TD_RAWREAD/ETD_RAWREAD - read raw data from the card.

Raw read data bytes - typical use is to read bytes from CIS for verification during writes. Bytes read from attribute memory can be done as multi-byte reads returning junk for odd byte addresses, though single byte reads from even byte addresses is recommended.

The caller MUST own the the card, and must pass in a valid pointer to the credit-card common memory, or attribute memory. the raw read function fails if the device owns the card.

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

Ignored.

io_Length

Length of buffer in bytes, with a maximum of 65535 bytes.

io_Data

Pointer to buffer where data is to be deposited.

io_Offset

Address in the credit card or attribute memory.

io_Error

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

Note that the use of the carddisk.device RAWREAD function makes it possible to use other deices if needed in the future which support RAWREAD commands like thse to read a new CIS from flash ROMs, SRAM cards with EEPROMs from attribute memory. Some vendors have attribute memory options for their SRAM cards. Of interest, these can actually be formatted as disks even if there is no writeable attribute memory. There is code for these cases:

1. A formatted card which lacks a device tuple as the first tuple in attribute memory. This works if there is a LINKTARGET tuple starting at mem location 0 in common memory, and the CISTPL_FORMAT tuple is stored in common memory.
   
   
2. Like #1, but there is a CISTPL_DEVICE tuple in common memory. This is technically not allowed, though supported by the device in anticipation of using SRAM cards which lack attribute memory.
   
   
3. The attribute memory, and common memory overlap, and the CIS has been properly written such that the CIS is stored in even bytes only until a LONGLINK_C tuple is found which continues the chain in contiguous bytes in common memory. POQET SRAM cards have such overlapped memory, as do Intel Flash-ROMS.
   
   

TD_RAWWRITE