The Ftape Installation and Usage Guide - zftape devices
To support some new features, I added new flag bits to the minor device number. These are (see [/usr/src/ftape-4.03/]include/linux/zftape.h) (1):
#define ZFTAPE_Q80_MODE 8 (= bit 3) #define ZFTAPE_RAW_MODE 32 (= bit 5)
Already present in Bas Laarhoven's original ftape was bit 2, indicating the non-rewind mode (see Rewinding and non-rewinding devices) of the driver, and the meaning of the first two bits that indicate the drive selection mode.See Drive selection.
There used to be another bit, namely
#define ZFTAPE_ZIP_MODE 16 (= bit 4)
This bit of the minor device number used to switch-on ftape-3.04d's
user-transparent compression feature (or bug). ftape-4.03 still
understands this bit, but doesn't support writing of compressed archives
any more; however, decompression of compressed archives
produced by ftape-3.04d is still supported. Consequently, the
ftape-4.03 treats the tape cartridge as write protected when used with
a device node with this bit set (i.e. `/dev/zqft0
',
`/dev/nzqft0
' etc.).
The actual minor-device number is simply computed by a bitwise `or
'
of the bits that correspond to the desired features. A non rewinding
device for example has the following minor device number (drive
selection method A):
FTAPE_NO_REWIND | ZFTAPE_SELECT_A = 4 | 0 = 0x04 = 4
Consequently, there are 16 different ftape devices.
And, if you also count the obsolete devices `/dev/[n]zqft0
', ...,
`/dev/[n]zqft0
', eight additional device-nodes which are only kept
in order not to break compatibility with older versions of the
ftape driver.
(1) The meaning of the ZFTAPE_Q80_MODE bit has changed from version 1.02 to version 1.03. To be more precise, this bit is meaningless now, it is just kept for compatibility reasons.
![]() |
Use these buttons to jump to the top menu |