|
|
 |
 |
|
|
|
|
|
控制文件丢失的解决办法
|
|
|
|
编辑：华夏媒体 作者：未知 来源：网络 时间：2006-07-29 总浏览量：1552 |
|
文字大小：[ 大 中 小 ]
文字颜色： 双击滚屏/单击停止 |
|
[上一页] [1] [2] [3] [4] [5] [6] [7] [下一页]
|
-- not necessarily define the type of device used to write the file. Thus it
-- is necessary to specify the device type in order to interpret the file
-- handle. The NULL device type is defined for all systems. It is the file
-- system supplied by the operating system. The sequential file handles are
-- thus normal file names.
--
-- A device can be specified either by name or by type.
-- If the type is specified but not the name, the system picks an
-- available device of that type.
-- If the name is specified but not the type, the type is determined
-- from the device.
-- If neither the type or the name is given, the backups are files in
-- the operating system file system.
-- Note that some types of devices, optical disks for example, can be shared
-- by many processes, and thus do not really require allocation of the device
-- itself. However we do need to allocate the context for accessing the
-- device, and we do need to know the device type for proper interpretation
-- of the file handle. Thus it is always necessary to make the device
-- allocation call before making most other calls in this package.
--
-- Input parameters:
-- type
-- If specified, this gives the type of device to use for sequential
-- I/O. The allowed types are port specific. For example a port may
-- support the type "TAPE" which is implemented via the Oracle tape
-- API. If no type is specified, it may be implied by specifying a
-- particular device name to allocate. The type should be allowed to
-- default to NULL if operating system files are to be used.
|
|
[上一页] [1] [2] [3] [4] [5] [6] [7] [下一页]
|
|
|
打印 收藏 关闭 至顶部 |
|
 |
|