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Diffstat (limited to 'results/scraper/launchpad-without-comments/1854878')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1854878 | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1854878 b/results/scraper/launchpad-without-comments/1854878 new file mode 100644 index 00000000..e62e79b5 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1854878 @@ -0,0 +1,32 @@ +Physical USB thumbdrive treated as read-only + +So I have installed FreeDOS on my USB thumbdrive, by using Rufus. Everything goes as expected so far. That's good. + +When I run QEMU with this command line: +qemu-system-x86_64.exe -drive file=\\.\PhysicalDrive1 + +it of course is read-only, just like the resulting console message says: +WARNING: Image format was not specified for '\\.\PhysicalDrive1' and probing guessed raw. + Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted. + Specify the 'raw' format explicitly to remove the restrictions. + + +So what I then did, was I ran QEMU with this command line: +qemu-system-x86_64.exe -drive file=\\.\PhysicalDrive1,format=raw + +As expected, the above mentioned console message no longer appears. +However, beyond that, QEMU doesn't behave as it should regarding read-only status. When I try any operation that involves writing to the drive, it becomes quite clear that the drive is still read-only. Any writing operations to the drive result in FreeDOS giving me the error message: +Error writing to drive C: DOS area: sector not found. + +The above situation is clearly a bug. QEMU should not be treating it as read-only once I specify format=raw. + +Note that drive C is how the guest OS refers to the USB thumbdrive (it's drive E in my host OS, and drive C in my host OS is the actual system drive). + +And yes, it is a QEMU bug. It's not a FreeDOS bug I tested it with this command line, so that all changes would be written to a temporary snapshot file: +qemu-system-x86_64.exe -drive file=\\.\PhysicalDrive1,format=raw,snapshot +That last drive option "snapshot" tells QEMU to create a temporary snapshot file, and to write all changes to that. When I do that, all write operations are successful. So it seems that there is a bug in QEMU where it keeps read-only mode in place for a physical drive, even when format=raw is specified. Please fix this bug. Thanks in advance. + +Here's my current setup. +Host OS: Windows 10 (64bit) +Guest OS: FreeDOS +QEMU version: 4.1.0 \ No newline at end of file |