Hi Rick,
=20
I am still not too sure about the size of the buffer needed. Is it true =
that if  the receiver's speed is 1byte/sec and transmitter speed's is =
4byte/sec then buffer size of 4-byte is needed.
=20
Thank you and have a nice day.
=20
Regards,
Lee

________________________________

From: pic microcontroller discussion list on behalf of Rick C.
Sent: Mon 1/12/2004 11:03 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [OT:] What is a buffer



A buffer is a temporary storage area. It is usually used to store =
incoming or outgoing data where there are differences in speed in
the sending and receiving application or device. The size of the buffer =
depends upon the ratio of the two applications speed. You
always want to have enough buffer memory. Obviously, if an app sends too =
fast, a overrun error and loss of data will occur. More
memory would then be needed or buffer space allocated. Some applications =
use handshaking to temporarily halt the flow of data until
the receive app processes it. Buffers are used in almost all =
applications related to computers. You have keyboard buffers, hard
drive buffers, memory buffers, modem buffers, i/o buffers (comm ports), =
CD burners, etc.

CD burners can have an underrun error. This is because the data being =
burned has to burn at a certain rate. If the computer doesn't
have the data ready in time, the burner will not keep up and damage the =
CD will occur. Most later software calculates and caches the
data into a buffer so there will always be data ready until the CD burn =
is completed.

Rick

#LEE CHUN YONG# wrote:

> Hi All,
>
> I notice nowadays a lot of devices are having buffer of certain size. =
What is a buffer actually and what are the purposes of it?

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