ÀŽÐ¼.|‹ôP.P.ûü
00638010 BF 00 06 B9 00 01 F2 A5 EA 1D 06 00 00 BE BE 07 ¿..¹..ò¥ê....¾¾.
00638020 B3 04 80 3C 80 74 0E 80 3C 00 75 1C 83 C6 10 FE ³.€<€t.€<.u.ƒÆ.þ
00638030 CB 75 EF CD 18 8B 14 8B 4C 02 8B EE 83 C6 10 FE ËuïÍ.‹.‹L.‹îƒÆ.þ
00638040 CB 74 1A 80 3C 00 74 F4 BE 8B 06 AC 3C 00 74 0B Ët.€<.tô¾‹.¬<.t.
00638050 56 BB 07 00 B4 0E CD 10 5E EB F0 EB FE BF 05 00 V»..´.Í.^ëðëþ¿..
00638060 BB 00 7C B8 01 02 57 CD 13 5F 73 0C 33 C0 CD 13 ».|¸..WÍ._s.3ÀÍ.
00638070 4F 75 ED BE A3 06 EB D3 BE C2 06 BF FE 7D 81 3D Ouí¾£.ëÓ¾Â.¿þ}.=
00638080 55 AA 75 C7 8B F5 EA 00 7C 00 00 49 6E 76 61 6C UªuÇ‹õê.|..Inval
00638090 69 64 20 70 61 72 74 69 74 69 6F 6E 20 74 61 62 id partition tab
006380A0 6C 65 00 45 72 72 6F 72 20 6C 6F 61 64 69 6E 67 le.Error loading
006380B0 20 6F 70 65 72 61 74 69 6E 67 20 73 79 73 74 65 operating syste
006380C0 6D 00 4D 69 73 73 69 6E 67 20 6F 70 65 72 61 74 m.Missing operat
006380D0 69 6E 67 20 73 79 73 74 65 6D 00 00 00 00 00 00 ing system......
006380E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
........
006381A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
006381B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 01 ..............€.
006381C0 01 00 04 0F C2 E5 02 00 00 00 BE 7C 00 00 00 00 ....Âå....¾|....
006381D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
006381E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
006381F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 AA ..............Uª
There is a single "DOS 3.0+ 16-bit FAT" partition (type 04) beginning at sector 2 with a size of 0x7CBE sectors.
http://thestarman.pcministry.com/asm/mbr/STDMBR.htmhttps://www.win.tue.nl/~aeb/partitions/ ... pes-1.htmlHere is the MS-DOS 5.0 FAT16 boot sector:
Code:
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00638400 EB 3C 90 4D 53 44 4F 53 35 2E 30 00 02 04 01 00 ë<.MSDOS5.0.....
00638410 02 F0 00 BE 7C F8 20 00 02 00 10 00 02 00 00 00 .ð.¾|ø .........
00638420 00 00 00 00 80 00 29 00 00 00 00 20 20 20 20 20 ....€.)....
00638430 20 20 20 20 20 20 46 41 54 31 36 20 20 20 FA 33 FAT16 ú3
00638440 C0 8E D0 BC 00 7C 16 07 BB 78 00 36 C5 37 1E 56 ÀŽÐ¼.|..»x.6Å7.V
00638450 16 53 BF 3E 7C B9 0B 00 FC F3 A4 06 1F C6 45 FE .S¿>|¹..üó¤..ÆEþ
00638460 0F 8B 0E 18 7C 88 4D F9 89 47 02 C7 07 3E 7C FB .‹..|ˆMù‰G.Ç.>|û
00638470 CD 13 72 79 33 C0 39 06 13 7C 74 08 8B 0E 13 7C Í.ry3À9..|t.‹..|
00638480 89 0E 20 7C A0 10 7C F7 26 16 7C 03 06 1C 7C 13 ‰. | .|÷&.|...|.
00638490 16 1E 7C 03 06 0E 7C 83 D2 00 A3 50 7C 89 16 52 ..|...|ƒÒ.£P|‰.R
006384A0 7C A3 49 7C 89 16 4B 7C B8 20 00 F7 26 11 7C 8B |£I|‰.K|¸ .÷&.|‹
006384B0 1E 0B 7C 03 C3 48 F7 F3 01 06 49 7C 83 16 4B 7C ..|.ÃH÷ó..I|ƒ.K|
006384C0 00 BB 00 05 8B 16 52 7C A1 50 7C E8 92 00 72 1D .»..‹.R|¡P|è’.r.
006384D0 B0 01 E8 AC 00 72 16 8B FB B9 0B 00 BE E6 7D F3 °.è¬.r.‹û¹..¾æ}ó
006384E0 A6 75 0A 8D 7F 20 B9 0B 00 F3 A6 74 18 BE 9E 7D ¦u... ¹..ó¦t.¾ž}
006384F0 E8 5F 00 33 C0 CD 16 5E 1F 8F 04 8F 44 02 CD 19 è_.3ÀÍ.^....D.Í.
00638500 58 58 58 EB E8 8B 47 1A 48 48 8A 1E 0D 7C 32 FF XXXëè‹G.HHŠ..|2ÿ
00638510 F7 E3 03 06 49 7C 13 16 4B 7C BB 00 07 B9 03 00 ÷ã..I|..K|»..¹..
00638520 50 52 51 E8 3A 00 72 D8 B0 01 E8 54 00 59 5A 58 PRQè:.rØ°.èT.YZX
00638530 72 BB 05 01 00 83 D2 00 03 1E 0B 7C E2 E2 8A 2E r»...ƒÒ....|ââŠ.
00638540 15 7C 8A 16 24 7C 8B 1E 49 7C A1 4B 7C EA 00 00 .|Š.$|‹.I|¡K|ê..
00638550 70 00 AC 0A C0 74 29 B4 0E BB 07 00 CD 10 EB F2 p.¬.Àt)´.»..Í.ëò
00638560 3B 16 18 7C 73 19 F7 36 18 7C FE C2 88 16 4F 7C ;..|s.÷6.|þˆ.O|
00638570 33 D2 F7 36 1A 7C 88 16 25 7C A3 4D 7C F8 C3 F9 3Ò÷6.|ˆ.%|£M|øÃù
00638580 C3 B4 02 8B 16 4D 7C B1 06 D2 E6 0A 36 4F 7C 8B ô.‹.M|±.Òæ.6O|‹
00638590 CA 86 E9 8A 16 24 7C 8A 36 25 7C CD 13 C3 0D 0A ʆéŠ.$|Š6%|Í.Ã..
006385A0 4E 6F 6E 2D 53 79 73 74 65 6D 20 64 69 73 6B 20 Non-System disk
006385B0 6F 72 20 64 69 73 6B 20 65 72 72 6F 72 0D 0A 52 or disk error..R
006385C0 65 70 6C 61 63 65 20 61 6E 64 20 70 72 65 73 73 eplace and press
006385D0 20 61 6E 79 20 6B 65 79 20 77 68 65 6E 20 72 65 any key when re
006385E0 61 64 79 0D 0A 00 49 4F 20 20 20 20 20 20 53 59 ady...IO SY
006385F0 53 4D 53 44 4F 53 20 20 20 53 59 53 00 00 55 AA SMSDOS SYS..Uª
The size of the volume matches the partition table (0x7CBE).
The cluster size is 4 sectors at 512 bytes per sector.
There are 2 FATs, each comprising 0x20 (32) sectors.
The number of 32-byte root directory entries is 0xF0 (240).
https://staff.washington.edu/dittrich/m ... gen103.pdfOne copy of the FAT is at 0x638600 - 0x63BFFF, the other is at 0xAF4600 - 0xAF7FFF. Only the first 29 of 32 sectors appear to be present in each block, the remaining 3 sectors are elsewhere. The two FAT copies are identical.
Searching for "NK <6 spaces> BIN" finds several directory entries for NK.BIN.
Code:
Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
002E6C80 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
002E6C90 00 00 00 00 00 00 14 5D 4E 2E 00 00 00 00 00 00 .......]N.......
00772C80 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
00772C90 00 00 00 00 00 00 59 7D 7C 2C 8D 01 13 57 48 00 ......Y}|,...WH.
00776C80 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
00776C90 00 00 00 00 00 00 59 7D 7C 2C 8D 01 13 57 48 00 ......Y}|,...WH.
0077AC80 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
0077AC90 00 00 00 00 00 00 59 7D 7C 2C 8D 01 13 57 48 00 ......Y}|,...WH.
0083EC80 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
0083EC90 00 00 00 00 00 00 59 7D 7C 2C 8D 01 13 57 48 00 ......Y}|,...WH.
00842C80 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
00842C90 00 00 00 00 00 00 59 7D 7C 2C 8D 01 13 57 48 00 ......Y}|,...WH.
00FCD480 4E 4B 20 20 20 20 20 20 42 49 4E 20 00 00 00 00 NK BIN ....
00FCD490 00 00 00 00 00 00 59 7D 7C 2C EA 01 13 57 48 00 ......Y}|,ê..WH.
An analysis of the FATs suggests that the actual starting cluster for NK.BIN is 0x1EA (not 0x18D) and the last cluster is 0xAF4.
The size of the file is 0x90B clusters (0xAF4 - 0x1EA + 1 = 0x90B = 2315).
The size in bytes (from the file's directory entry) is 0x485713 (4740883 bytes).
The difference between the two numbers is less than 1 cluster, so clearly the file is not fragmented.
0x90B x 2048 - 4740883 = 237 bytes
So, in short, the NK.BIN file appears to be intact, but you are still left with the task of piecing it together.