RE: Wanted: a faster protocol for IEEE devices

From: Baltissen, GJPAA (Ruud) <>
Date: Wed, 18 Sep 2013 07:41:26 +0000
Message-ID: <>
Hallo allemaal,

> One idea I had was looking for the very first sector I would run into
> and then copying every byte that passed under the head and that X
> bytes long. 

I just realized that this won't work :( The above idea is not mine, this is the way Star Commander works. But to be able to read the byte and to send it the next moment, all should be done by one single CPU. But, with the exception of the 2031, the IEEE drives have two CPUs: one handling the disk, the other handling the IEEE bus. How does the disk CPU tell the bus CPU that one byte has been read without loosing too much time?
An idea would be reading one whole track, but then we would need at least 8 KB of RAM just for buffering the data. And as I wrote to Gordon, we only have 4 KB on board.
An in between solution: telling the bus CPU during the gap between two sectors that a sector has been read. While the disk CPU is filling another part of RAM with data, the bus CPU can send the data of the first sector. 

Met vriendelijke groet / with kind regards,
Ruud Baltissen

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