# set-def-tape-blk command

There are two methods to configure the drive in variable
block size mode:

- By executing commands.

- By placing the command in the dm, md, user-coldstart item.

For Windows: Not Supported

**For AIX:** Not Supported

For Linux: Supported

Note: To use this command, you must have root privileges
and the D3 port must be started by entering d3 -0 -l (lowercase `l`).

## Syntax

```
set-def-tape-blk block.size device.number
```

## Parameter(s)

| block.size | Size of the block. |
| --- | --- |
| device.number | Number of the tape device. |
From the TCL prompt:

- Enter: ```
list-device
``` Review the list of devices and determine the correct device.

- Enter: ```
!mt -f device.name setblk 0
``` where device.name is the device name listed in the TCL command. Execute this command after every Linux shutdown.

## Example(s)

To set tape device number 5 to
a physical block size of 512, enter:

```
set-def-tape-blk 512 5
```

---
Source: https://d3codex.com/tcl/set-def-tape-blk-command/ - part of the D3Codex reference.