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Extended RAM Disk Driver

The Extended RAM disk driver uses RTTarget-32 Extended RAM Management API to allocate a disk image.

ERAM disks format themselves automatically as a FAT-16 or FAT-32 volume when the disk is mounted, unless it was formatted already. The application can reformat ERAM disks as exFAT, if desired. Up to 8 ERAM disks can be installed.

The ERAM Disk driver is reentrant. Device flag RTF_DEVICE_NEW_LOCK is supported for each ERAM disk.

RTFDevice.DeviceType

RTFDevice.DeviceType may be set to either RTF_DEVICE_FLOPPY or RTF_DEVICE_FDISK.

RTFDevice.DeviceNumber

This field is ignored and should be set to 0, even if several ERAM disks are used.

RTFDevice.DeviceFlags

Apart from device independent device flags documented in section Device List, the following flag can be specified for RTFDevice.DeviceFlags:

RTF_ERAM_CACHEABLE

When this flag is specified, the driver will apply flag RTT_ERAM_CACHEABLE in its call to RTT_ERAM_Alloc to enable the CPU RAM cache for the ERAM disk.

Please note that device independent flag RTF_DEVICE_SINGLE_FAT is not required, because the ERAM disk driver will format the ERAM disk with a file system with a single FAT by default. All other device independent flags documented in section Device List are supported.

RTFDevice.Driver

This field must point to RTFDrvERAM.

RTFDevice.DriverData

The ERAM disk driver requires a pointer to a structure of type RTFDrvERAMData for RTFDevice.DriverData with the following layout:

typedef struct { 
   DWORD Blocks; 
   ... 
} RTFDrvERAMData;

RTFDrvRAMData.Blocks specifies the number of 4 megabyte blocks of Extended RAM the ERAM disk will use. If set to 0, the driver will allocate all available Extended RAM for the ERAM disk.

The other fields of RTFDrvERAMData are for the driver's internal use and should be left uninitialized or initialized to 0.

Device Drivers

RAM Disk Driver

Linear Flash Driver