What is Reset(handle,1)?

I came across this code of Reset(elfhandle,1) and I don't know what the second input 开发者_运维知识库of 1 does. What does the second input of Reset specify?

The second parameter in the System.Reset function is the record size to be read.

You can find more info in the Delphi online help.

RecSize is an optional expression that can be specified only if F is an untyped file. If F is an untyped file, RecSize specifies the record size to be used in data transfers. If RecSize is omitted, a default record size of 128 bytes is assumed.