Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
08851 Media Support Major Always Apr 10, 2024, 01:40 Apr 12, 2024, 13:33
Tester pnp2084 View Status Public Platform MAME (Official Binary)
Assigned To pnp2084 Resolution Fixed OS Windows 10/11 (64-bit)
Status [?] Resolved Driver
Version 0.264 Fixed in Version 0.265 Build 64-bit
Fixed in Git Commit e2b3371 Github Pull Request #
Summary 08851: trs80l2 trs80m3 trs80m4 coco: DMK Disk format detection rejects single-sided DMK files
Description MAME fails to identify single-sided DMK disk image files and rejects loading them.
Steps To Reproduce Try to load a DMK file e.g.
mame -w trs80m3 -flop1 TRSDOS13.dmk

Results in:
Fatal error: Device 5.25" double density floppy drive load failed: Unable to identify image file format
Additional Information At least one problem: dmk_dsk.cpp checks for byte 4 to be zero but that byte contains flags (e.g. single-sided)
The "i =4" below should be "i = 5"
for (int i = 4; i < 0x10; i++)
    if (header[i] != 0x00)
        return 0;
Introduced by wilbertpol in this commit:

There may be other problems but this is the most likely.
Github Commit
Regression Version
Affected Sets / Systems trs80l2 trs80m3 trs80m4 coco
Attached Files
zip file icon (39,118 bytes) Apr 10, 2024, 01:40 Uploaded by pnp2084
TRSDOS OS version 1.3 for TRS-80 Model III
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Senior Tester
Apr 10, 2024, 11:14
edited on: Apr 13, 2024, 05:29