IBM XT 5160 Technical Reference page 155

Interrupt Address
Function
20 80-83 DOS program terminate
21 84-87 DOS function call
22 88-8B DOS terminate address
23
8c-8F DOS Ctrl Break exit address
24 90-93 DOS fatal error vector
25 94-97
DOS absolute disk read
26 98-9B DOS absolute disk write
27 9C-9F
DOS terminate, fix in storage
28-3F AO-FF Reserved for DOS
40-5F 100-17F Reserved for BIOS
60-67 180-19F Reserved for user program interrupts
68-6F 1AO-1BF
Not used
80-85 200-217 Reserved for BASIC
86-FO
218-3C3 Used by BASIC interpreter wh i le
BASIC is running
F1-FF
3C4-3FF
Not used
Hardware, Basic, and DOS Interrupts
Address Mode
400-4A1 ROM BIOS
4A2-4EF
4FO-4FF
500-5FF
500
DOS
504
510-511
512-515
516-519
51A-51D
DOS
BASIC
BASIC
BASIC
BASIC
Function
See BIOS listing
Reserved
Reserved as intra-application
communication area for any application
Reserved for DOS and BASIC
Print screen status flag store
O=Print screen not active or successful
print screen operation
l=Print screen in progress
255=Error encountered during print
screen operation
Single drive mode status byte
BASIC's segment address store
Clock interrupt vector segment:offset store
Break key interrupt vector segment:offset
store
Disk error interrupt vector segment:offset
store
Reserved Memory Locations
5-8 System BIOS