The sysdevices table in the master database contains one row for each database device and may contain a row for each dump device (tape, disk, or operating system file) available to Adaptive Server.
The disk init command adds entries for database devices to master..sysdevices. Dump devices, added with the system procedure sp_addumpdevice, are discussed in Chapter 26, “Developing a Backup and Recovery Plan.”
sysdevices stores two names for each device:
A logical name or device name, used in all subsequent storage-management commands, is stored in the name column of sysdevices. This is usually a user-friendly name, perhaps indicating the planned use for the device, for example “logdev” or “userdbdev.”
The physical name is the actual operating system name of the device. You use this name only in the disk init command; after that, all Adaptive Server data storage commands use the logical name.
You place a database or transaction log on one or more devices by specifying the logical name of the device in the create database or alter database statement. The log on clause to create database places a database’s transaction log on a separate device to ensure full recoverability. The log device must also have an entry in sysdevices before you can use log on.
A database can reside on one or more devices, and a device can store one or more databases. See Chapter 21, “Creating and Managing User Databases,” for information about creating databases on specific database devices.
