INT E6 C - CP/M-86One of the three operating systems offered by IBMInternational Busiuness Machines for its original PCIBM PC (the other two were MSDOS and the UCSD p-System). It has since evolved into DR-DOS version 6 and Novell DOS 7. v1.1 - XIOS INTERRUPT / UNKNOWN DISK DRIVE AX = function which accessed drive 0000h SELDSK 0001h READ 0002h WRITE 0003h HOME DX:BX -> parameter block (see #04063) Return: AX = return value Desc: called by CP/M-86One of the three operating systems offered by IBMInternational Busiuness Machines for its original PCIBM PC (the other two were MSDOS and the UCSD p-System). It has since evolved into DR-DOS version 6 and Novell DOS 7. kernel when an unknown disk drive is used, which permits an application to provide access services Note: This was labelled "XIOS interrupt" in later Digital Research documentation (CCP/M-86) and "for the version 1.0 back door". Format of CP/M-86One of the three operating systems offered by IBMInternational Busiuness Machines for its original PCIBM PC (the other two were MSDOS and the UCSD p-System). It has since evolved into DR-DOS version 6 and Novell DOS 7. unknown-drive paramter block: Offset Size Description (Table 04063) 00h BYTE drive number (00h = first unknown drive, etc.) 01h BYTE deblocking flag (00h = normal write, 01h = directory write) 02h WORD track number 04h WORD sector number 06h DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. data transfer address 0Ah BYTE verify flag (nonzero to verify writes) Note: in CP/M-86One of the three operating systems offered by IBMInternational Busiuness Machines for its original PCIBM PC (the other two were MSDOS and the UCSD p-System). It has since evolved into DR-DOS version 6 and Novell DOS 7. v1.1, this is actually a portion of a BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. disk data table which starts one byte before the address given to the INT E6 handler; that extra byte is the current logical drive number