a1200   NEWS   APPS   DOCS   ABOUT
a1200
----
a1200
----
Autodocs
 Devices:
 trackdisk.device
  CMD_CLEAR
  CMD_READ
  CMD_UPDATE
  CMD_WRITE
  TD_ADDCHANGEINT
  TD_CHANGENUM
  TD_CHANGESTATE
  TD_EJECT
  TD_FORMAT
  TD_GETDRIVETYPE
  TD_GETGEOMETRY
  TD_GETNUMTRACKS
  TD_MOTOR
  TD_PROTSTATUS
  TD_RAWREAD
  TD_RAWWRITE
  TD_REMCHANGEINT
  TD_SEEK
Include
GuruMeditation
Docs » Autodocs » trackdisk.device » CMD_READ

NAME

	CMD_READ/ETD_READ -- read sectors of data from a disk.

FUNCTION

	These commands transfer data from the track buffer to a supplied
buffer. If the desired sector is already in the track buffer, no disk
activity is initiated. If the desired sector is not in the buffer, the
track containing that sector is automatically read in. If the data in
the current track buffer has been modified, it is written out to the
disk before a new track is read. ETD_READ will read the sector label
area if the iotd_SecLabel is non-NULL.
IO REQUEST INPUT
io_Device preset by the call to OpenDevice()
io_Unit preset by the call to OpenDevice()
io_Command CMD_READ or ETD_READ
io_Flags 0 or IOF_QUICK
io_Data pointer to the buffer where the data should be put
io_Length number of bytes to read, must be a multiple of
TD_SECTOR.
io_Offset byte offset from the start of the disk describing
where to read data from, must be a multiple of
TD_SECTOR.
iotd_Count (ETD_READ only) maximum allowable change counter
value.
iotd_SecLabel (ETD_READ only) NULL or sector label buffer pointer.
If provided, the buffer must be a multiple of
TD_LABELSIZE.
IO REQUEST RESULT
io_Error - 0 for success, or an error code as defined in
<devices/trackdisk.h>

NOTES

	Under versions of Kickstart earlier than V36, the io_Data had to
point to a buffer in chip memory. This restriction is no longer
present as of Kickstart V36 and beyond.

SEE ALSO

CMD_WRITE()

Comments

Name:
E-mail: Use this if you want a message if you get a response, will not be shown.
Comment:
Select correct short for:

The Black Lotus

TBL
HZ
AYS
CSL

Comments:

$VER: d0.se 1.14 Copyright © 2011-2021 Tobias Geijersson support at d0 dot se