I$Attach
From NitrOS-9
| Attach Device | Attaches a device to the system or verifies device attachment. |
| OS9 I$Attach 103F 80 |
Entry Conditions
A access mode
X address of the device name string
Exit Conditions
X updated past device name
U address of the device table entry
Error Output
CC carry set on error
B error code, if any
Additional Information
- Attach does not reserve the device. It only prepares the device for later use by any process.
- NitrOS-9 installs most devices automatically on startup. Therefore, you need to use Attach only when installing a device dynamically or when verifying the existence of a device. You need not use the Attach system call to perform routing I/O.
- The access mode parameter specifies the read and/or write operations to be allowed. These are:
0 = Use any special device capabilities
1 = Read only
2 = Write only
3 = Update (read and write)
- Attach operates in this sequence:
- NitrOS-9 searches the system module to see if any memory contains a device descriptor that has the same name as the device.
- NitrOS-9’s next operation depends on whether or not the device is already attached. If NitrOS-9 finds the descriptor and if the device is not already attached, NitrOS-9 link the device’s file manager and device driver. It then places the address of the manager and the driver in a new device table entry. NitrOS-9 then allocates any memory needed by the device driver, and calls the driver’s initialization routine, which initializes the hardware.
- If NitrOS-9 finds the descriptor, and if the device is already attached, NitrOS-9 verifies the attachment.
