RE: Wanted: a faster protocol for IEEE devices

From: Baltissen, GJPAA (Ruud) <ruud.baltissen_at_apg.nl>
Date: Wed, 18 Sep 2013 07:41:26 +0000
Message-ID: <54F350D2C6501448A3EE14B7854C5FB50DAEBFBF@WSV10441N3.office01.internalcorp.net>
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




De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de 
geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te 
nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit 
e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. 
Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige 
overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij 
overgebrachte virussen.

APG Algemene Pensioen Groep NV is gevestigd te Heerlen en is ingeschreven in het 
handelsregister van de Kamer van Koophandel Limburg onder nummer 14099617


The information contained in this e-mail is confidential and may be privileged. 
It may be read, copied and used only by the intended recipient. 
If you have received it in error, please contact the sender immediately by 
return e-mail; please delete in this case the e-mail and do not disclose its 
contents to any person. We don't accept liability for any errors, omissions, 
delays of receipt or viruses in the contents of this message which arise as a 
result of e-mail transmission.

APG Algemene Pensioen Groep NV is registered in the trade register of the Chamber 
of Commerce Limburg, The Netherlands, registration number: 14099617


       Message was sent through the cbm-hackers mailing list
Received on 2013-09-18 08:00:03

Archive generated by hypermail 2.2.0.