The DOS 3.3 sys.com bug hunt

The DOS 3.3 SYS.COM Bug Hunt! SYS.COM corrupted a NetDrive image. But why? Posted: 2025-02-22 Tags: DOS, NetDrive, ForgotToCheckReturnCode 2025-02-24: Somebody over at Hacker News pointed me at the source code, and it confirms the bug and also how things like ambiguous media descriptor bytes are handled. Hat tip to mmastrac and I'll post an update after I digest everything. In ye olden days to make a diskette bootable you had to format it using the /s option of the FORMAT command. That works fine for blank disks, but software vendors had a small problem - they would sell you a disk with their software on it but they couldn't include the DOS files needed to make it bootable because they were not selling you DOS. To get around this they would leave space available on the disk and have you use the SYS command, which copied the magic boot loader code onto from your DOS disk onto their disk. There were some restrictions on where the free space was located and how much was required, b ... Read full article.