Contents of the IOMON.DOC file
IOMON - Disk I/O monitor 13-May-86 S.H.Smith
Public domain material
'IOMON' is a small resident utility that monitors disk I/O activity.
It intercepts the disk I/O interrupt and displays I/O status information
on the screen during I/O wait periods.
The status information is displayed as a single character in the upper
right corner of the screen.
The following status codes are displayed:
I - Initialize function
R - Read data
W - Write data
V - Verify data
F - Format tracks
* - Other functions (usually special hard disk functions)
IOMON accesses video ram directly to reduce overhead. It will operate with
displays that are at either B000 or B800. For other displays, you will
get the message:
"ERR: CAN'T FIND VIDEO RAM"
IOMON won't work if you get this message.
IOMON does not interfere with disk I/O in any way. It should work properly
with any disk (or ram-disk) that is accessed through the disk services at
If a disk error is detected, IOMON will display the hex error code in flashing
reverse video. Here is a list of common error codes:
01 - Illegal function
02 - Address mark not found
03 - Write protect error
04 - Sector not found
08 - DMA overrun
09 - Attempt to DMA accross a 64k boundary
10 - Bad CRS on disk read
20 - Controller failure
40 - Seek failure
80 - Device timeout (device not ready)