# System Parameters

'SB' | Self-Block Extracts

## Description

(UNIX/Linux Only)

By default, UNIX/Linux locks records by file and process, not by channel number. This can cause unexpected results if you lock a record on one channel and access it on another.

This issue can be avoided by setting the 'SB' (Self Block) parameter, which will check to see if the record is locked (EXTRACTED) on another channel.

Like Windows, the 'XI' system parameter will govern whether you can read a locked record, regardless of the setting of the 'SB' parameter.

## Default

On - as of PxPlus 2021

(Prior to PxPlus 2021, the default setting was Off.)

## See Also

'XI' Extract Ignore'