Product manual

Introduction to the Industrial Grade SD Card

1.5.1. Flash Technology Independence

The 512-byte sector size of the Industrial Grade SD Card is the same as that in an IDE magnetic disk drive. To write

or read a sector (or multiple sectors), the host computer software simply issues a Read or Write command to the

card. This command contains the address. The host software then waits for the command to complete. The host

software does not get involved in the details of how the flash memory is erased, programmed or read. This is

extremely important as flash devices are expected to get more and more complex in the future. Because the

Industrial Grade SD Card uses an intelligent on-board controller, the host system software will not require change

as new flash memory evolves. In other words, systems that support the Industrial Grade SD Card today will be able

to access future SanDisk SD Cards built with new flash technology without having to update or change host

software.

1.5.2. Defect and Error Management

Industrial Grade SD Cards contain a sophisticated defect and error management system. This system is analogous to

the systems found in magnetic disk drives and in many cases offers enhancements. For instance, disk drives do not

typically perform a read after write to confirm the data is written correctly because of the performance penalty that

would be incurred. Industrial Grade SD Cards do a read after write under margin conditions to verify that the data is

written correctly. In the rare case that a bit is found to be defective, SD cards will replace the bad bit with a spare bit

within the sector header. If necessary, SD cards will even replace the entire sector with a spare sector. This is

completely transparent to the host and does not consume any user data space.

The Industrial Grade SD Card soft-error-rate specification is much better than the magnetic disk drive specification.

In the extremely rare case a read error does occur, SD cards have innovative algorithms to recover the data. This is

similar to using retries on a disk drive but is much more sophisticated. The last line of defense is to employ a

powerful ECC to correct the data. If ECC is used to recover data, defective bits are replaced with spare bits to

ensure they do not cause any future problems. These defect and error management systems coupled with the solid-

state construction give SD cards unparalleled reliability.

1.5.3. Copyright Protection

A detailed description of the Copyright Protection mechanism and related security SD Card commands can be found

in the SD Card Security Specification document from the SD Card Association. All Industrial Grade SD Card

security related commands operate in the data transfer mode.

As defined in the SDMI specification, the data content that is saved in the card is saved already encrypted and it

passes transparently to and from the card. No operation is done on the data and there is no restriction to read the

data at any time. Associated with every data packet (song, for example) that is saved in the unprotected memory

there is a special data that is saved in a protected memory area. For any access (any Read, Write or Erase command)

from/to the data in the protected area. For an authentication procedure is done between the card and the connected

device, either the LCM (PC for example) or the PD (portable device, such as SD player). After the authentication

process passes, the card is ready to accept or give data from/to the connected device. While the card is in the

secured mode of operation (after the authentication succeeded) the argument and the associated data that is sent to

the card or read from the card are encrypted. At the end of the Read, Write or Erase operation, the card gets out

automatically of its secured mode.