INT 15 - MultiDOS Plus - GET SYSTEM BLOCK
AH = 15h
Return: BX:AX -> system block (see below)

Format of MultiDOS Plus 4.0 system block:
Offset  Size    Description
00h    WORD    segment of system control block
02h    WORD    redirection flag set by /NOREDIRECT
04h    WORD    no-INT 10 flag set by /NO10
06h    DWORD   old INT 10
0Ah    DWORD   new INT 10
0Eh    DWORD   pointer to WORD with current TCB offset (see AH=13h)
12h    DWORD   pointer to WORD with idle task TCB offset
16h    DWORD   pointer to WORD with foreground TCB offset
1Ah    DWORD   pointer to WORD with MultiDOS TCB offset
1Eh    WORD    Task Control Block size
20h    WORD    number of TCBs
22h    WORD    flag: EMS present
24h    WORD    EMS page frame base segment
26h    WORD    16K pages in EMS page frame
28h    WORD    base segment for conventional memory tasks
2Ah    WORD    conventional memory size in paragraphs
2Ch    DWORD   pointer to list of queue pointers

See also: 1513

1515 - MultiDOS Plus - GET SYSTEM BLOCK