TD_RAWREAD/ETD_RAWREAD - read raw data from the disk.

These commands read a track of raw data from disk and deposits it in the provided buffer. The data is taken straight from the disk with no processing done on it. It will appear exactly as the bits come out off the disk, hopefully in some legal MFM format.

This command is directly forwarded to the trackdisk.device.

io_Device

preset by the call to OpenDevice()

io_Unit

preset by the call to OpenDevice()

io_Command

TD_RAWREAD or ETD_RAWREAD.

io_Flags

if the IOTDB_INDEXSYNC bit is set then the driver will make a best effort attempt to start reading from the index mark. Note that there will be at least some delay, and perhaps a great deal of delay (for example if interrupts have been disabled).

io_Length

Length of buffer in bytes, with a maximum of 32768 bytes.

io_Data

Pointer to CHIP memory buffer where raw track data is to be deposited.

io_Offset

The number of the track to read in.

iotd_Count

(ETD_RAWREAD only) maximum allowable change counter value.

io_Error

0 for success, or an error code as defined in <devices/trackdisk.h>

The track buffer provided MUST be in CHIP memory

TD_RAWWRITE, trackdisk autodocs