Chapter 46. Configuring the DISK I/O Package
This chapter shows how to include the DISK I/O package an eCos configuration and how to configure it once installed.
46.1. Including DISK I/O in a Configuration
The DISK I/O subsystem is contained in a single eCos package, CYGPKG_IO_DISK. However, it depends on the services of the following other packages for complete functionality:
- Device IO package. Disk devices operate within the generic device infrastructure.
- The error package. Disk devices need to return standard error codes when operations fail.
The DISK I/O package can be added to any configuration just by adding its package during configuration. However, it is usually added as part of a group which also includes a filesystem implementation and hardware device drivers.
46.2. Configuring the DISK I/O Package
The option "Detect FAT boot sector"
CYGSEM_IO_DISK_DETECT_FAT_BOOT) can be used with certain
types of removable media which are treated undeterministically by
Windows PCs, such as USB keys. These usually contain a partition table,
but if completely wiped, Windows will not recreate the partition table,
and instead place a FAT filesystem directly on the device with no
partition table. Enabling this option detects this and fabricates a
partition table in memory instead. This option is usually only needed on
systems which use removable media likely to be shared with Windows PCs,
as indicated from low level drivers with the
CYGINT_IO_DISK_DETECT_FAT_BOOT_DEFAULT CDL interface.
The CDL option
used to support media formatted with an Extensible Firmware
Interface (EFI) GUID Partition Table (GPT). This is limited to
media presenting a single \"protective\" MBR partition entry
covering the GPT managed space. Currently the feature is
limited to providing the number of partitions supported by the
parent filesystem package, and only those partitions
accessible using 32-bit LBA values.
The CDL interface
indicates to the disk I/O package, and to its users, that data transfer
buffers need to be aligned to data cache line boundaries.
The CDL interface
that the hardware disk driver implements removable media support. This
will cause the disk I/O package to implement the
CYG_IO_GET_CONFIG_DISK_EVENT configuration option
|2023-08-15||eCosPro Non-Commercial Public License|