Tandy 1000 Programmer's Reference Manual page 20

ChaDter 1 I System Calls
The following are error codes for Interrupt 24H:
Error Code Description
0
1 Unknown unit
2
Drive not ready
3 Unknown command
4
Data Error
5 Bad request structure length
6 Seek error
7 Unknown media type
8 Sector not found
9 Printer out of paper
A Write fault
B
Read fault
C General failure
Attempt to write on write-protected disk
The user stack will be in effect and, from top to bottom,
will contain the following:
IP
MS-DOS registers from
cs
issuing INT 24H
FLAGS
AX
BX
INT 21H request
cx
DX
SI
DI
BP
DS
ES
IP
From the original INT 21H
cs
from the user to MS-DOS
FLAGS
User registers at time of original
If a n IRET is executed, the registers are set to cause
MS-DOS to respond according t o the contents of AL as
follows:
AL
= 0
ignore the error
= 1 retry the operation
= 2
terminate the program via 23H
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