[HECnet] Help to identify tap file format

Dear All, I found several pdp-11 tape image files on the net which have ".tap" suffix. It isn't well known simh/e11/tap/tpc tape images. Please help to identify which format they have. How such file can be converted to simh .tap or .tpc or how it can be used/mounted? Below is the beginning of hexdump of one of these files named "F77.TAP": $ hexdump -Cv F77.TAP 00000000 00 02 8c 02 00 00 00 04 02 00 50 00 00 04 03 00 |..........P.....| 00000010 00 02 00 04 04 00 50 00 00 04 05 00 50 00 00 06 |......P.....P...| 00000020 00 00 00 00 00 04 06 00 50 00 00 04 07 00 00 02 |........P.......| 00000030 00 04 08 00 00 02 00 04 09 00 50 00 00 04 0a 00 |..........P.....| 00000040 00 02 00 04 0b 00 50 00 00 04 0c 00 50 00 00 04 |......P.....P...| 00000050 0d 00 00 10 00 04 15 00 50 00 00 04 16 00 30 10 |........P.....0.| 00000060 00 04 1f 00 30 10 00 04 28 00 30 10 00 04 31 00 |....0...(.0...1.| 00000070 30 10 00 04 3a 00 30 10 00 04 43 00 30 10 00 04 |0...:.0...C.0...| 00000080 4c 00 30 10 00 04 55 00 30 10 00 04 5e 00 30 10 |L.0...U.0...^.0.| 00000090 00 04 67 00 30 10 00 04 70 00 30 10 00 04 79 00 |..g.0...p.0...y.| 000000a0 30 10 00 04 82 00 30 10 00 04 8b 00 30 10 00 04 |0.....0.....0...| 000000b0 94 00 30 10 00 04 9d 00 30 10 00 04 a6 00 30 10 |..0.....0.....0.| 000000c0 00 04 af 00 30 10 00 04 b8 00 30 10 00 04 c1 00 |....0.....0.....| 000000d0 30 10 00 04 ca 00 30 10 00 04 d3 00 30 10 00 04 |0.....0.....0...| 000000e0 dc 00 30 10 00 04 e5 00 30 10 00 04 ee 00 30 10 |..0.....0.....0.| 000000f0 00 04 f7 00 30 10 00 04 00 01 30 10 00 04 09 01 |....0.....0.....| 00000100 30 10 00 04 12 01 30 10 00 04 1b 01 30 10 00 04 |0.....0.....0...| 00000110 24 01 30 10 00 04 2d 01 30 10 00 04 36 01 30 10 |$.0...-.0...6.0.| 00000120 00 04 3f 01 30 10 00 04 48 01 30 10 00 04 51 01 |..?.0...H.0...Q.| 00000130 30 10 00 04 5a 01 30 10 00 04 63 01 30 10 00 04 |0...Z.0...c.0...| 00000140 6c 01 30 10 00 04 75 01 30 10 00 04 7e 01 30 10 |l.0...u.0...~.0.| 00000150 00 04 87 01 30 10 00 04 90 01 30 10 00 04 99 01 |....0.....0.....| 00000160 30 10 00 04 a2 01 30 10 00 04 ab 01 30 10 00 04 |0.....0.....0...| 00000170 b4 01 30 10 00 04 bd 01 30 10 00 04 c6 01 30 10 |..0.....0.....0.| 00000180 00 04 cf 01 30 10 00 04 d8 01 30 10 00 04 e1 01 |....0.....0.....| 00000190 30 10 00 04 ea 01 30 10 00 04 f3 01 30 10 00 04 |0.....0.....0...| 000001a0 fc 01 30 10 00 04 05 02 30 10 00 04 0e 02 30 10 |..0.....0.....0.| 000001b0 00 04 17 02 30 10 00 04 20 02 30 10 00 04 29 02 |....0... .0...).| 000001c0 30 10 00 04 32 02 30 10 00 04 3b 02 30 10 00 04 |0...2.0...;.0...| 000001d0 44 02 30 10 00 04 4d 02 30 10 00 04 56 02 30 10 |D.0...M.0...V.0.| 000001e0 00 04 5f 02 30 10 00 04 68 02 30 10 00 04 71 02 |.._.0...h.0...q.| 000001f0 30 10 00 04 7a 02 30 10 00 04 83 02 30 10 30 10 |0...z.0.....0.0.| 00000200 56 4f 4c 31 42 41 43 4b 55 50 20 20 20 20 20 20 |VOL1BACKUP | 00000210 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000220 20 20 20 20 20 44 25 42 31 31 31 31 30 30 31 30 | D%B11110010| 00000230 30 31 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |01 | 00000240 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 31 | 1| 00000250 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000260 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000270 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000280 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000290 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000002a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000002b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000002c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000002d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000002e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000002f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000300 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000310 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000320 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000330 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000340 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000350 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000360 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000370 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000380 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000390 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000003a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000003b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000003c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000003d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000003e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000003f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000400 a0 00 05 00 c6 15 00 02 c0 11 c0 65 1e 00 01 94 |...........e....| 00000410 03 03 f7 09 06 00 fb 01 05 00 00 00 5f 90 76 ff |............_.v.| 00000420 df 8b 74 ff fd 80 87 00 0d 0a 0a 20 20 20 2a 2a |..t........ **| 00000430 2a 54 48 49 53 20 56 4f 4c 55 4d 45 20 44 4f 45 |*THIS VOLUME DOE| 00000440 53 20 4e 4f 54 20 43 4f 4e 54 41 49 4e 20 41 20 |S NOT CONTAIN A | 00000450 48 41 52 44 57 41 52 45 20 42 4f 4f 54 41 42 4c |HARDWARE BOOTABL| 00000460 45 20 53 59 53 54 45 4d 20 2a 2a 2a 0d 0a 0a 00 |E SYSTEM ***....| 00000470 26 10 26 0a c1 15 ff 00 0e 64 c1 0a fd 02 81 15 |&.&......d......| 00000480 80 15 87 00 c1 1d 72 d5 f7 15 01 00 40 de 57 20 |......r..... at .W | 00000490 f9 63 07 83 b7 0a 36 de 57 20 f3 c9 02 83 b7 0a |.c....6.W ......| 000004a0 2c de f7 35 00 20 3e d5 0c 02 45 20 06 86 f7 35 |,..5. >...E ...5| 000004b0 00 01 84 dd 06 02 ce 89 04 01 f7 55 02 00 78 dd |...........U..x.| 000004c0 09 01 f7 15 06 00 ca dd f7 15 07 00 c6 dd f7 15 |................| 000004d0 08 00 c2 dd c0 1d f6 dd c0 0c 37 1c 84 10 b6 dd |..........7.....| 000004e0 00 0a c2 15 00 10 f7 09 0c 00 c2 0b 01 03 81 0a |................| 000004f0 77 10 9c d5 87 00 e6 10 c3 15 20 00 a6 10 02 0a |w......... .....| [...skipped...] Best regards. -- Fedor