Int 13h, 06h            Format Track and Set Bad Sector Flags      fixed disk

Initializes each sector on a specified cylinder with sector
address and size information; also marks the sectors on the track
as unusable (bad) by setting the bad sector flag in the ID fields.
Only XTs may use this service.

Entry AH = 06h
AL = Interleave value
CH = Cylinder number (10-bit value; upper 2 bits in CL)
DH = Head number
DL = Drive number (Bit 7 must be set)

Return AH = Status of operation (See Service 01h)
CF Set if error, cleared otherwise

──────────────────────────────────────────────────────────────────

Note
This service will destroy all previous contents of the disk.

The cylinder number is a ten-bit quantity (0 through 1023). Its
most significant two bits are in bits 7 and 6 of CL; the remaining
eight bits are in CH.

If an error is encountered, use Service 0h to reset the drive and
retry the operation.