CD-ROM Read After a Pause

Replays a game's two-part read sequence and records which sectors arrive and when.

This is an old revision of this page, as edited by RemmyLee at 05:11, 23 October 2026. Edit this revision | Latest revision

Overview

The probe replays the read sequence of ATV - Quad Power Racing with that game's disc in the drive. It sets mode A0h, which selects double speed and whole 924h-byte sectors. It reads 8 sectors from 15:24:35, pauses, then sets 15:24:43 and reads until 16 sectors have arrived, another interrupt comes, or 15 seconds pass.¹

Each sector's whole 924h bytes are taken from the data FIFO and its 4-byte header is logged. Root counter 2 counts system clock cycles divided by 8, and every interrupt is polled. The probe makes three runs.¹

Results

In all three runs the second read delivered 16 sectors in order from 15:24:43 to 15:24:58 with no error. Its first INT1 came 68.4, 68.6 and 75.1 ms after ReadN.¹

The first read's first sector came after 1172 ms in run 1 and after 66.3 to 66.5 ms in runs 2 and 3.¹

Pause answered INT2 about 85 ms after the command in every run.¹

Runs

Run 5501a-link on 16 October 2026

Raw output: ATVSEQ.txt

ATVSEQ.txt:

ATVSEQ start
ATVSEQ 1 1 Setmode t 3919 INT3 12
ATVSEQ 1 1 Setloc t 6374 INT3 12
ATVSEQ 1 1 ReadN t 7465 INT3 12
ATVSEQ 1 1 INT1-1 t 4961260 INT1 32 hdr 15 24 35 02
ATVSEQ 1 1 INT1-2 t 4987456 INT1 32 hdr 15 24 36 02
ATVSEQ 1 1 INT1-3 t 5018478 INT1 32 hdr 15 24 37 02
ATVSEQ 1 1 INT1-4 t 5044554 INT1 32 hdr 15 24 38 02
ATVSEQ 1 1 INT1-5 t 5071959 INT1 32 hdr 15 24 39 02
ATVSEQ 1 1 INT1-6 t 5100807 INT1 32 hdr 15 24 40 02
ATVSEQ 1 1 INT1-7 t 5128697 INT1 32 hdr 15 24 41 02
ATVSEQ 1 1 INT1-8 t 5157006 INT1 32 hdr 15 24 42 02
ATVSEQ 1 1 Pause t 12867 INT3 32
ATVSEQ 1 1 Pause-2 t 362179 INT2 12
ATVSEQ 1 2 Setloc t 8157 INT3 12
ATVSEQ 1 2 ReadN t 6224 INT3 12
ATVSEQ 1 2 INT1-1 t 289577 INT1 32 hdr 15 24 43 02
ATVSEQ 1 2 INT1-2 t 316481 INT1 32 hdr 15 24 44 02
ATVSEQ 1 2 INT1-3 t 345782 INT1 32 hdr 15 24 45 02
ATVSEQ 1 2 INT1-4 t 373657 INT1 32 hdr 15 24 46 02
ATVSEQ 1 2 INT1-5 t 401545 INT1 32 hdr 15 24 47 02
ATVSEQ 1 2 INT1-6 t 429179 INT1 32 hdr 15 24 48 02
ATVSEQ 1 2 INT1-7 t 457314 INT1 32 hdr 15 24 49 02
ATVSEQ 1 2 INT1-8 t 486452 INT1 32 hdr 15 24 50 02
ATVSEQ 1 2 INT1-9 t 513817 INT1 32 hdr 15 24 51 02
ATVSEQ 1 2 INT1-10 t 542761 INT1 32 hdr 15 24 52 02
ATVSEQ 1 2 INT1-11 t 570774 INT1 32 hdr 15 24 53 02
ATVSEQ 1 2 INT1-12 t 599828 INT1 32 hdr 15 24 54 02
ATVSEQ 1 2 INT1-13 t 627515 INT1 32 hdr 15 24 55 02
ATVSEQ 1 2 INT1-14 t 655472 INT1 32 hdr 15 24 56 02
ATVSEQ 1 2 INT1-15 t 685817 INT1 32 hdr 15 24 57 02
ATVSEQ 1 2 INT1-16 t 711995 INT1 32 hdr 15 24 58 02
ATVSEQ 1 2 Pause t 12483 INT3 32
ATVSEQ 1 2 Pause-2 t 362003 INT2 12
ATVSEQ 2 1 Setmode t 12055 INT3 12
ATVSEQ 2 1 Setloc t 8141 INT3 12
ATVSEQ 2 1 ReadN t 5739 INT3 12
ATVSEQ 2 1 INT1-1 t 281524 INT1 32 hdr 15 24 35 02
ATVSEQ 2 1 INT1-2 t 307600 INT1 32 hdr 15 24 36 02
ATVSEQ 2 1 INT1-3 t 338906 INT1 32 hdr 15 24 37 02
ATVSEQ 2 1 INT1-4 t 363924 INT1 32 hdr 15 24 38 02
ATVSEQ 2 1 INT1-5 t 392824 INT1 32 hdr 15 24 39 02
ATVSEQ 2 1 INT1-6 t 420595 INT1 32 hdr 15 24 40 02
ATVSEQ 2 1 INT1-7 t 451791 INT1 32 hdr 15 24 41 02
ATVSEQ 2 1 INT1-8 t 477919 INT1 32 hdr 15 24 42 02
ATVSEQ 2 1 Pause t 12641 INT3 32
ATVSEQ 2 1 Pause-2 t 362024 INT2 12
ATVSEQ 2 2 Setloc t 7894 INT3 12
ATVSEQ 2 2 ReadN t 4946 INT3 12
ATVSEQ 2 2 INT1-1 t 290358 INT1 32 hdr 15 24 43 02
ATVSEQ 2 2 INT1-2 t 317293 INT1 32 hdr 15 24 44 02
ATVSEQ 2 2 INT1-3 t 345602 INT1 32 hdr 15 24 45 02
ATVSEQ 2 2 INT1-4 t 373558 INT1 32 hdr 15 24 46 02
ATVSEQ 2 2 INT1-5 t 403144 INT1 32 hdr 15 24 47 02
ATVSEQ 2 2 INT1-6 t 431154 INT1 32 hdr 15 24 48 02
ATVSEQ 2 2 INT1-7 t 458360 INT1 32 hdr 15 24 49 02
ATVSEQ 2 2 INT1-8 t 486992 INT1 32 hdr 15 24 50 02
ATVSEQ 2 2 INT1-9 t 517574 INT1 32 hdr 15 24 51 02
ATVSEQ 2 2 INT1-10 t 542754 INT1 32 hdr 15 24 52 02
ATVSEQ 2 2 INT1-11 t 570890 INT1 32 hdr 15 24 53 02
ATVSEQ 2 2 INT1-12 t 599821 INT1 32 hdr 15 24 54 02
ATVSEQ 2 2 INT1-13 t 627453 INT1 32 hdr 15 24 55 02
ATVSEQ 2 2 INT1-14 t 655741 INT1 32 hdr 15 24 56 02
ATVSEQ 2 2 INT1-15 t 684669 INT1 32 hdr 15 24 57 02
ATVSEQ 2 2 INT1-16 t 712226 INT1 32 hdr 15 24 58 02
ATVSEQ 2 2 Pause t 10538 INT3 32
ATVSEQ 2 2 Pause-2 t 362684 INT2 12
ATVSEQ 3 1 Setmode t 12359 INT3 12
ATVSEQ 3 1 Setloc t 8133 INT3 12
ATVSEQ 3 1 ReadN t 5504 INT3 12
ATVSEQ 3 1 INT1-1 t 280667 INT1 32 hdr 15 24 35 02
ATVSEQ 3 1 INT1-2 t 306990 INT1 32 hdr 15 24 36 02
ATVSEQ 3 1 INT1-3 t 337504 INT1 32 hdr 15 24 37 02
ATVSEQ 3 1 INT1-4 t 363570 INT1 32 hdr 15 24 38 02
ATVSEQ 3 1 INT1-5 t 391723 INT1 32 hdr 15 24 39 02
ATVSEQ 3 1 INT1-6 t 421876 INT1 32 hdr 15 24 40 02
ATVSEQ 3 1 INT1-7 t 448006 INT1 32 hdr 15 24 41 02
ATVSEQ 3 1 INT1-8 t 476854 INT1 32 hdr 15 24 42 02
ATVSEQ 3 1 Pause t 4110 INT3 32
ATVSEQ 3 1 Pause-2 t 334021 INT2 12
ATVSEQ 3 2 Setloc t 7976 INT3 12
ATVSEQ 3 2 ReadN t 5015 INT3 12
ATVSEQ 3 2 INT1-1 t 317912 INT1 32 hdr 15 24 43 02
ATVSEQ 3 2 INT1-2 t 347255 INT1 32 hdr 15 24 44 02
ATVSEQ 3 2 INT1-3 t 375143 INT1 32 hdr 15 24 45 02
ATVSEQ 3 2 INT1-4 t 401781 INT1 32 hdr 15 24 46 02
ATVSEQ 3 2 INT1-5 t 430843 INT1 32 hdr 15 24 47 02
ATVSEQ 3 2 INT1-6 t 459766 INT1 32 hdr 15 24 48 02
ATVSEQ 3 2 INT1-7 t 486695 INT1 32 hdr 15 24 49 02
ATVSEQ 3 2 INT1-8 t 514713 INT1 32 hdr 15 24 50 02
ATVSEQ 3 2 INT1-9 t 542967 INT1 32 hdr 15 24 51 02
ATVSEQ 3 2 INT1-10 t 571172 INT1 32 hdr 15 24 52 02
ATVSEQ 3 2 INT1-11 t 600709 INT1 32 hdr 15 24 53 02
ATVSEQ 3 2 INT1-12 t 628597 INT1 32 hdr 15 24 54 02
ATVSEQ 3 2 INT1-13 t 656512 INT1 32 hdr 15 24 55 02
ATVSEQ 3 2 INT1-14 t 684469 INT1 32 hdr 15 24 56 02
ATVSEQ 3 2 INT1-15 t 713757 INT1 32 hdr 15 24 57 02
ATVSEQ 3 2 INT1-16 t 741209 INT1 32 hdr 15 24 58 02
ATVSEQ 3 2 Pause t 9784 INT3 32
ATVSEQ 3 2 Pause-2 t 362684 INT2 12
ATVSEQ done

References