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devb-ram

Driver for RAM disk interface (QNX Neutrino)


Note: You must be root to start this driver.

Syntax:

devb-ram [cam option[,option]...]
         [disk option[,option]...] 
         [ram option[,option]...]
         [blk option[,option]...] &

Options:


Note: Use commas (,) to separate the options. You can put the cam, disk, ram, and blk groups of options in any order.

cam options

quiet
Be quiet: don't display any information on startup.
verbose
Be verbose.

disk options

The disk options control the driver's interface to cam-disk.so. If specified, they must follow the disk keyword. For more information, see cam-disk.so.

ram options

The ram options control the driver's interface to RAM.

capacity=blocks
Specify the capacity of the RAM drive in 512 byte blocks. The default is 4096 blocks (2Mbytes).

blk options

The blk options control io-blk.so. These options must follow the blk keyword and must be specified after any general or disk options. For more information, see io-blk.so.

Description:

The devb-ram driver creates a RAM disk interface. When the capacity option isn't specified, devb-ram creates a 2Mbyte RAM disk.

Examples:

Create a 4Mbyte RAM drive:

devb-ram ram capacity=8192 &

Files:

The devb-ram driver causes io-blk.so to adopt various block special devices under /dev. These devices are normally named hdn, where n is the physical unit number of the device.

This driver could also require the following shared objects:

Binary Required
cam-disk.so For RAM disk access.
libcam.so Always

Exit status:

The devb-ram driver terminates only if an error occurs during startup, or if it has successfully forked itself upon startup because it hadn't been initially started in the background.

0
The devb-ram driver wasn't started in the background and therefore forked itself. The original process terminated with a zero exit status, the forked process continued.
> 0
An error occurred during startup.

Caveats:

While there's no limit to the size of a disk or partition, I/O (i.e. the lseek(), read() and write() functions) is currently limited to 2 gigabytes per partition (or disk). This I/O limit has no effect on the partition size for mounted filesystems.

Known supported functions include:

chmod(), chown(), close(), closedir(), creat(), devctl(), dup(), dup2(), fcntl(), fpathconf(), fstat(), lseek(), mkdir(), mkfifo(), mknod(), open(), opendir(), pathconf(), read(), readdir(), readlink(), rewinddir(), rmdir(), stat(), symlink(), unlink() (not supported for directories), utime(), write()

Note that certain calls (such as pipe(), as well as read() and write() on FIFOs) may require the pipe manager.

See also:

cam-disk.so, devb-aha2, devb-aha4, devb-aha7, devb-aha8, devb-amd, devb-btmm, devb-ncr8, fs-dos.so, fs-qnx4.so, io-blk.so

"Block-oriented drivers (devb-*)," "Common access method (cam-*)," and "Filesystem drivers (fs-*)" in the Utilities Summary


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