Data type


Default value


64–4,096 ( bytes )



Specifies the size of the character buffers for a named pipe . The redirector maintains a read-ahead buffer and a write-behind buffer for each pipe. This entry establishes the size of both buffers.

The buffer size determines the amount of data the redirector reads and writes.

When reading, the redirector attempts to read enough data to fill the read buffer. If the data it is reading is smaller than the buffer, the redirector reads ahead until the buffer is full. If the data is larger than the buffer, the redirector bypasses the character-mode buffer and reads the data directly into the user buffer.

When writing, the redirector collects data in the character-mode buffer until it meets or exceeds the size specified by the value of the MaxCollectionCount entry, or until the time specified by the value of the CollectionTime entry expires.

Increasing the value of this entry can improve the performance of named-pipe applications, but it does not affect applications, such as SQL Server applications, that do their own buffering.

Note Image Note

Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits it.