burst mode

[Mingteh Michael Chen]

Dear Netters:
I am a novice in the group, so please bear with me if I am wrong. 8-)

My question is :

What is the burst mode of the Micro channel architecture?
and what makes it to be superior than other approaches? (maybe DMA?)
I have some vague idea that it transfers a whole memory "block"
instead of a memory word individually. But as long as the bus bandwidth is
fixed, each memory "word" still needs to be transferred sequentially...

Thank you very much for any comments or directions!

Regards,

--
Mingteh Chen
State Univ. of New York at Buffalo,
Dept. of Electrical & Computer Engineering
INTERNET: che...@acsu.buffalo.edu

[Robert Ellefson]

In article L...@acsu.buffalo.edu, che...@acsu.buffalo.edu (Mingteh Michael Chen) writes:

>What is the burst mode of the Micro channel architecture?
>and what makes it to be superior than other approaches? (maybe DMA?)
>I have some vague idea that it transfers a whole memory "block"
>instead of a memory word individually. But as long as the bus bandwidth is
>fixed, each memory "word" still needs to be transferred sequentially...
>

As I remember, the Streaming Data Mode (which I am assuming is
what you mean by 'burst mode') allows for block transfers to occur
without needing to setup the address for each word, so that the clocking
for each data word after the start of the block is much faster.
(Normally, you setup the address before you clock the data, because different
portions of the address space have different access times, which requires different
wait state assertions.) Also, there is now (with the RS/6000, at least)
a 64 bit streaming data mode, which uses both the address and data busses
for data transfer.

Other than the 64 bit transfer option, I'm not sure that the microchannel
approach is significantly better than others. (Nubus at least has a comparable
block transfer mode (not 64 bit)). Maybe someone more recently familiar with
the other existing bus protocols can give a better comparison, though.